Aung Htay Oo
Department of Fisheries, Ministry of Livestock and Fisheries
E-mail: aunghtayoo21@gmail.com
Myanmar has an extensive system of inland water resources, the great bulk of which are still in a pristine
condition. Fish, consumed in fresh and many processed forms is an important component of the protein
intake of the population; consumption is estimated at 43 kg capita
 in 2008-2009. Stock enhancement
of inland waters in Myanmar has been conducted since 1967, initiated through a seed replenishing program
to the natural water, such rivers, lake, dams even rice fields etc. The National Fisheries Development Plan and
National Resource Management Policy aim to increase fish production by stocking fish and prawn seeds
into dams, reservoirs, and other natural waters bodies and combined with improved public awareness on
conservation of fisheries resources towards sustainable fisheries development.
Key words: Inland fisheries; replenishing and conservation.
Myanmar is divided into seven major topographical regions: the Northern Hills, the Western Hills, the Shan Plateau,
and the Central Belt, the lower Myanmar Delta, the Rakhine Coastal Region and the Tanintharyi Coastal Strip.
Overall Myanmar posses a wide range of inland water resources, the major resources being associated with the
two river systems, Ayeyarwaddy (2 170 km long), Chindwin (960 km) and Sittaung, and their vast flood plains and
deltaic areas. In addition, there are three large natural lakes Lake Inle (in Shan Plateau), Indawgyi (in Kachin State)
and Indaw (in Katha) with approximately water area of 15 500 ha, 12 000 ha and 2 850 ha, respectively.
Fish is a very important component of the diet of the people of Myanmar, with an estimated per caput
consumption of 43 kg per year in 2008-2009, which is one of the highest in the region. Fish is consumed fresh
and in various processed forms, fermented fish being a staple part of the daily diet of most people. All inland
waters, except reservoirs, are utilized for inland fish production. However, most remains artisanal. Stock
enhancement practices of varying forms were employed since 1967 to increase inland fish production, which
currently stands around 899 430 tonnes.
The inland waters of Myanmar also possess a high biological diversity, particularly of finfish. For example the fish
fauna of inland natural lakes exhibits a high degree of endemicity, and actions have been launched under the
National Fisheries Development Plan and National Resource Management Policy to conserve the biodiversity of
inland waters.
This review attempts to address the stock enhancement practices in inland waters of Myanmar and the actions
taken to conserve biodiversity in the inland waters.
In 2008-2009, the total fish production in Myanmar was around 3 542 290 tonnes of which 899 430 tonnes is from
inland fish and accounting for approximately 26 percent of the total (Table 1). Over the years, the contribution
of inland fish production to the total, as in the case of aquaculture, has gradually increased (Figure 1) and
consequently become an important means of food fish supply to the population. These increases in fish
production have been achieved through the introduction of several measures, one of which is stock enhancement
and other measures relevant to biodiversity conservation.94
Table 1.  Trends in fisheries production (in x 1000 tonnes) from 1989-1999 to 2008-2010 in Myanmar.
Note that leasable and open fisheries are the main forms of inland fisheries
Year Total Culture Leasable Open Marine
1989-1999 1 011.18 91.17 67.87 91.98 760.16
1999-2000 1 195.80 102.60 83.06 113.00 897.14
2000-2001 1 309.83 121.95 91.17 147.04 949.67
2001-2002 1 474.46 190.12 95.95 158.93 1 029.46
2002-2003 1 595.87 252.01 109.53 180.61 1 053.72
2003-2004 1 986.96 400.36 122.28 331.98 1 132.34
2004-2005 2 217.47 485.22 136.79 366.75 1 228.71
2005-2006 2 581.78 574.99 152.69 478.43 1 375.67
2006-2007 2 859.86 616.35 170.10 548.09 1 525.32
2007-2008 3 193.92 687.67 191.05 625.44 1 689.76
2008-2009 3 542.19 775.25 209.72 689.71 1 867.51
Figure 1.  inland fisheries production in 10 years
The main forms of inland fisheries in Myanmar are open water fisheries and leasable fisheries. Inland fisheries are
all regulated by provisions in the Freshwater Fisheries Law (1991).
Freshwater Fishery Production
2.1 Leasable fisheries
There are currently 3 717 leasable fisheries in Myanmar of which 3 453 are still exploitable and the licenses are
issued by DOF (Department of Fisheries), Myanmar in 2008-2009. Leasable fisheries are key fishing grounds on
floodplains which are cordoned off by barrage fences and fished using various methods. The peak fishing season
involves capturing fishes migrating out of the floodplain as the water level recedes. This is referred to locally as
the “Inn” fishery in Myanmar language. The leases are auctioned yearly, but DOF has extended the lease period
up to nine years to promote improved long-term management (3 years x 3 times leases). The management
systems of leasable fisheries are normally handled by the DOF, mainly through the auctions which are conducted
in conjunction with townships and regional authorities.
 In this leasable fisher y, the lessee has the obligation and the right to exploit all the fish resources, using any form
of gear. The lessee is obliged to adopt stock enhancement practices, often provided by the DOF. The peak fishing95
season is August to October, when the flood waters recede. The production from leasable fisheries have increased,
albeit gradually, through the years and currently the production is around 200 000 tonnes (Table 1 and Figure 1).
Leasable fisheries could vary in intensity, from the management and production view point, some being treated
in a manner similar to large fish ponds or small reservoirs, and taking the form of culture-based fisheries. For
example, the leasable fishery of KanDawGyi (300 ha; permanent water body in Mandalay Division) has adopted
an exclusive stocking (2-3 million fingerlings of major carps per year) and recapture 500 to 600 thousand full
grown fish every year, averaging approximately 4 200 kg ha
 (FAO-NACA, 2003). In contrast, the leasable
fishery of Thaung-Tha-Man (600 ha; in Mandalay township), 60 percent of the yield is of the exotic Oreochromis
niloticus and the rest being of stocked species such as rohu, mrigal etc., with an overall average yield of
2 800 kg ha
 (FAO-NACA, 2003).
2.2 Open water fisheries
Open water fisheries in Myanmar refer to all forms of inland fisheries, except the leasable ones and reservoirs.
Almost all open water fisheries in inland waters are artisanal, and fishing is often conducted using non-motorized,
traditional wooden crafts. The permit or right to fish license is issued by DOF, Myanmar. All fishing gears require
a respective implementation license. For most licensees there is a set fee. Some of the larger gear such as
“stow net” set in rivers is allocated by tender system. Fees are variable between locations according to the
production levels and capacities. License fees for small gears are low. All gear licensees are expected to report
the daily catches to DOF. In some of the lakes, such as in Inle Lake, the gears that are used are unique to that
body of water; for instance the use of a conical bamboo devise surrounded by a moveable and maneuverable
small meshed net is typically used to catch fish by driving it to the bottom and lifting it gradually whilst closing
the net.
2.3 Social dimensions of inland fisheries in Myanmar
The great bulk of open water fisheries in Myanmar are artisanal and subjected to a licensing system for use of
any form of gear. However, there is an increasing tendency to auction the fishing rights of selected areas of lakes
and such open waters, in a manner comparable to that of lease fisheries of flood plain areas. In general, the
leasable fisheries, though in existence for over five decades, tend to marginalize the use of the water bodies by
the community, as often the more productive areas being leased are held on an almost continuous basis by the
richer more powerful segments of the society. This situation will be further exacerbated by the new plans to
increase the lease period up to nine years.
On the other hand, a long term lease will induce the lessees to improve the production of the water bodies,
adhere to more productive measures of stock enhancement, encourage more people be engaged in day to day
management, harvesting, marketing and other activities.
The biodiversity aspects of inland waters in Myanmar is best documented with respect of its three large natural
lakes, Inle, Indawgyi and Indaw, perhaps the best documentation among these being that of Lake Inle. Early
studies (Annandale, 1917) reported 23 to 42 species are found in Lake Inle and its inflows and outflows, which
included two endemic cyprinid genera,  Inlecypris and  Sawbwa. More recent data indicated that there are
36 species (Kullander, 1994), of which 16 are endemic to the Lake (Table 2), as well as seven species have been
introduced into it.
The most extensive survey of the fishes to date in Lake Indawgyi is by Prashad and Mukerji (1929) in which
43 finfish species were recorded. They considered that three of these,  Barbus sewelli (redescribed as  Puntius
orphoides), Burbas myitkyinae (redescribed as Hypsibarbus myitkyinae and Indostomus paradoxus were endemic
to the lake. However, all three of these species have also been found in other localities. A total of 67 species were
recorded in the Indawgyi Lake basin when inflowing streams and marshy areas were included. The endemic96
species found in lake (after further surveys and taxonomy changes) was the catfish Aky prashadi. However, there
are several endemics that Prashad and Mukerjin recorded from pools and streams in the Indawgyi lake basin:
Gudusia variegata (Clupeidae) which is mainly found in rivers in Myanmar,  Esomus altus (Cyprinidae) and
Salmostoma sladoni (Cyprinidae).
Table 2.  Fish species list of Lake Inle
Non-endemics Endemics Introduced or status uncertain
Notopterus notoptopterus Cyprinus carpio intha Colisa labiosa
Clarias batrachus Neolissochilus nigrovittatus Parambassis sp.
Monopterus cuchia Cirrhinus lu Parambassis lala
Monopterus albus Physoschistura brunneana Labeo rohita
Channa striata Physoschistura shanensis Ctenopharyngodon idellus
Ophicephalus butleri Yunnanilus brevis Glossogobius sp.
Chaudhuria caudata Sawbwa resplendens Trichogaster pectoralis
Lepidocephalichthys berdmorei Microrasbora rubescens Clarias garipinus
Acanthocobitis botia Microrasbora erythromicron
Physoschistura rivulicola Barilius auropurpureus
Puntius stoliczcanus Danio erythromicron
Amphipnous cuchia Inlecypris auropurpurea
Lepidocephalus berdmorei Poropuntius schanicus
Poropuntius sp.
Percocypris compressiformis
Gerra gravely
Silurus burmanensis
Channa harcourtbutleri
Macrognathus caudiocellatus
Mastacembelus oatesii
Mastacembelus caudiocellatus
Nemachilus brevis
Nemachilus brunncanus
Discognasthus lamta
Cirrhina latia
Barbus sarana caudimarginatus
Barbus scnanicus
Barbus stedmanensis
Stock enhancement of inland waters has been conducted since 1967, some of which are obligatory for certain
fisheries. For example, in leasable fisheries, the lessees are obliged to stock seed as recommended by the
government. However, these are often provided by the government, consisting of both suitable indigenous
species to augment the natural recruitment and alien species which are fast growing and capable of utilizing the
food resources in the leased area. The latter species primarily consist of Indian and Chinese major carps, and in
specific instances even tilapia (FAO-NACA, 2003).
Stock enhancement of rivers is regularly conducted using mainly rohu, Labeo rohita, fingerlings of 7 to 10 cm in
length. Such enhancement is conducted on an annual basis, and in certain instances, required fingerlings are
provided at a subsidized price to private owners of water bodies. The water bodies where the activities are mostly
implemented are the main rivers viz: Ayeyarwaddy, Chindwin and their some river locations. In Kachin State, stock
enhancement is mainly conducted in reservoirs and lakes.
The fingerling requirements for stock enhancement purposes are produced in 27 government-owned hatcheries
spreading across the country in different water sheds (Table 3). The fish releasing program is also linked to97
poorly performing broodstocks with frequency of replacement ranging from every one to five years depending
on the hatcheries (Aung et al., 2010). Often, broodstocks of seven or more years old become less productive and
are discarded, and the younger broodstocks are recruited periodically based on this practice. The practices
described above, however, have been undertaken without detailed understanding of the genetic structure of the
species and the impacts of the practices on wild and cultured stocks remain unknown. This process, a practical
experience and welcome strategy, though open to science-based improvement, has avoided inbreeding of stocks
and maintenance of genetic diversity to a very large degree (Aung et al., 2010).
Table 3.  Finfish hatcheries in states and divisions in
Myanmar and the production of seed stock used for
stock enhancement in 2008-2009
Location of hatcheries Numbers
Yangon division 3 178.99
Bago division 3 80.62
Mandalay division 5 303.10
Ayeyarwaddy division 5 120.81
Magway division 2 4.85
Kachin division 2 7.72
Sagaing division 3 31.41
Mon state 1 9.30
Shan state 2 3.59
Kayin state 1 0.31
a program of replenishment of brood stock of the
ma jor   cul tured  spec ies,  in pa r  t i cul a r   rohu  and
mrigal, Cirrhinus cirrhosus. In addition, other species
are also used for stock enhancement purposes of
open waters in Myanmar, these being  Cyprinus
ca rpio, Cat la  ca t la, Ct enophar  yngodon  ide l la,
Hypophthalmicthys molitrix, Tilapia  spp., Puntius
spp., Pangasius hypothalamus etc. Overall, large
number s  of   seed have  been  s to c ked over   the
years to enhance fisheries of open inland waters in
Myanmar (Table 4).
In areas where seed is released, such as along the
Ayeyarwaddy River and associated floodplains,
there is an agreement that fishers should in turn
p ro v i d e   to   t h e   h a t c  h e r i e s   ce  r  t a i n   n umb e r   o f
potential broodstock candidates of major stocked
species such as rohu, mrigal, etc., to partially replace
Table 4.  The number of seed stocked (in millions) in different inland waters of Myanmar over the years.
AR-Ayeyarwaddy River
Numbers stocked
No. of No. Ponds Total
Dams Stocked
1999-2000 2.05 47 25.99 27.8 1.07 – 54.92
2000-2001 126.22 53 34.72 27.48 23.59 – 85.79
2001-2002 134.70 77 34.67 41.59 16.55 – 92.82
2002-2003 159.25 81 38.80 39.05 56.48 – 134.33
2003-2004 178.01 105 109.99 62.27 43.08 3.28 218.63
2004-2005 186.73 164 108.70 63.27 59.76 4.84 236.57
2005-2006 199.06 218 117.79 56.18 25.49 6.17 205.63
2006-2007 214.92 228 85.93 44.38 6.04 6.55 142.90
2007-2008 181.45 219 90.62 80.40 3.18 7.08 181.27
2008-2009 197.10 228 103.17 91.72 3.41 7.10 205.40
2009-2010 (Dec) 182.70 228 110.17 75.98 2.46 7.44 196.06
Source:  DoF, Myanmar
rivers and
In addition to stock enhancement through the release of seed stocks there are other measures that are adopted
for stock enhancement of inland waters. The main such measure is the implementation of closed seasons. All open
fisheries are generally closed during June, July and August to permit spawning and recruitment. However, in
a specific geographic area, closure could be different during the above period. This means that a closed season
can be enforced in selected areas during spawning periods, through the prohibition of fishing in certain areas.
These closed season provisions are enacted under the Fisheries Law of 1991.
The Freshwater Fisheries Law also prohibits some types of destructive fishing and activities which may have
adverse impacts on fish stocks. Specifically, use of explosives and poisons are banned all together as well as some
unspecified methods and equipment. Within a fishing area, it is prohibited to cut undergrowth or light a fire, to
alter the natural flow of water or to cause pollution. The Law also states that “No one shall cultivate agricultural
crops within the boundary of a fisheries creek”.
Impact assessment studies per se on stock enhancement have not been undertaken in Myanmar. However, at least
so far, there was no evidence of negative impacts on the natural fish populations because of stock replenishing
programs in the nation. On the positive side, there are indications of higher catch rates by artisanal fishers in the
villages near rivers. For instance in Inle Lake, grass carp are released on a regular basis to prevent the spread of
aquatic macrophytes, which in turn also serve as feed for grass carp pond culture in the surrounding areas.
Myanmar has been actively engaged in biodiversity conservation practices in inland waters. The leasable fisheries
in flood plain areas are productive. In the same manner, these also are crucial to biodiversity conservation as these
habitats, being the nursery grounds for maintaining the viable populations of indigenous wild stocks. The
government realizing the importance of some leasable fisheries to biodiversity conservation has promulgated
protective measures for these fisheries and transformed these areas to fish sanctuaries. Accordingly, over the years,
the numbers of leasable fisheries has been reduced to 3 453 from 3 474, and are under constant scrutiny by the
Myanmar remains one of the few, if not the only country, in the region that does not have a reservoir fishery. This
decision is based on the fact that development of reservoir fisheries will impact the reservoir catchment
biodiversity, the catchments being under the jurisdiction of the Ministry of Agriculture and Irrigation.
Myanmar also has been active regarding introductions and the movement and use of alien species in fishery and
aquaculture activities. For example, there is a complete ban on the use of the African catfish Clarias gariepinus
including its use in aquaculture and even its sale in popular markets.
Areas in selected waters are being designated as conservation areas and the habitats thereof are often improved
to provide favourable nursery and spawning grounds for selected indigenous species. In addition specific
notifications are enforced for conservation purposes. For example:
 Notification 2/92
This notification prohibits the catching or keeping in captivity of spawners, breeders, and fingerlings
of freshwater fishes in the months of May, June, July and August without permission of Director General
of DOF.
 Notification 2/95 and 3/95
It prohibits the catching, for any purpose, of spawners and fingerlings of the freshwater prawn
Macrobrachium rosenbergii, and M. malcolmsonii in the months of May, June and July, unless permitted
by the Director General of DOF, Myanmar. If caught accidentally these should be released immediately.99
The main constraints encountered in stock enhancement programs in Myanmar are the limitations in seed stock
availability, and particularly for stocking in remote places which are far from the hatcheries. These constraints are
also associated with the cost of transportation and materials needed for effective transportation. In addition
hatcheries may not be able to function at full capacity, particularly when electricity supply is interrupted. The
situation with regard to fry and fingerling availability is further exacerbated by the demand of the aquaculture
sector, which perhaps is witnessing one of the fastest growth rates in the region currently.
Although not a direct constraint it is important to improve public perceptions on the benefits of stock
enhancement and the associated stocking programs, particularly at the implementation sites (release sites). In
this regard there is a need to educate communities on the long term advantages of stock enhancement, and the
basis of implementation of other strategies such as closed seasons, conservation areas, etc.
Much technological advancement is needed to place stock enhancement programs in inland waters in Myanmar
on a firmer footing. For example, a variety of techniques ranging from culture supported capture fisheries to
intensive aquaculture can be used to compensate for declines in fisheries due to overfishing, environmental
changes or inadequacies in the natural ecosystem (Welcomme and Bartley, 1998) and some of these have to be
adopted in Myanmar.
Introduction of the new species to exploit underutilized niches of the food chain and to compensate for loss of
species due to environmental disturbance is needed.
Equally, there is need for engineering of the environment to improve levels of reproduction, shelter, food resources
and vital habitats of the major species in the inland fisheries, as well as eliminate unwanted species that either
compete with or predate upon target species.
So far, there is no evidence to support that stock enhancement strategies have brought about a reduction in
genetic diversity of the wild stocks. There is a need for constant and regular monitoring of this aspect using
modern molecular genetic tools. However, it should be noted that the current practices adopted in Myanmar in
respect of replenishment of broodstocks, though not conducted strictly on a scientific basis, has been lauded as
a good interim strategy which could be improved upon relatively easily with the application of modern scientific
tools and approaches (Aung et al., 2010).
There is an urgent need for improvement of operation and impact assessments in relation to stock enhancement
in inland waters of Myanmar, which has been lagging behind most countries in the region.100
Aung, O., Nguyen, Thuy T.T., Poompuang Supawadee & Kamonrat Wongpathom. 2010. Microsatellite DNA markers
revealed genetic population structure among captive stocks and wild populations of mrigal, Cirrhinus cirrhosus
in Myanmar. Aquaculture, 299, 237-243.
DOF, Myanmar. 2008. Fishery Statistics (2008-2009). Department of fisheries, Myanmar, Yangon, 97 pp.
FAO-NACA. 2003. Myanmar aquaculture and inland fisheries. RAP Publication 2003/18, 62 pp. Welcomme, R.L., Bartley,
D.M., 1998. Current approaches to the enhancement of fisheries. Fisheries anagement and Ecology, 5, 351-382.101
Kishore Kumar Upadhyaya
Directorate of Fisheries Development
E-mail: kishor.upadhyaya@gmail.com
The ecological and biophysical diversity existing in Nepal offers comparative advantages and opportunities
to develop and restore inland fishery resources for livelihood enhancement and poverty alleviation of rural
communities. Through good governance and proper legislative measures it is required to establish improved
environmental protection. Efforts need to target beneficiaries such as disadvantaged and marginalized
ethnic communities with training and awareness raising, appropriate legal instruments; infrastructure
development needs proper mitigation in hydropower generation/irrigation projects, particularly given the
extensive new construction being planned in the future. Protection of biodiversity through scientifically
guided indigenous fish breeding and restocking programs coupled with improved protection of natural
populations is duly considered.
The economic well being of the Nepalese is very closely bound to its natural resources-arable land, water
and forested areas. Nepal is in the process of developing legislation to protect and enhance its inland fishery
resources. The fisheries sector contributes 2.72 percent to the Agricultural Gross Domestic Production (GDP)
with a growth rate of 6.3 percent and contributes 1 percent to its National GDP.
Key words: Inland water bodies, fisher community, alternative livelihood, resource enhancement, conservation
Nepal is a small, mountainous, land locked country with a wide topographical diversity from alluvial plains to
tableland, valleys, hills, mountains and Himalayas. The altitude ranges from 62.5 m to 8 848 m (Mt Everest) above
sea level (MSL). It has a land area of 147 181 km2
 and is divided into three physiographic regions, from south to
north: the Terai plain, the mid-hills and the Himalayas. Mountains and hills make up 83 percent of the area of
Nepal while the Terai occupies only 17 percent. The Himalayas in the north strongly influence the climate of Nepal.
The country may be divided into three climatic zones according to altitude: subtropical in the Terai, temperate
in the hills, and alpine in the mountains. The climate varies little from east to west. Topographical diversity results
in tropical, subtropical climate in Terai where temperature reaches 46ºC to temperate Tundra climate in the
mountains where temperatures remains below freezing point throughout the year.
The economic well being of Nepal is very closely bound to its natural resources-arable land, water and forested
areas. The total population engaged in agriculture has been reported to be 65.7 percent and the contribution
of the agriculture sector to the national economy is 32.8 percent. Agricultural GDP has a growth rate of
2.8 percent in 2004-2005 (GEED, 2005). In fisheries, Nepal is in the process of developing legislation to protect
and enhance its inland fishery resources, athough, the fisheries sector contributes only 2.72 percent to the
Agricultural Gross Domestic Production with a growth rate of 6.3 percent (1 percent of the Country’s GDP).
The present per capita availability of animal protein is very low as compared to standard recommendations of
daily intake. The livestock and dairy subsector alone cannot meet the protein requirements. Fish is an important
alternative source of animal protein as well as a livelihood to many people in Nepal.102
Inland fishery is a time old tradition and only recently that inland waters have been increasingly impounded for
hydropower generation, irrigation and other purposes (De Silva, 1992). Impounding submerges the plains suitable
for human settlement, agricultural and several other uses, impacting the traditional livelihoods of local
communities depending on those lands. Needless to say all these bring about severe and acute social problems
especially in hilly areas where flat land is scarce.
Meanwhile, reservoir-based fisheries and aquaculture have been successful to generate food, income and job
opportunities (Costa-Pierce and Hadikusumah, 1990; Sugunan, 1995; Costa-Pierce, 1998; Gurung et al., 2008).
However, there are limited studies that explicitly explain the role of fisheries and aquaculture on the issue of
resettlement of communities displaced from impoundment. Similarly, cage-fish culture and enclosure culture in
lakes (especially Pokhara valley lakes) have also been successful to provide food, income and job opportunities
for the poor fishermen families (approx. 300 fishers) living around those lakes.
Nepal is endowed with vast inland water resources in the form of rivers, swamps, ponds and irrigated paddy field
which provides about 0.82 million ha (Table 1) or and covers nearly 3 percent of the country’s land. It is estimated
a little over 1 percent of total water resources available have been used so far for fisheries enhancement activities.
The existing water resources and their potential reveal that there is a tremendous scope for expansion of
intensification of fish production in the country.
Table 1.  Estimated water resources in Nepal
Resource Details
Estimated Coverage Potential for
Area (ha) Percent Fisheries (ha)
Natural Waters 401500 48.8 – –
Rivers 395 000 48.0 – –
Lakes 5 000 0.6 3 500 –
Reservoirs 1 500 0.2 78 000 Estimated to be developed
in the future
Village Ponds 6 735 0.8 14 000 Projected to be added
Marginal Swamps 12 500 1.4 12 500
Irrigated paddy Fields 398 000 49.0 100 000 It is increased to 1 million
hectares (2007/08, DoA)
Total 818 500 100
Source:  Directorate of Fisheries Development (DOFD) 2002
2.1 Rivers
There are over 6 000 fast flowing rivers, rivulets and streams in Nepal. The three major river systems in Nepal are
Koshi, Gandaki, and Karnali originating from the Himalayas flowing with significant discharge in the dry season
as well. The medium rivers originate from the Mahabharata range with wide seasonal discharge fluctuation and
there are a large number of minor rivers originating from the Siwalik range with very low flows during the dry
season, all of which finally flows into the Ganges in India. These rivers are rich in aquatic lives, wildlife and
waterfowl; some are tapped for irrigation, fishing and hydropower generation and most are important for
ecological, economic cultural and recreational values. Artisanal and subsistence fishing is common in these rivers.
2.2 Lakes
Lakes in Nepal are glacial, ox-bow and tectonic (Sharma, 1977). The glacial lakes are oligotrophic and other lakes
range from oligotrophic to mesotrophic and some eutrophic as well. To date fisheries enhancement/aquaculture
activities are undertaken in Pokhara valley lakes only.103
2.3 Reservoirs
There are few man-made reservoirs in Nepal, presently only comprising an area of 1 500 ha, and mainly built for
hydropower and irrigation purposes (Pradhan, 1987). In these reservoirs aquaculture experiments are presently
being undertaken. With the growing development of hydropower and irrigation projects, there is considerable
potential for expanded fisheries enhancement.
2.4 Irrigated rice fields
Irrigated paddy fields are expanding due to the development of irrigation facilities using surface and
underground water. This opens opportunities for paddy-cum-fish culture practices throughout the country. These
are temporary form of water bodies only available during monsoon season which is also the time of rice
cultivation in Nepal.
2.5 Marshy low lands, ghols, swamps, irrigations canals, etc.
Marshy lands and swamps serve as excellent habitat for migratory birds, fish, amphibians and mammals as well
serving as rich habitats for high valued flora and fauna, wild rice varieties, etc. Such natural wetlands are necessary
for preserving gene pools of diverse aquatic flora and fauna. Some of them are currently used for fisheries
enhancement/aquaculture development in the far and mid-western regions of Nepal.
Nepal’s location in the centre of the Himalayan range places the country in the transitional zone between the
eastern and western Himalayas. Nepal’s rich biodiversity is a reflection of this unique geographic position as well
as its altitudinal and climatic variations incorporating Palaearctic and Indo-Malayan bio-geographical regions and
major floristic provinces of Asia, creating a unique and rich diversity of life. Although comprising only 0.09 percent
of global land area, Nepal possesses a disproportionately large diversity of flora and fauna at genetic, species and
ecosystem levels.
There are 185 species of fresh water fish found naturally in Nepal. Fishes of Nepal belong to a total of 11 orders,
31 families and 79 genera. Of the 185 species of fish,, eight are endemic to Nepal (Shrestha, 1995), and 34 are
threatened and 61 species are of insufficiently known status. The endemic species include Barilius jalkapoorei,
Schizothoraichthys annandalei, Psilorhynchus pseudecheneis, Pseudeutropius murius bararensis, Lepidocephalichthys
nepalensis and three species of Schizothorax (S nepalensis, S. macrophthalmus and S. raraensis) are endemic to Rara
Lake. Apart from the native species, 11 exotic fish species have been introduced into Nepal mostly for aquaculture.
However, some exotic species such as silver carp (Hypophtalmichthys molitrix), bighead carp (Aristichthys nobilis)
and grass carp (Ctenopharyngodon idella) were introduced into the lakes of Pokhara (Phewa, Begnas and Rupa).
Those lakes are now thriving habitats for those species. Almost all fishes found in Nepal are food fishes for the
local people.
Although capture fisheries from rivers are practiced traditionally, very little is known about fish catches and
production potential of the rivers of Nepal. Most of the studies undertaken have been by hydroelectric projects
with patchy studies carried out on dam sites mostly for environmental impact assessment (EIA) purposes. These
studies provide basic data on limnological and biological characteristics of certain stretches of rivers. To date, EIA
studies have been conducted by Karnali (Himalayan Power Consultants, 1989), Kali Gandaki (Kali Gandaki A
Associates, et al., 1996). Arun (New ERA, 1991), Kabeli (Nepal consult and Hydro Engineering Services, 1998), Budhi
Ganga (METCON Consultant, 1998), Raghughat Khola (WRC, 1998) (Swar and Shrestha, 1998) and Dudhkoshi
(Shrestha and Swar, 1998), Similar studies have been conducted on the Madi River (Ministry of Agriculture, 1994),
Danda Khola River (Ministry of agriculture, 1994), Trishuli River (Masuda and Karki, 1980; and Fisheries Research104
Centre (FRC), Trishuli, 1993 and 1996 and Sunkoshi River (Bisgard and Rangit, 1999, unpublished). In recent years
fisheries surveys have been undertaken in some tributaries of Koshi, Gandaki, Karnali river systems by the
government. Based on these studies the production of fish from capture fisheries is estimated to be 21 500 tonnes
contributing 44 percent to the total fish production in the country (Table 2). Capture fishery yield is decreasing,
however, it is projected that by 2018 overall fish production will have doubled through aquaculture promotion
and conservation. (Fisheries Perspective Plan (FPP), 2000, DOFD).
Table 2.  Production and productivity from capture fisheries
Water Bodies
Area Fish Production Productivity
(ha) (mt) (mt/ha)
Rivers 395 000 7 110 18 kg
Lakes 5 000 850 170 kg
Reservoirs 1 500 385 260 kg
Ghols 11 100 5 990 540 kg
Irrigated Paddy Fields 398 000 7 165 18 kg
Total 818 600 21 500 Contributes 44 %
Source:  DOFD, GoN, 2008
There are approximately 24 groups of ethnic people. Most of them are marginalized and poor dependent on
inland fisheries resources in Nepal. Swar and Fernando (1980) have estimated that more than 20 000 fishers are
actively involved in capture fisheries. In 2005-2006, the Directorate of Fisheries Development (DOFD), estimated
that 106 257 families with 578 036 beneficiaries were actively involved in capture fisheries for their livelihood.
Indigenous fish species are an important component of biodiversity and are valuable genetic resource for the
future generations but unfortunately many of these fishes are threatened due to environmental degradation and
other human activities.
Inland water resources are nature’s precious gift to a nation, often with important social and economic values
based on multi dimensional uses and a shifting priority away from sole dependence on fisheries to include
a variety of other uses. Still fisheries is an important source of food, nutrition and income for its rural people, with
an estimated 2 percent of the population in Nepal being dependent on fisheries and allied activities.
The economic level of people living around natural water bodies, such as rivers, lakes, reservoirs and wetlands
(specially the fishing communities) are typically marginal often with many surviving on very low incomes, which
may trigger the illegal use of the resources. Most of these communities either have very little land or have no
land at all. They are mainly dependent on fishing activities and often engaged as agricultural labors.
Government policy usually gives priority to agricultural activities. For water resource use, priority typically goes
to hydropower generation and irrigation needs. This is true even though the present agriculture policy has made
fisheries a priority program (P1) but in terms of program formulations and implementation it is not so.
As a part of a successful mitigation measure, the example of cage fish culture is an alternative livelihood option
for communities displaced by reservoir impoundment in Kulekhani. In the 1980’s, fisheries and aquaculture were
hardly envisaged during the planning of hydropower projects. Here, the government of Nepal and International
Development Research Centre (IDRC), Canada jointly demonstrated that cage fish culture in the reservoir is
a promising alternative livelihood option for displaced communities. Among 500 families displaced in 1982 due
to impoundment, nearly 81 percent adopted cage farming and 231 families are now engaged in fish production105
from the reservoir. These families are organized in 11 groups and produce approximately 165 tonnes of fish
(2005-2006) out of which 130 tonnes from cage culture fisheries (80 000 m3
) and rest from open water stocking
and harvesting.
Human interference has effected fish populations and production in many natural water bodies. These are
constant threats to the maintenance of fishery resources and aquatic biodiversity, even though, the government
of Nepal has formulated rules, regulations, plans and policies to counter these threats, very little success has been
achieved so far.
6.1  E f  fe  c  t   o f   imp o u n dme n t   o n   t h e   i n d i g e n o u s   f i s h e s   i n   Ku l e k  h a n i   r e s e r  vo i r
The first documented survey of fish species composition of the stretch of the Kulekhani River now occupied by
Indrasarobar was conducted in 1980 (Shrestha et. al., unpublished). It was reported that Cyprinidae were the most
abundant family, represented by Garra lamta, Neolissochilus hexagonolepis, S. richardsoni, Puntius chilinoides, P. ticto
and P. spp. The families Cobitidae and Channidae were represented by Noemacheilus spp. and Channa orientalis
respectively. The family Sisoridae was represented by Glyptosternum spp. and Coraglanis spp. A survey of the fish
fauna of the Kulekhani River upstream of the reservoir revealed that Cyprinidae were the most abundant family
followed in order of abundance by Sisoridae, Cobitidae and Channidae (Pradhan, 1986). A further comprehensive
investigation of the fish populations in Indrasarobar Reservoir from January 1985 to June 1989 examined the
impacts of the construction of the Kulekhani dam and the conversion of 7 km of the river into a lake. This
transformed a varied but unstable riverine environment into a relatively stable lacustrine one although subject
to extensive drawdown. A profound change in the relative abundance of many species occurred within a short
time of the lake’s formation (Swar, 1992; 1994). These changes included:
 A drastic decline in the number of snow trout S. richardsoni;
 The disappearance of  Puntius spp., G. lamta, Neomacheilus spp.,  C. gachua, Glyptosternum spp. and
Coraglanis spp.
 Two indigenous species, N. hexagonolepis (katle) and P. chilinoides (karange) remained dominant.
 Three species H. molitrix, silver carp;  A. nobilis, bighead carp and  Tor tor, mahaseer which were not
native to the Kulekhani River, appeared in the catches of 1986/87. They formed a considerable
percentage of the catches in 1987/88 and 1988/89. These species were not deliberately introduced in
the open water, but escaped from cages.
Table 3.  Changes in fish species in Indrasarobar Reservoir, Nepal from 1980 to 1989 (Swar, 1992).
Introduced Disappeared Dwindled Now dominant
T. tor G. lamta S. Richardsoni N. hexagonolepis
A. nobilis P. ticto P. chilinoides
H. molitrix Puntius spp.
Neomacheilus spp.
C. gachus
Glyptosternum spp.
Coraglanis spp.
6.2 Conservation strategies
Conservation aims to maintain genetic biodiversity at present and in future and seek to provide a regular supply
of aquatic products for human consumption. Increasing efforts are being made for effective implementation of
“community water bodies” and awareness of aquatic life protection act and rehabilitation of depleted fishes by106
stocking with hatchery produced seed of important indigenous species. At the same time, implementation of
a new policy to manage the import of exotic fish species is also tried. Conservation of fish through participatory
management is emphasized, including the conducting of training and awareness programs. Similarly, improved
monitoring of the environment coupled with the provision of alternative livelihood activities like aquaculture for
displaced as well as affected people is being expanded in various areas.
6.3 Water Resources Strategy (WRS)
For decades, Nepal’s economic development efforts have focused on its water resources. Although the country
has an abundance of water in terms of annual surface flow and groundwater reserves, the progress towards
utilization of this water for basic uses and economic growth has been slow. In recognition of this fact, the
Government of Nepal prepared a long-term Water Resources Strategy, capable of guiding water sector activities
towards sustainability of the resource, while providing for hazard mitigation, environmental protection, economic
growth and constructive methods of resolving water use conflicts. The main objectives of the WRS are:
1. Every Nepali citizen, now and in the future, should have access to safe water for drinking and
appropriate sanitation, as well as enough water to produce food and energy at reasonable cost.
2. Nepal needs to promote ways of managing its water at the river basin level to achieve long-term
sustainability for the benefit of its entire people. This will require a holistic, systematic approach that
honors, respects and adheres to the principles of integrated water resources management.
6.4 National Water Plan (2005)
In order to implement the activities identified by the Water Resources Strategy (WRS), the Government of Nepal
approved the National Water Plan 1 (NWP), in 2005. The NWP1 recognizes the broad objectives of the WRS and
lays down short, medium and long-term action plans for the water resources sector, including investments and
human resource development. The NWP1 attempts to address environmental concerns, which are reflected by
the incorporation of the Environmental Management Plan in the document. This Environmental Management Plan
will contribute to maximizing positive impacts and minimizing or mitigating adverse impacts in line with
environment sustainability concerns. Two component of the NWP1 are particularly relevant here.
6.4.1 Management of watersheds and aquatic ecosystem
The targets in this sub-sector as mentioned in the NWP are:
 By 2007: A management plan for nationally important watersheds and aquatic system is prepared and
initiated and water quality and wastewater quality standards are developed and enforced.
 By 2017: Full scale environmental protection and management projects are implemented in all priority
watersheds and aquatic ecosystems and stakeholders’ participation in environmental protection and
management is provided for.
 By 2027: Quality of watersheds is increased by 80 percent in all regions and adequate water quality is
attained for aquatic habitat, including fish, human consumption and recreation in all rivers and lakes.
The following action programs are detailed out for the purpose of achieving the targets mentioned above:
 improve environmental database system;
 map important, critical and priority watersheds and aquatic ecosystems;
 develop and implement water and wastewater quality standards and regulations;
 implement nationally important watersheds and aquatic ecosystems protection, rehabilitation and
management programs;107
 implement water conservation education program;
 develop strategic environmental assessment in water resources management;
 ensure compliance of EIA;
 promote community participation in the management of watersheds and aquatic ecosystems;
 enhance institutional capacity and coordination; and
 develop watershed management policy
6.4.2 River basin management
Similarly for the River Basin management, the following action programs are detailed out in NWP:
 Mainstreaming Inland Water Resource Management (IWRM) and the river basin concept
 Development of river basin plans
 Development and implementation of Decision Support System (DSS) in water resources programs
 Establishment as well as strengthening of institutions for river basin planning
6.4.3 Agencies involved in conservation and management
The main organizations actively involved in the management of IWRM/wetlands are:
GOVERNMENT AGENCIES: Ministry of Environment, Water Resources, Forest and Soil Conservation,
Agriculture and Co-operatives (Directorate of Fisheries Development) and the National Planning
AUTONOMOUS BODIES: Water and Energy Commission, Environment Protection Council, Nepal Agriculture
Research Council, Nepal Academy of Science and Technology, Tribhuvan University Kathmandu University,
Nepal Electricity Authority.
INGO’S AND DONOR AGENCIES: Finnida, Care Nepal, JICA, IUCN – The world conservation union, Asian
Wetland Bureau, International Crane Foundation, Worldwide Fund for Nature, Asian Development Bank.
NON-GOVERNMENT ORGANIZATIONS: King Mahendra Trust for Nature Conservation, Nepal Bird Watching
Club, Save Bagmati Campaign, Save Phewa Lake, Nepal Heritage Society, Nepal Nature Conservation Society,
Association for Protection of Environment and Culture.
PROFESSIONAL ORGANIZATIONS: Nepal Fisheries Society, Informal Wetland Group, Institute of Biodiversity
of Nepal (IBN), Nepal Botanical Society, Nepal zoological Society, Natural History Society of Nepal, Cultural
Green Club etc.
6.5 Existing conservation and mitigation measures
In response to the growing global awareness about the importance of maintaining a balance between economic
development and environmental conservation, the Nepal Environmental Policy and Action Plan (NEPAP) has been
launched. NEPAP is a part of the Government’s continuing effort to incorporate environmental concerns into the
country development process. Efficient and sustainable management of natural and physical resources and
mitigating the adverse environmental impacts of development projects and human action are the main themes
of NEPAP. Conservation of fishery resources is part and parcel of the broad NEPAP. National wetland policy and
strategic plan for biodiversity conservation has also been prepared by Government of Nepal in order to protect
aquatic resources. National wetland policy is based on local people’s participation. It aims to conserve and
manage aquatic resources with local people’s participation for their benefit, while maintaining environmental
integrity. At the same time, it also aims at wise use of wetland resources by providing equal opportunities on the108
basis of local people’s participatory management of wetlands to conserve natural resources for the benefit of
present and future generations. Similarly, the strategic plan for biodiversity conservation aims at conserving
biological diversity and the sustainable use of its components and ecosystems. The following measures have been
carried out to till now to conserve fisheries resource in Nepalese water systems.
6.5.1 Legislative arrangements
Conservation of aquatic life is addressed by the Aquatic Animal Protection Act (AAPA) 2017/1961, which prohibits
the use of explosive or poisonous substances in any water body where the intention is to catch or kill aquatic
life. The Government of Nepal has formulated aquatic life protection regulation and the procedure of its
implementation. It regulates fishing gears, size of the fish and season. Examination of the impacts of development
projects on fishery resources and implementation of mitigation measures has been made mandatory under this
regulation. Along with AAPA there is legislation impacting Wetland Biodiversity and Ecosystem Conservation in
Nepal such as the Forest Act, and a similar set of Acts covering environmental protection, national parks and
wildlife protection soil and watershed conservation, and related issues.
6.5.2 Environmental impact assessments
After the implementation of the NEPAP, Nepal has introduced legal or institutional mechanisms for the use of EIA.
Different EIA reports recorded fish species (for example see the list of aquatic flora and fauna as given in
Annex 1). Impacts of development projects on aquatic life are thoroughly assessed and mitigation measures
established, such as the establishment of a fish hatchery and recommendation for fish trapping and hauling,
restocking fingerlings activities under Kali Gandaki “A” Hydropower Project.
6.5.3 Establishment of fish sanctuaries
The majority of fish inhabiting rivers are extremely sensitive to environmental changes that occur in modified
rivers. An extensive network of protected areas has now been established in Nepal. Nepal has nine national parks,
three wildlife reserves and one hunting reserve, four conservation areas, eleven buffer zones covering an area of
28 998 km2
 (19.7 percent of the country’s total area). Similarly, nine water bodies with an area of 34 455 ha have
been declared as Ramsar sites.
6.5.4 Protections of endangered species
Table 4.  Status of fish species in Nepal
(adapted from Shrestha, 1995)
Status Number
Common/occasional 90
Insufficiently known 61
Vulnerable 9
Endangered 1
Rare 24
Total 185
The present status of fish species (based on an older account
listing 185 species) were given in Table 3. Native fish species
recommended for legal protection are listed in Table 4. One
spec ies   (Tor tor)   i s   l i s ted  a s  endangered whi le 9  spec ies   a s
There are twenty six mammals, nine birds and three reptiles listed
as threatened species in Nepal. However, until now none of the
fish species has been included in the list of IUCN.
6.5.5 Promulgation of aquatic animal protection regulations
The Aquatic Animal Protection Act (AAPA) was passed in 1961; in 1999 the Government promulgated the AAPA
regulations. The guidance, policies, and experience related to the development of fisheries have now been
defined. In the past fisheries in inland water bodies have often been subject to ecological damage from poisoning,
bombing, poaching and stealing of fish. In order to protect national interests and the legal rights of fishermen,
the law defines concrete administrative penalties, civil liabilities and responsibilities. However, its implementation
is far from satisfactory.109
6.5.6 Fish trapping and hauling
Fish trapping and hauling is another alternative for assisting natural fish migration. Fish trapping can be used for
a variety of fish species and sizes. Migratory species can be captured and hauled. However, there are drawbacks
to the fish trapping and hauling approach; stress related mortalities may occur. Risk of poaching may be another
disadvantage. However, fish trapping and hauling has been recommended at Kali Gandaki “A” Hydroelectric
Project. However, it has not yet been practiced.
6.5.7 Fish ladders
One of the remedies commonly proposed for blockages to migrations caused by dams is the construction of fish
passes or ladders. Most of the existing and proposed water development projects in Nepal do not have fish
passes. Although almost all the prominent rivers of Nepal are dammed for various development purposes, there
are only a few examples of fish ladders (e.g., Koshi Barrage; Chandra Nahar in Trijuga; Andhi Khola, Gandak
Barrage). However, little data is available on fish ladder performance. The fish ladder in the Trijuga River is not in
operational condition due to the lack of maintenance and inappropriate design. In the Koshi Barrage the upper
chambers of the ladder are frequently used as fish traps for illegal harvesting by local fishers (D.B. Swar, personal
6.5.8 Fish hatcheries
Establishment of fish hatcheries is another measure for mitigating the impact of a dam building on the native
fish fauna. Hatcheries can play an important role in fish conservation and management in developing countries.
In recent years, their efficiency has increased with better knowledge of the biological and reproductive
requirements of fish while other issues such as genetics remain controversial. A fish hatchery was established at
Kali Gandaki “A” Hydropower Project. The main objective of the hatchery is to propagate mahseer (Tor putitora),
katle (N. hexagonolepis), snow trout (S. richardsonii); jalkapoor (C. garua) and other important native fish species
affected by the construction of the dam. However, to date only six out of fifty-four species reported from the Kali
Gandaki River are being bred.
6.5.9 Open water stocking
Among the indigenous fish species of Nepal, N. hexagonolepis (katle), Labeo spp., T. Tor, T. putitora (sahar, mahseer
or mahaseer), and S. richardsonii, S. progastus (snow trout or asala) have been identified as important for sport
fishery as well as being excellent food fish. Their domestication started in the 1970s. Fish fry are being produced
in hatcheries and trials are going on to culture them in captivity. Seeds of these species are released in various
rivers, lakes and reservoirs but the impact assessment is not properly done.
Table 5.  List of species recommended for legal protection under the AAP regulation
Scientific name Common name NRDB code Distribution
Neolissocheilus hexagonolepis Katle V Koshi, Gandaki, Karnali, Mahakali
Chagunius chagunio Rewa V Koshi, Gandaki, Karnali, Mahakali
Tor putitora Mahseer V Koshi, Gandaki, Karnali
Tor tor Sahar E Gandaki, Mahakali
Danio rerio Zebra macha V Gandaki, Karnali
Schizothorax plagiostomus Buchhe asla V Koshi, Bheri, Gandaki, Karnali, Mahakali,
Phewa, Lake, Gandaki
Schizothorax richardsonii Asala soal V Koshi, Gandaki, Karnali
Schizothoraichthys progastus Chuche asala V Koshi, Gandaki, Karnali
Psilorhynchus pseudecheneis Tite macha V Koshi
Anguilla bengalensis Rajabam V Koshi, Gandaki, Karnali
V = Vulnerable; E = Endangered110
6.5.10 Awareness programmes
The Government of Nepal through the Directorate of Fisheries Development has started awareness programmes
in highly affected areas by using participatory methods with concerned/affected people including putting up
public notice (hoarding boards) at various locations.
Nepal is in the process of developing legislation to protect and enhance its fisheries and aquatic resources. Very
little has been done in terms of fisheries resource enhancement and conservation. The major constraints include:
1. Lack of adequate legal instruments to reduce loss of its rich biodiversity (note that new regulations
under Aquatic Animal Protection Act, 1961 are in the process of formulation and execution by Nepal
Government) due to urbanization, encroachment, construction of large hydro-dams/barrages/roads,
sand and gravels/boulders mining, and illegal fishing.
2. Although, Inland water fishing is very popular and has great potential in Nepal; the present status of
fisheries resources are not known due to absence of adequate scientific and data which prevents
sustainable use of the available resources.
3. Absence of coordination among various government and other agencies involved in inland water
resource use; lack of integrated land and water resources use planning.
4. Low levels of public awareness and participation in resource enhancement, development and
5. Limited technical capabilities, infrastructure facilities and human resources development.
The ecological and biophysical diversity existing in Nepal offers comparative advantages and opportunities for
developing and restoring inland fishery resources for livelihood enhancement and poverty alleviation of rural
communities. Improved environmental protection is required. Efforts need to target beneficiaries such as
disadvantaged and marginalized ethnic communities with training and awareness raising, appropriate legal
instruments; infrastructure development needs proper mitigation in hydropower generation/irrigation projects,
particularly given the extensive new construction being planned in the future and as well as the protection of
biodiversity through scientifically guided indigenous fish breeding and restocking programmes coupled with
improved protection of natural populations. Specific recommendations for a sound inland resources/fisheries
management include:
 Base line data development: Prioritizing accessible and important water bodies, development of tools
for systematic and comprehensive collection of fisheries statistics.
 Improved Governance: Establishment of a National Water Resource Development and Conservation
Committee at the national level to adopt and implement a cleat cut policy for natural water
conservation and utilization.
 Moni tor ing  and  E va lua t ion:  S t r i c  t   and per iodi c  moni tor ing  and eva lua t ion of   the  impa c  t  of
enhancement activities are suggested to be carried out by independent bodies.
 Capacity building including institutional development and/or strengthening: Facilitate the preparation
and/or implementation of national strategies, plans for priority programmes and activities for
conservation of biological diversity and sustainable use of its components.
 Participatory valuation: At present, the rivers of Nepal are utilized either for generating hydroelectric
power or for irrigation purposes only, with little consideration being given to their fisheries value. For
the conservation of the freshwater fishery resources it is important to involve fisheries professionals
and local communities in the planning and feasibility studies.111
 Regional cooperative effort: It is suggested among the countries of the Trans-Himalayan region that
share many important inland water and fishery resources.
 User involvement: Identification of critical habitat and protection measures needs to embrace
community participation, protection of rights of users and exact legislation for the conservation and
sustainable use of Inland Water Resources more generally.
 Improved control measures: Sanctuaries and/or no fishing zones, closed-seasons, control on illegal
fishing and use of gears needs greater priority particularly to protect indigenous threatened species.
Political Will: increased support from decision makers will be crucial to all of the above.112
Country Profile-Nepal. 2008/09. Directorate of Fisheries Development, Central Fisheries Building, Kathmandu, Nepal.
Cernea M.M. 1997. Hydropower dams and social impacts: A sociological perspective. Environmentally Sustainable
Development (ESD). The World Bank. pp 1-37.
Costa-Pierce B.A. and H.Y. Hadikusumah. 1990. Research on reservoir-based cage aquaculture systems in Saguling
Reservoir, West Java, Indonesia. In: Costa-Pierce, B.A. and O. Soemarwoto (eds.). Reservoir fisheries and aquaculture
development for resettlement in Indonesia. ICLARM, Technical Report 23. International Centre for Living Aquatic
Resources Management (ICLARM), Manila.
Gubhaju, S.R. 2001. Impact of Damming on the Aquatic Fauna in Rivers. Paper presented at “Symposium on Cold Water
Fishes of the Trans-Himalayan Region. 10-13 July, 2001. Kathmandu, Nepal.
Tek B. Gurung, Raja M. Mulmi, Kalyan K.C., G. Wagle, Gagan B. Pradhan, K. Upadhyaya & Ash K. Rai. 2008. The success on
adoption of cage fish culture as an alternative livelihood option for communities displaced by reservoir
impounded in Kulekhani, Nepal.
IUCN. 1994. Proceedings of the National Workshop on Wetlands Management in Nepal.
National Wetland Policy, 2003. Ministry of Forests and Soil Conservation, Government of Nepal, Singhdurbar, Kathmandu.
Nepal Bio-diversity Strategy, 2002. Ministry of Forest and Soil Conservation, Government of Nepal.
Pradhan, B.R. 1987. Potential of reservoirs fishery development in Nepal. IDRC Workshop Proceedings.
Sharma, C.K. 1977. River systems of Nepal. Kathmandu: P.P.W. Ltd.
Sharma, C.K. 1997. A treatise on water resources of Nepal. P.P.W. Ltd.
Swar, D.B. 2001, The Status of Cold Water Fish and Fisheries in Nepal and prospects of Their Utilization for Poverty
Reduction. Paper presented at “Symposium on Cold Water Fishes of the Trans-Himalayan Region. 10-13 July 2001.
Kathmandu, Nepal.
Swar, D.B. & C.H. Fernando. 1980. Some studies on the ecology of limnetic crustacean zooplankton in lake Begnas and
Rupa of Pokhara Valley, Nepal. Hydrobiologia 70: 235.
Swar, D.B., G.B.N. Pradhan & L.M. Lofvall Westlund (Eds.). 1997. Proceedings of the National Symposium on the Role of
Fisheries and Aquaculture in the Economic Development of Rural Nepal, 1996, 15-16 August. Kathmandu, NEFIS,
Sugunan V.V. 1995. Reservoir fisheries of India. FAO Fisheries Technical Paper. No. 345. Rome, FAO. 423 p.
Swar D.B. 1992. Effect of impoundment on indigenous fish population in Indrasarobar Reservoir, Nepal. Proceedings of
the second Workshop on Reservoir Fishery Management in Asia (S.S. De Silva (ed.). IDRC, Ottawa, 111-118.
Swar D.B. & T.B. Gurung. 1988. Introduction and cage culture of exotic carps and their impact on fish harvested in Lake
Begnas, Nepal. Hydrobiologia 166: 277-283.
Swar D.B. & B.R. Pradhan. 1992. Cage fish culture in lakes of Pokhara Valley, Nepal, and its impact on local fishers. Asian
Fisheries Science 5: 1-13.113
Upali S. Amarasinghe
Department of Zoology, University of Kelaniya, Kelaniya GQ 11600, Sri Lanka
E-mail: zoousa@kln.ac.lk
Early attempts of fisheries enhancement in Sri Lankan freshwaters were aimed at establishing commercial
fisheries and consequently, exotic cichlid species were introduced during the second half of the last century.
A fisheries enhancement strategy was introduced to village reservoirs of the country in 1980s on a trial basis.
This is termed as culture-based fisheries (CBF), which combines elements of aquaculture and capture
fisheries and relies entirely on the natural productivity of the water body for growth of fish, and on artificial
stocking as a means of recruitment. These efforts were however, unsuccessful under the technological and
sociological milieu that prevailed, and further aggravated after the discontinuation of state patronage for
inland fisheries and aquaculture development in Sri Lanka during 1990-1994.
Presently, inland fisheries enhancement strategies in Sri Lanka are practiced in seasonal reservoirs and minor
perennial reservoirs. The annual CBF production from these reservoirs is about 6 600 tonnes, accounting for
about 17 percent of the inland fisheries production. The aquaculture extension officers of National
Aquaculture Development Authority (NAQDA) and several NGOs have been conducting awareness
programs to educate rural farmers on CBF management and development of business plans, facilitating
inland fisheries resources enhancement in the country.
The major seed resources for fisheries enhancement are fingerlings of Chinese and Indian major carps.
State-owned aquaculture development centres (AQDCs) of NAQDA are responsible for induced breeding
and rearing of post-larvae to fry stage. Community-based organizations (CBOs) and private pond owners
have a significant role in fingerling rearing for fisheries enhancement.
Although there has been a significant policy developments providing legal provisions for fisheries and
aquaculture development in small reservoirs, in some parts of the country, CBF activity is still considered
as a secondary use of reservoirs with low priority. Furthermore, possible impacts of fisheries enhancement
on the biodiversity of native flora and fauna cannot be completely ignored and as such a procedure for
impact assessment should be introduced. The provincial and central government fisheries authorities can
play the role of project proponent and as part of the extension mechanism, for conducting EIAs or IEEs.
Key words: Culture-based fisheries; cichlidae; Chinese carps; Indian carps; introduced fish; stocking strategies;
tropical reservoirs
In some Asian countries such as Sri Lanka, reservoir construction was an integral part of ancient civilization. The
sovereignty of ancient hydraulic civilization in Sri Lanka is witnessed by extant reservoirs some of which have
been as old as 2000 years (Brohier, 1934, 1937; Fernando and De Silva, 1984; De Silva, 1988). The rural communities
in Sri Lanka have traditionally developed various management practices leading to sustainable utilization of
fishery resources in village irrigation systems (Siriweera, 1994; Ulluwishewa, 1995). In the past, fish production from
inland reservoirs was based on indigenous species and there was no commercial scale inland fishing in ancient
Sri Lanka. In reservoirs, there are great opportunities for improved fish production from enhancement of natural
production (Petr, 1994, 1998; Lorenzen et al., 2001). Fisheries enhancements are defined as limited technological
interventions in the life cycle of common pool aquatic resources (Lorenzen et al., 2001). The present review is
essentially based on this definition.114
Enhancement strategies are implemented in the existing water bodies, mainly inhabited by indigenous fish
species. Through the enhancement strategies, conservation efforts should not be compromised especially because
Sri Lanka is one of the biodiversity hotspots of the world (Bossuyt et al., 2004). Being a country with high degree
of endemism in the freshwater fauna, sufficient legal provisions exist in the Fisheries and Aquatic Resources Act
of Sri Lanka (Anon., 1996a), for the conservation of aquatic organisms. Accordingly, conservation areas can be
declared to afford special protection to the aquatic resources in danger of extinction in such waters or land and
to protect and preserve the natural breeding grounds and habitat of fish and other aquatic animals.
1.1 History of inland fisheries resource enhancement and conservation
A commercial scale inland fishery of Sri Lanka is essentially a post-1950 development in major reservoirs of the
island, and occurred after the introduction of Oreochromis mossambicus (Fernando and Indrasena, 1969; Fernando
and De Silva, 1984; De Silva, 1988). Presently, contribution of inland fish production to the total national fish
production is in the range of 9-14 percent (Figure 1).
Figure 1.  Annual fish production in Sri Lanka from different sub-sectors (2000-2008)
50 000
100 000
150 000
200 000
250 000
300 000
350 000
2000 2001 2002 2003 2004 2005 2006 2007 2008
Inland and Aquaculture Offshore/Deep sea Coastal
Fish production (metric tonnes)
The inland capture fisheries are primarily from major irrigation and hydroelectric reservoirs (>750 ha) and the
total extent of such reservoirs is about 70 000 ha (about 42 percent of the total extent of lentic water bodies).
Small-scale fisheries exist in the medium-scale reservoirs (250-750 ha), which form about 10 percent of the total.
The minor irrigation reservoirs (<250 ha), generally referred to as “village tanks” with a cumulative extent of about
39 000 ha, can be categorized into two groups depending on the water retention period. Those that retain water
throughout the year are called “minor perennial reservoirs” and those which retain water for 7-9 months each year
are locally known as “seasonal reservoirs” or “non-perennial reservoirs” (Mendis, 1977; Thayaparan, 1982). In the
minor perennial reservoirs, subsistence level fisheries exist (Murray et al., 2001; Pushpalatha and Chandrasoma,
2010). The non-perennial reservoirs are small (<60 ha) and are largely rain-fed (from inter-monsoonal rains from
October to January). They tend to be eutrophic due to the addition of nutrients from the catchment areas. These
village reservoirs were thought to be used as ‘fish ponds’ for stocking of fish fingerlings after filling with water
from the inter-monsoonal rains. A number of attempts were made to utilise these waters for fish production over
the years through stock enhancement (Anon., 1964; Indrasena, 1964, 1965; Fernando and Ellepola, 1969). This
enhancement strategy termed as culture-based fisheries (CBF) was suggested to be managed by the rural
communities, whose livelihoods were dependent on reservoirs for irrigation of agricultural lands, watering their
cattle and buffaloes and domestic uses (Mendis, 1977). CBF combines elements of aquaculture and capture
fisheries and relies entirely on the natural productivity of the water body for growth of fish, and on artificial
stocking as a means of recruitment (Lorenzen, 1995). In CBF, hatchery reared fish are released into water bodies
not primarily managed for fish production, and are recaptured upon reaching a desirable size (De Silva, 2003).115
CBF development in village reservoirs was incorporated in the national fisheries development plan of the country
(Rosenthal, 1979; Oglesby, 1981), and pilot scale projects were initiated in the early 1980s (FAO/UNDP, 1980;
Thayaparan, 1982). From these CBF trials, yields ranging from 220 to 2 300 kg ha
 in 15 seasonal reservoirs (mean
892 kg ha
) within a growing season were reported (Chandrasoma and Kumarasiri, 1986).
In spite of the high potential for the development of CBF in village reservoirs, the program did not sustain itself.
De Silva (2003) mentioned the likely reasons for the overall failure of the strategy as follows:
 lack of a guaranteed fingerling supply, which frustrated the stakeholders, as at times tanks were
under-stocked or were unable to be stocked to make use of the growing season fully;
 oversupply of fish supply in the market both in space and time;
 rules and regulations, and responsibilities of stakeholder organizations were not well thought out
and/or planned; and
 supply of undersized fingerlings resulting in low returns, which brought about a disinterest in the future
of the program.
Furthermore, a politically inspired withdrawal of state patronage for the development of the inland fisheries sector
from 1990 to 1994 was also a major setback to the development of CBF (De Silva, 1991; Amarasinghe, 1998),
because this activity was highly dependent on state subsidies for fingerling supply. The lack of guaranteed
f inger l ing  suppl y   f rom  the gove r nment  hat cher ies, whi ch we re   lea sed out   to   the pr i va te  sec  tor   a f  te r
discontinuation of government support in 1990 brought about a general collapse of CBF development activities
in village reservoirs.
It is generally believed that introduced fish species pose threats to the biodiversity. In fact, O. mossambicus,
the mainstay of the inland fishery of Sri Lanka is labelled as one of the worst invasive alien species in the world
(Lowe et al., 2000). In Sri Lankan freshwaters however, clear habitat segregations are evident in indigenous and
endemic freshwater fish species that inhabit in rivers and streams of higher elevations (Moyle and Senanayake,
1984; Kortmulder, 1987; Wikramanayake and Moyle, 1989) whereas the exotic cichlids have colonized lacustrine
habitats of reservoirs and slow-flowing, isolated habitats in a few streams (Amarasinghe et al., 2006). Due to this
habitat segregation, any adverse effect of the exotic cichlids species on the diversity of indigenous freshwater
is unlikely (Fernando et al., 2002; Amarasinghe et al., 2008).
1.2 Major practices of fisheries resource enhancement and management
As mentioned above, major practices of inland fisheries enhancement in Sri Lanka until early 1980s were of
ad hoc nature and involved in introduction of exotic species into Sri Lankan reservoirs. Many reports on stocking
of reservoirs are available, for example, Chinese and Indian major carps and O. niloticus (Jayasekara, 1989), L. rohita
(Chandrasoma, 1992). However, when a broad database was used fish yields of exotic carp species showed
a negative curvilinear relationship with the reservoir area, indicating that high fish yields through stocking can
only be achieved in small (<800 ha) reservoirs (Amarasinghe, 1998), as demonstrated for elsewhere in the world.
(De Silva et al., 1992; Sugunan, 1995; Welcomme and Bartley, 1998).
The early phase of capture fisheries development in Sri Lankan waters during the second half of the twentieth
century can be considered as a fisheries enhancement approach because introduction and stocking of exotic fish
species played a major role in the development strategy. As the capture fisheries in major perennial reservoirs
are managed mainly for self-recruiting tilapias, which have been well established, now account for over 90 percent
of the landings (Amarasinghe, 1998). As such, established profitable capture fishery in major perennial reservoirs
of Sri Lanka does not have the features of enhancement, as defined by Lorenzen  et al. (2001). However since
January 2009, the government has initiated subsidized stocking of fingerlings in all reservoirs including major
perennial reservoirs (see below). Nevertheless, the outcomes of these stocking regimes remain to be evaluated.
After the general collapse of the major enhancement program, in village reservoirs in the 1980s for the reasons
mentioned above, several attempts were made in mid 1990s for CBF development. For example, under a project116
funded by Australian Centre for International Agricultural Research (ACIAR), a research team from the University
of Kelaniya and National Aquaculture Development Authority of Sri Lanka in collaboration with Deakin University,
Australia, has carried out an extensive study in 47 village reservoirs in five administrative districts of Sri Lanka,
focusing on developing holistic management strategies for CBF in village reservoirs incorporating biological,
physical, and socio-economic factors.
Until the 1980s, the general practice was to produce fingerlings in state-owned hatcheries and as such, the limited
pond space in those hatcheries was major setback for supplying sufficient numbers of fingerlings. This situation
was aggravated after the government-owned fish breeding centres were leased out to the private sector in 1990.
However, after the revival of state patronage for inland fisheries and aquaculture development in 1994, fingerling
production for stocking inland water bodies through community participation was recognized as a feasible
strategy. Induced breeding and rearing of post-larvae up to fry stage (2-3 cm in size) were recognized as the
purview of government hatcheries. Also, extension mechanism in the inland fisheries and aquaculture sub-sector
was strengthened (Amarasinghe, 1998). NAQDA was established under a Parliamentary Act in 1998 (Anon., 1998a;
Anon., 2006a) as the responsible agency for the development of inland fisheries and aquaculture in the country.
1.3 Fish species cultured
In Sri Lankan indigenous fish fauna, fast-growing fish species which feed on lower trophic levels are absent and
as such, there is a heavy reliance on exotic species for inland fisheries enhancement strategies. Hatchery-produced
fingerlings of catla (Catla catla), rohu (Labeo rohita), mrigal (Cirrhinus mrigala), bighead carp (Aristichthys nobilis),
common carp (Cyprinus carpio) silver carp (Hypophthalmichthys molitrix), grass carp (Ctenopharyngodon idella) are
generally stocked in seasonal reservoirs and minor perennial reservoirs. In addition, Nile tilapia (O. niloticus) GIFT
(genetically improved farmed tilapia) strain of O. niloticus and freshwater prawn (Macrobrachium rosenbergii)
are stocked by some community-based organizations (CBOs). Wijenayake et al. (2007) have however, shown that
GIFT strain on Nile tilapia is not suitable for fisheries enhancement through CBF in village reservoirs of Sri Lanka
because they showed poor growth performance perhaps due to their inability to compete with other stocked
species for natural food. As density-dependent factors also influence the CBF yields, a positive second order
relationship was evident between stocking density and yield (Wijenayake et al., 2005). Accordingly, the optimal
stocking density of major carps (stocking size of 5-6 cm) was found to be about 3 500 fingerlings/ha.
In small reservoirs which are utilized for CBF development, especially those which do not dry completely in the
dry season, naturally recruiting carnivorous fish species from the associated water ways such as Ophicephalus
striatus, Mystus keletius and Anabas testudineus also influence performance of stocked species in the CBF. In such
reservoirs, CBF harvests of stocked species are low due to predation (Wijenayake et al., 2005). In 1980s during the
pilot-scale CBF trials, these undesired species were eradicated by adding biodegradable substances such as
bleaching powder before stocking reservoirs (De Silva, 1988). From the point of view of biodiversity conservation,
stocking of large (>10 cm) fingerlings is advisable.
1.4 Scale of operation
Inland fisheries enhancement in Sri Lanka comes under the purview of NAQDA. The Aquatic Resources
Development and Quality Improvement Project (ARDQIP), funded by Asian Development Bank from 2003 to 2009
has been instrumental in implementing inland fisheries enhancement strategies in the country. The ARDQIP
supports aquatic resource development and quality improvement to enhance food security and reduce poverty,
especially in rural areas of Sri Lanka. The project assists NAQDA to build its technical and financial capacity to
support aquaculture development, and to become a financially self-sustaining organization.
The current stocking strategies in reservoirs are supposedly driven by the desires of resource users. For example,
in large and medium-sized reservoirs, stocking is carried out guided the complaints by reservoir fishers about the
status of the fisheries. As mentioned by Cowx (1998), fishers’ complaints about the status of the fishery might not
be accurate because such trends may be due to natural production cycles and as such, long-term beneficial
effects of stocking in such water bodies are unlikely. Details on the stock enhancements in 2007/08 in relation
to the type of water body are summarised in Table 1.117
CBF development in seasonal reservoirs is essentially dependent on the rainfall pattern in the dry zone of the
country. As the fingerlings should be stocked in seasonal reservoirs just after the heaviest rainy season
(November-January) in the dry zone of the country, correct timing of production of fingerlings is necessary for
successful implementation of culture based fisheries in seasonal reservoirs. Also, fingerlings are not required for
stocking in seasonal reservoirs for all the seasons, so that they can be stocked into small perennial reservoirs
(Chandrasoma, 1992).
2.1 Seed resources
For inland fisheries enhancement, major seed resources (i.e., fingerlings of Chinese and Indian major carps) are
supplied by three AQDCs functioning under NAQDA. As the technology of induced breeding has not yet been
adopted by rural farmers or private sector, AQDCs are responsible for induced breeding and rearing of post-larvae
to fry stage. AQDCs however, have limited pond space for fingerling rearing (Weerakoon, 2007). Currently,
community-based organizations (CBOs) and private pond owners (PPOs) have a significant role in fingerling
rearing for fisheries enhancement. Under the Asian Development Bank (ADB) funded ARDQIP project,
establishment of 25 mini-nurseries was envisaged for rearing fish fry up to fingerling sizes. The initial capital
investment is borne by ARDQIP on the condition that the CBOs must pay back the total amount in 60 instalments
to NAQDA (Anon., 2006b). Presently, twenty one (21) mini-nurseries are fully operational. Details of mini-nurseries
in operation as of 2005 are given by Weerakoon (2007).
2.2 Contribution of CBF to total inland fish production
Until 2004, national fish production statistics in Sri Lanka is reported in three sub-sectors namely: coastal marine
fish production, offshore/deep sea fish production and inland fish production. Since 2005, inland fish production
has been reported as (i) inland capture fisheries production; (ii) culture-based fisheries in seasonal reservoirs;
and (iii) coastal aquaculture production. Although stocking of minor perennial reservoirs commenced in 2004 as
a means of inland fisheries enhancement, CBF production from minor perennial reservoirs is not reported
separately, but included within the category of inland capture fisheries production.
In the present review, an attempt was made to deduce CBF production of minor perennial reservoirs (Table 2)
on the basis of published information on fish stocking (Anon., 2009) and average fish production (Pushpalatha
and Chandrasoma, 2010). In 2009, it was envisaged that 7.75 million fingerlings be stocked in minor perennial
reservoirs. With the average stocking density of 750 fingerlings per ha, the cumulative extent of minor perennial
reservoirs to be stocked in 2009 could be deduced as 10 330 ha. As the average CBF production in minor
perennial reservoirs is 208 kg ha
 (Pushpalatha and Chandrasoma, 2010), the total CBF production from minor
perennial reservoirs in 2009 will be in the order of above 2 000 tonnes.
Table 1.  Details on the stocking of the different types of reservoirs.
(Fingerling numbers are in millions) (Anon., 2009).
Reservoir type
Stocking details
Water bodies Fingerlings
Large reservoirs (2007/08) Not known 11.4
Minor perennial reservoirs
2007 213 4.61
2008 218 5.70
Seasonal reservoirs
2007 472 4.06
2008 321 3.00118
The annual CBF production from seasonal reservoirs in 2007-2008 was in the range of 4 600-5 100 tonnes
(Anon., 2009), forming 12.0-13.2 percent of total inland fisheries production. With the estimated total CBF
production from minor perennial reservoirs of about 1 500 tonnes (Table 2), total CBF production in the country
is about 6 600 tonnes. Accordingly, inland fisheries resources enhancement (i.e., CBF) can be considered to
account for about 17 percent of inland fisheries production in the country (Figure 2).
Table 2.  Annual CBF production of minor perennial reservoirs as deduced from the available information
2007 2008
Number of fingerlings stocked in minor perennial reservoirs (x 10
4.61 5.70
Estimated total extent of minor perennial reservoirs stocked (ha)
6 147 7 600
Estimated CBF production from minor perennial reservoirs (tonnes)
1 279 1 581
Total inland capture fisheries production (tonnes)
30 200 37 170
CBF production from minor perennial reservoirs as a percentage 4.24 4.25
of total inland capture fisheries production
Source – Anon., 2009; 
 Estimated on the basis of average stocking density of 750 fingerlings in minor perennial
 Estimated assuming average CBF production of minor perennial reservoirs as 208 kg ha
and Chandrasoma, 2010).
Figure 2.  The annual inland fisheries production from capture fisheries and
culture-based fisheries during 2007-2008
10 000
20 000
30 000
40 000
Inland capture
CBF in minor
perennial reservoirs
CBF in seasonal
Inland fish production (tonnes)
2.3 Rationale and purpose of inland fisheries enhancement
Under the “Ten Year Development Policy Framework of the Fisheries and Aquatic Resources Sector 2007-2016”
(Anon., 2007), it has been targeted that inland fisheries and aquaculture production in Sri Lanka be increased from
the figure of 36 530 mt in 2006 to 74 450 mt in 2016. To achieve this target of 104 percent increase, the following
strategies have been identified.
 Increase fish production in minor perennial reservoirs and seasonal tanks through culture based
 Increase Indian carp production through stock enhancement programs in major and medium perennial
 Increase supply of fish seed for stock enhancement by rehabilitating Government centres and
construction of mini nurseries to be operated by Community-based Organizations (CBOs);
 Strictly implement community based fisheries management in perennial reservoirs;
 Promote the efficient collection of catch statistics from perennial reservoirs;
 Promote commercial aquaculture through public/private sector participatory demonstration projects
in collaboration with SME banks;
 Promote carp culture in estate tanks; and
 Undertake aquaculture research and development in collaboration with research agencies.
The ADB funded ARDQIP project (2003-2009) has been instrumental in implementing many of the above
strategies. Under this project, physical facilities in AQDCs were improved for facilitating induced breeding of major
carps, and rearing of postlarvae, fry and fingerlings. For inland fisheries enhancement in seasonal and minor
perennial reservoirs, social mobilization and enterprise development activities were undertaken in rural areas,
through the aquaculture extension mechanism of NAQDA.
2.4 Technicalities in fisheries enhancement
As in any rural aquaculture scheme, one of the major pre-requisites for sustainability of CBF in village reservoirs
of Sri Lanka is the availability of fish fingerlings in sufficient quantities at the correct time. Realizing this regional
issue, attempts have already made to evaluate the current constraints and challenges faced by the inland fisheries
sector in the tropical region by identifying measures that would contribute to the sustainable development of
this sector (Bondad-Reantaso, 2007).
The main technology of producing seeds of major carps in the hatcheries of AQDCs is induced breeding with
the use of Ovaprim, Sufrefact, Human Chorionic Gonadotropin (HCG), Luteinizing Hormone Release Hormone
Analog (LHRH Analog) and Pituitary Glands (PG) (Weerakoon, 2007). The trained aquaculturists in the AQDCs are
responsible for the whole process in AQDCs including broodstock management, hatchery management, larval
rearing and feeding.
2.5 Operational aspects
Prior to 1990, fingerlings were issued to fisheries societies and farmers free-of-charge for fisheries enhancement
in inland reservoirs (Amarasinghe, 1995; Weerakoon, 2007). Currently, the mini-nurseries established by CBOs
purchase fish fry from AQDCs at the rate of SLRs. 0.25 per fry (In December 2009, US$1 = SLRs. 114). Selling fish
fry and fingerlings to stakeholders has been a recent development following a policy decision taken by NAQDA
after its establishment in 1998 (Weerakoon, 2007). The fingerlings are sold at the unit price of SLRs. 2.00 per
The aquaculture extension officers of NAQDA and several NGOs have been conducting awareness programs to
educate rural farmers on CBF management and development of business plans (Weerakoon, 2007). Due to the
creation of demand for fish fry and fingerlings through this process, normal market forces of demand and supply
govern the process of seed supply for enhancement strategies. Seasonality of induced breeding in AQDCs
associated with the gonad maturity cycles of broodstocks however, restricts supply of fish fry in spite of peak
In Sri Lanka, inland fisheries enhancement strategies involve CBF development in non-perennial (seasonal)
reservoirs and minor perennial reservoirs (<250 ha). In these two categories of reservoirs, two different types of
fisheries enhancement activities are practiced. The features of enhancement strategies and regulatory measures
in the two types of reservoirs are given in Table 3.120
The majority of village reservoirs which are suitable for fisheries enhancement through the development of CBF
are controlled and managed by farmer organizations, whose legal status is assured by the Department of Agrarian
Development (DAD). The minor perennial reservoirs (<250 ha) are under the jurisdiction of either the Department
of Agrarian Development or the Department of Irrigation (DI). In each village, agricultural farmers are organized
into ‘Farmers organizations’ (FO), formed under the provision of the Agrarian Development Act. The village
reservoirs are traditionally used for irrigation and various other communal activities. The other economic activities
such as CBF development in village reservoirs are therefore needed to be carried out within the constraints of
multiple uses of water resources.
Divisional Agriculture Committees (DvACs) are responsible for coordinating fisheries and agriculture activities in
villages. DvACs are presided by the Divisional Secretary (DS). DOs, local technical officers and the office bearers
of the FOs also attend these meetings, so that there is a grass-root level involvement in making decisions over
the management of village reservoirs. The Aquaculture Extension Officer (AEO) of NAQDA is also invited to attend
the monthly meetings of DvAC. There are legal provisions for various rural development activities through the
FOs, under the Agrarian Development Act No. 46 of 2000 (Anon., 2000), which include provisions for the
development of CBF in village reservoirs.
After the 13
 amendment to the Constitution in November 1987, provincial councils were established for
decentralization of administrative powers. The fisheries authorities of the provincial councils are also engaged in
inland fisheries enhancement through stocking village reservoirs. Due to inadequacies in extension mechanisms
in the fisheries authorities of provincial councils, and lack of coordination with the central government
(i.e., NAQDA), in some instances there is a conflict of interest between the provincial authorities and the central
As CBF falls within the realm of aquaculture (De Silva, 2003), defining ownership of the CBF system is
a prerequisite for sustainability. Under Section 39 of the Fisheries and Aquatic Resources Act No. 2 of 1996
(Anon., 1996a) and amended act No. 22 of 2006 (Anon., 2006c), there is a provision for licensing aquaculture
enterprises. Under these legal provisions, aquaculture management regulations were implemented in 1996
(Anon., 1996b). From the conservation point of view, there are legal provisions to protect fish and aquatic
Table 3.  The features of enhancement strategies and regulatory measures in the two types of reservoirs in
Sri Lanka
Non-perennial reservoirs Minor perennial reservoirs
Ownership and jurisdiction of Agrarian Development Department; Irrigation Department or Agrarian
water uses Farmer organizations Development Department; Farmer
Responsible community group Agricultural farmers (traditionally Agricultural farmers (traditionally
for CBF non-fishers) non-fishers) and/or fishers
Stocking density (nos/ha, yr) 2 000-2 500 217-870
Stocking size (cm)
Major carps 5-6 5-6
Nile tilapia 6-8 6-8
Stocking frequency After peak rainy season in Once a year when fingerlings are
November-January not needed for stocking seasonal
Harvesting During dry season; complete Year-round harvesting of surplus
harvesting biomass
Harvesting methods Seining; gillnetting, cast netting Gillnetting (8.5-20 cm mesh)
Management Farmer organizations (FOs) Farmer organization/fishers
Funding for CBF Revolving fund raised by the FO Revolving fund raised by the
FO/fisheries society
Sources of information: De Silva et al., 2006; Pushpalatha and Chandrasoma, 2010.121
resources from harmful fishing methods and to regulate export and import of fish under the same act. The export
and import of live fish regulations (Anon., 1998b) that specify the species of live fish that cannot be exported,
species of live fish that may be exported with a license issued by the Director, and species of live fish that cannot
be imported.
3.1 Seasonal reservoirs
In the 1980s, CBF development activities were carried out by the Inland Fisheries Division of the Ministry of
Fisheries, in seasonal reservoirs in many parts of the dry zone of the country. This strategy was essentially based
on considerable government inputs such as supplying fingerlings free-of-charge for stocking and direct
involvement of fisheries officials at all stages from stocking to harvesting. This activity came to a standstill after
discontinuation of the state patronage for inland fisheries development in Sri Lanka in 1990 in the absence of
the monitoring procedure by the centralized management unit (i.e., Inland Fisheries Division of the Ministry of
Fisheries) and lack of subsidized fingerling supply for stocking. Also as mentioned by De Silva (2003),
non-availability of effective procedures for selecting suitable reservoirs for CBF and determining appropriate
stocking densities based on biological and socio-economic criteria, lack of means of fingerling production and
over-emphasis on the biology of reservoirs, are also largely responsible for poor performance of CBF in seasonal
The ACIAR-funded project mainly focused on the development of holistic management strategies for CBF in
village reservoirs incorporating biological, physical and socio-economic factors. Accordingly, attempts were made
to develop a suitable ranking system or a scale, taking into consideration aspects such as the physico-chemical,
biological, catchment and hydrological characteristics of the water bodies, as well as socio-economic aspects
(De Silva et al., 2005). Jayasinghe  et al. (2005a, 2005b, 2006) have shown that it would be possible to classify
non-perennial reservoirs in Sri Lanka based on the limnological attributes such as Secchi disc depth, total
phosphorus, chlorophyll-a and organic turbidity as well as reservoir morphology measured as shoreline/area ratio,
in order to develop CBF. Due to natural recruitment of carnivorous fish species (such as Ophiocephalus striatus,
Mystus keletius) from associated waterways into village reservoirs which do not dry up completely, CBF harvests
of stocked species are low due to their high predation (Wijenayake  et al., 2005). It has also been found that
socio-economic characteristics favouring collective decision making for CBF development included good
leadership of officers in the society, high percentages of active members with common interest and high degree
of participation in collective work, small group size and high percentage of kinship in the group (Kularatne et al.,
All the agricultural farmers have to cooperate in CBF in village reservoirs. These agricultural farmers are
traditionally non-fishers. They have adopted CBF through adaptive learning. This participatory involvement of rural
farmers is essentially the social capital in CBF that cannot be given a monetary value.
The CBF production in 120 reservoirs from 8 administrative districts during 2007 (Dr D.E.M. Weerakoon, pers.
comm.) indicated that CBF yield varied from 14 kg/ha in Halmilla wewa in Kurunegala district to 2300 kg/ha in
Ratapera wewa in Badulla district. Stocking densities ranged from 111 fingerlings/ha in Bayawa wewa to 4 115
fingerlings in Ganegoda wewa both in Kurunegala district. Indian major carps, common carp and bighead carp
have mainly contributed to CBF harvests in seasonal reservoirs.
3.2 Minor perennial reservoirs
The demand for fish fingerlings for CBF development in seasonal reservoirs exists only after the peak rainy period
in November-January in the dry zone of the country. As such, fingerlings that are produced during the seasons
when not required for stocking seasonal reservoirs can be used for CBF development in minor perennial
reservoirs. Water management in these reservoirs comes under the jurisdiction of either Irrigation Department
(those with command area of over 80 ha) or Department of Agrarian Development (those with command area
of <80 ha).122
In 2003, Ministry of Fisheries and Aquatic Resources (MFAR) of Sri Lanka initiated through ARDQIP, a program
to introduce CBF in minor perennial reservoirs (<250 ha). In most of these reservoirs, only subsistence level
fisheries existed. There had been neither stocking nor proper management of fisheries in minor perennial
reservoirs (Pushpalatha and Chandrasoma, 2010).
Pushpalatha and Chandrasoma (2010) listed the following physical, biological and socio-economic criteria for
selection on minor perennial reservoirs for fisheries enhancement.
 Water spread at full supply level to be between 50-250 ha;
 Retention of sufficient water in the reservoirs to sustain CBF during dry seasons;
 Absence or low abundance of rooted or floating aquatic macrophytes;
 Absence or less abundance of impediments for fishing such as submerged decaying tree stumps;
 Location of reservoir in the vicinity of the village community and close proximity to markets;
 Absence of major conflicts among water users;
 Concurrence of FO with fishers for CBF development; and
 Willingness of the community to be engaged in CBF.
Under the ARDQIP project, fisheries enhancement commenced in 15 minor perennial reservoirs in 2004. In these
reservoirs CBOs were formed or re-organized and the members of CBOs were given training in basic aspects of
CBF including community-based management, leadership, simple accounting, book keeping etc. The members
of each CBO, with the assistance of aquaculture extension officers, prepared a plan for the development of CBF.
This included agreements on fish species to be stocked (based on the consumer preferences and availability of
seeds), stocking densities to be adopted, time for stocking, sources of fish seed, and CBF management measures
to be adopted.
Figure 3.  The relationship between mean SD during 2005-2006
(time t) and mean annual fish yield during 2005-2007 (time t+1)
in minor perennial reservoirs (Source of data: Pushpalatha and
Chandrasoma, 2010).
1 000
1 200
1 400
0 500 1 000 1 500 2 000
Fish Yield (kg/ha) in Year t+1
Stocking Density (Fingerlings/ha) in Year t
Y = -0.0005X
 + 0.8139X + 164.71
 = 0.1222
Species stocked were C. catla, L. rohita and
O. ni lot i cus.  I n   s ome   r e s e r  vo i r s,  C B O s
s t o c k e d   M.  ros enbe rgi i  a n d   C.  ca rpio.
According to the records maintained by
CBOs in the 15 reservoirs for 2004-2007
period (gleaned by the author), annual
stocking density (SD) ranged from 146
fingerings per ha in Mahagal wewa in
2004 to 2780 fingerlings per ha in Ranawa
in 2006. There was a positive second order
relationship (although not significant at
0.05 probability level (r = 0.35; p >0.05)),
between the mean SD during 2005-2006
to mean annual fish yield during 2005-
2 0 0 7   ( Fi g u re   3 ) ,  i n d i c a t i n g   t h a t   t h e
optimal SD for minor perennial reservoir
for fisheries enhancement is about 814
fingerlings per ha.
Unlike in seasonal reservoirs, harvesting
of fish in minor perennial reservoirs is
a year-round activity. Fishers working on
non-mechanized canoes (2 fishers per
canoe) use gillnets of stretched mesh
sizes ranging from 8.5 to 20 cm.  In all
non-perennial reservoirs where CBF were
i n t ro d u ce d,  O. ni lot i cus wa s   t h e  mo s t123
abundant species forming over 80 percent of the landings, prior to introduction of CBF. Other important species
were Channa striata, Clarias brachysoma, Anabas testudineus, Trichogaster pectoralis and Mystus keletius. According
to Pushpalatha and Chandrasoma (2010), O. niloticus continued to be the highest contributor to the harvest, even
after the introduction of CBF. In the 15 reservoirs studied, mean annual contribution of O. niloticus to the CBF
harvest was 47.4 percent (ranging from 19.7 to 66.5 percent). The overall mean contributions of three species of
exotic carps namely C. catla, L. rohita and C. carpio were 27.2, 16.9 and 4.3 percent, respectively. Pushpalatha and
Chandrasoma (2010) further indicated that in 11 reservoirs where Macrobrachium rosenbergii was also stocked,
its mean contribution to the harvest was 0.7 percent. Pushpalatha and Chandrasoma (2010) reported that percent
increase in mean annual fish production due to introduction of CBF ranged from 42.8 to 1 344 percent, with an
overall average increase of 263 percent. Prior to introduction of CBF, mean annual fish yield in the 15 reservoirs
was 57.3 kg ha
 and after introduction of CBF, it increased up to 208 kg ha
3.3 Major reservoirs
The inland fisheries production from major reservoirs (>750 ha) is essentially a capture fishery, based on the
natural recruitment of feral fish populations. The fishery is based on two exotic species, O. mossambicus and
O. niloticus, which form over 70 percent of the landings. As mentioned earlier, in recent years state-sponsored
stocking programs are being carried out in these large reservoirs.
Fisheries enhancement in seasonal reservoirs through introduction of CBF is essentially a secondary use of
small-sized village reservoirs, which have not been traditionally used for fish production (Amarasinghe and
Nguyen, 2009). CBF in village reservoirs is essentially practised by agrarian communities rather than fishers,
although this strategy is advanced by the fisheries sector institutions. As the village reservoirs (with command
area of less than 80 ha) come under the jurisdiction of Department of Agrarian Development, legal provisions
in the Agrarian Development Act No. 46 of 2000 for incorporating fisheries and aquaculture aspects in reservoir
management, facilitate fisheries enhancement.
The Kanna meeting (a community meeting held at the beginning of the cropping season) of the FOs is held at
the onset of cultivation season and is facilitated by the Agrarian Research and Production Assistant (ARPA) of the
DAD. The major purposes of this meeting include, planning of agricultural activities and making collective
decisions that cannot be changed by individuals until the end of the cultivation seasons, unless there is any
special circumstance. In addition, important decisions on CBF activities are also made. In most instances,
aquaculture management committees (AMCs) are established among FOs. For CBF activities, strategies for
stocking, guarding and harvesting are decided. The members also arrive at agreements on sharing of CBF profit
between fish farmers and agricultural farmers. Levy paid by AMC to FOs is generally about 5 percent of the profit.
FOs use this income for rehabilitation work in the reservoir. Hence, unlike in capture fisheries in major reservoirs
with co-management strategies (Amarasinghe and De Silva, 1999) where the fishers use the resource on
individual basis, in CBF group members become partners in a community-managed enterprise of which benefits
are shared on agreed basis.
Aquaculture Management Regulations of 1996 (Anon., 1996b), imposed under the Fisheries and Aquatic
Resources Act of 1996, made it possible to obtain aquaculture licenses for CBF in seasonal reservoirs. This assures
ownership of stocked fish so that poaching can be effectively prevented.
In minor perennial reservoirs, fishers have to adhere to fisheries regulations of Fisheries and Aquatic Resources
Act of 1996 (Anon., 1996a). Accordingly, fishers use only gillnets of stretched mesh sizes above 8.5 cm. The fishing
gear that are forbidden in inland capture fisheries of Sri Lanka (i.e., mono-filament gillnets, trammel nets,
surrounding nets and seine nets) are not used in minor perennial reservoirs. Pushpalatha and Chandrasoma (2010)
have reported that certain CBOs introduced larger mesh (>11.5 cm) gillnets and declared closed seasons.
From the conservation point of view, (De Silva 2003), CBF development in seasonal reservoirs is environmentally
friendly because this strategy involves use of existing waters with minimal external inputs such as artificial feeds.124
Most seasonal reservoirs do not harbour any indigenous fish, except in some reservoirs where puddles of water
remain during dry seasons supporting survival of some indigenous species such as C. striata, A. testudineus,
M. vittatus and M. keletius. Also in minor perennial reservoirs, indigenous fish species that are present are
essentially riverine species, which utilize lacustrine environments in reservoirs as feeding grounds (Amarasinghe
and Weerakoon, 2009). However, these species, according to IUCN criteria, are not considered as endangered,
threatened or vulnerable species (IUCN Sri Lanka and the Ministry of Environment and Natural Resources, 2007).
Although it has been recognized that displacement of native species is a negative impact of CBF (Gutiérrez and
Reaser, 2005), hitherto this has not been a serious issue in Sri Lanka. This is especially due to the fact that there
is clear habitat segregation between indigenous and endemic freshwater fish species, which thrive in riverine
habitats and exotic fish species that are stocked in seasonal and minor perennial reservoirs for fisheries
enhancement. Nevertheless, as most reservoirs have connections with rivers and streams, and as all exotic carp
species are known to be riverine species, impact of exotic species on freshwater biodiversity in riverine habitats
cannot be simply negated. Further studies on the impact of alien species are therefore warranted.
The enactment of the National Environment Act (NEA) in 1980, which was amended by Act No. 46 of 1980,
Act No. 58 of 1988 and Act No. 53 of 2000, included a provision for the environmental impact assessment (EIA)
process. Also under the Coastal Conservation Act, amended Fauna and Flora Protection Ordinance, Northwestern
Provincial Council Environmental Statute No. 12 of 1990 and National Heritage and Wilderness Act, there are
provisions to further strengthen regulations of the EIA process. The EIA process under the NEA however, applies
only to 31 categories of projects termed as “Prescribed Projects”, which have been specified and gazetted by the
Minister of Environment. Fisheries related projects are also included under this category. In addition to these
prescribed projects, those which fall within a declared environmentally sensitive area (e.g., wildlife sanctuary,
nature reserve), irrespective of magnitude, are required to undergo EIAs.
The Central Environmental Authority of Sri Lanka is responsible for executing NEA and delegates the
responsibilities of evaluation of environmental impact to various government agencies depending on the project.
The evaluating agency is referred to as project-approving agency (PAA). When the PAA is also the project
proponent, the CEA designates an appropriate PAA and in the event of doubt or difficulty in identifying the
appropriate PAA, CEA plays the role of PAA. For fisheries-related projects, PAA is essentially the MFAR. However,
according to Gazette notification of “Prescribed Projects” fisheries-related projects which require EIA are restricted
to, (i) Aquaculture development projects exceeding 4 ha; (ii) Construction of fisheries harbours; and (iii) Fisheries
harbour expansion projects involving an increase of 50 percent or more in fish handling capacity per annum.
In the EIA procedure in Sri Lanka (CEA, 1998, 2003), the project proponent (PP) has to submit preliminary
information to the CEA. Upon receiving this preliminary information, the appropriate PAA conducts a scoping
study and decides whether an EIA is required. If the proposed project is less damaging, an initial environmental
evaluation (IEE) is sufficient. It must be noted however, that the EIAs reported from Sri Lanka do not include
quantitative and testable predictions of impacts, which are useful for post-impact monitoring programs
(Samarakoon and Rowan, 2008). Samarakoon and Rowan (2008), who reviewed environmental practices in
Sri Lanka, have indicated that in most environmental impact statements, the ecological impact assessment was
restricted to tokenistic presentation of reconnaissance-level species lists without further analysis of the
development implications for individual organisms or communities. As such, the effectiveness of implementation
of Sri Lanka’s EIA procedure to assess the impact of fisheries enhancement on biodiversity is questionable.
However, for CBF activities in Sri Lanka, no impact assessment is carried out. Apparently, CBF is considered as an
activity that does not have significant negative environmental impacts. However, as mentioned above, there may
be negative environmental impacts on the biodiversity due to introduction of exotic species. Furthermore, as
a result of introduction of CBF in village reservoirs, rural communities have benefited.
As a means of biodiversity conservation, the live export of 13 endemic freshwater species is prohibited to be
exported in live form (Anon., 1998b). Under the same regulations, 8 endemic freshwater fish species are restricted
from export in live form which requires obtaining permits for export. They were declared as protected species125
on the basis of available scientific information on their conservation status. However, as mentioned above, the
preferred natural habitats of all these endemic species are hill-country streams (Kortmulder, 1987; Amarasinghe
et al., 2006). As such, there are no apparent adverse impacts of fisheries enhancement practiced in low-country
reservoirs, on freshwater fish biodiversity conservation.
6.1 Technical constraints
Major technical constraints to the CBF development include lack of adequate supply of fish fingerlings at the
correct time. Of the inland reservoirs numbering over 10 000, only 745 reservoirs (12.7 million fingerlings) in 2007
and 611 reservoirs (16.1 million fingerlings) in 2008 were stocked (Anon., 2009). This low percentage of reservoirs
stocked was due to inadequate supply of fingerlings and probably insufficient extension mechanisms.
6.2 Operational constraints
6.2.1 Policy level
In village reservoirs, which come under the jurisdiction of DAD fisheries and CBF development is still not a high
priority area. As CBF development is carried out by NAQDA under its mandate, DAD has less responsibility to get
involved in CBF activities. Active involvement of Agrarian Research and Development Assistants of DAD in CBF
activities would facilitate the process.
In addition, provincial councils are also involved in stock enhancement activities. The strategies that are adopted
by fisheries authorities of provincial councils are quite different from those of the central government. Generally,
establishment of CBOs is not practised by the fisheries authorities of provincial councils and as a result, CBF
activities in reservoirs where provincial councils are involved are in a poor state. Active involvement of FOs in CBF
is an essential pre-requisite for its sustainability because ownership of stocked fish is assured through this process.
Stocking of fish fingerlings as part of political agenda of the provincial councils has not been an effective means
of CBF development.
In minor perennial reservoirs, fisheries enhancement is essentially carried out by professional fishers. NAQDA’s
involvement for mobilizing the fisher communities through preparation of CBF management plans helps
significantly for its sustainability. As fishers have experienced socio-economic benefits of these enhancement
strategies, continuous demand for stocking materials prevails in many minor perennial reservoirs of the country.
6.2.2 Resource availability and cost sharing
The costs involved in CBF in seasonal reservoirs include cost of fingerlings (unit price of Rs. 2.00 per fingerling,
which has been fixed by NAQDA), cost of packing, transport, aquaculture license fee, cost of guarding stocked
fish, hiring seine nets for harvesting, and levy paid to farmer organizations of the reservoir by the aquaculture
committee. However, in 2009, as part of the state-sponsored program for food security, fingerling supply was
subsidized and commencing January 2009, fingerlings supplied free-of-charge for stocking inland waters. Levies
paid by AMC’s (generally about 5 percent of profit) to FOs are generally used for rehabilitation works in the village
6.3 Distribution of social benefits
Amarasinghe and Nguyen (2009) examined financial benefits of CBF in 23 seasonal reservoirs. The farm-gate
price per kg of fish ranged from Rs. 30 to Rs. 75. From every harvest, villagers took fish for home consumption.
Especially in reservoirs with rich harvests, aquaculture committees gave villagers fish free-of-charge. However,
this portion of the harvest was significant and ranged from 3 to 47 percent. Considering the value of the
‘home-consumption’ portion of the harvest (i.e., subsistence harvest), as determined on the basis of farm-gate126
value of fish, the net profit ranged from SLRs. 47 372 to SLRs. 729 339 (In December 2009, US$1 = SLRs 114). Of
the 23 reservoirs sampled, net profit in 17 reservoirs was above SLRs. 100 000. CBF development in seasonal
reservoirs is essentially associated with rainfall patterns in the dry zone of Sri Lanka. Accordingly, harvesting is
also necessarily bound with the dry season when the receding water levels prevail in these reservoirs. The peak
CBF production in seasonal reservoirs occurs in the August-October period because it is the harvesting period
in all seasonal reservoirs utilized for CBF. De Silva (1988, 2003) advocated staggered harvesting of CBF production
to prevent flooding of markets within a short period as well as to reduce size variation of the harvest.
Normally, the AMC in each village reservoir where CBF is practiced consists of around 10 members (Kularatne
et al., 2009). This membership is less than 10 percent of the FO. As such, the financial benefit the AMC gains from
the CBF activities results in unequal distribution of benefit. However, establishment of AMCs for CBF development
in the village reservoirs assures that those who reap the benefits bear the costs. This process is analogous to
allocation of community transferable quotas in fisheries management, where social impacts due to individual
benefits are minimized (Wingard, 2000). Introduction of a rotational system for sharing benefits among all
members of FO from year to year would further ensure benefiting all members.
6.4 Ecological impacts of enhancement strategies
As inland fisheries enhancement is essentially based on exotic species, there may be negative impacts of released
animals on the genetic biodiversity of the natural populations. However, no attempts have been made in Sri Lanka
to investigate such impacts. In Sri Lanka, inland fisheries enhancement activities are conducted in quasi-natural
water bodies. As De Silva and Funge-Smith (2005) mentioned, the impact of exotic species used in enhancement
activities on the biodiversity of indigenous flora and fauna of these artificially created water bodies cannot be
strictly considered to be serious. When the exotic species and indigenous species share food resources with great
abundance, competition between exotic and native species is unlikely (Weliange and Amarasinghe, 2003).
 Fisheries enhancement in inland waters of Sri Lanka is successful in small village reservoirs and minor
perennial reservoirs (<250 ha). De Silva and Funge-Smith (2005) have shown that stock enhancement
in large lacustrine water bodies has not been successful except in a few cases. The enhancement
strategies should therefore be restricted to small, village reservoirs and minor perennial reservoirs, at
least until the outcomes of stocking of large reservoirs is evaluated and until the constraints such as
inadequacy of fingerlings are overcome.
 Density-dependent growth and size-dependent mortality of stocked fish in CBF activities in small water
bodies are shown to influence CBF yields (Lorenzen, 2001). Further studies on this line are therefore
warranted for optimizing CBF yields in minor perennial reservoirs.
 As there is an increasing demand for fingerlings for enhancement activities, expansion of fingerling
production is necessary. In most Asian countries backyard fish hatcheries are common for the
propagation of Chinese and Indian major carps. As such, transfer of this technology would be useful
for sustaining CBF in the small reservoirs of Sri Lanka. Furthermore, establishment of backyard
hatcheries for propagation of major carps would provide rural communities with additional household
 At the full pace of CBF development in village reservoirs as envisaged in the ten year development
policy framework of the fisheries and aquatic resources sector of Sri Lanka (Anon., 2007), there will be
a possibility of surplus production flooding of the market. De Silva (1988) and De Silva and Funge-Smith
(2005) suggested that this problem can be addressed through the introduction of planned, staggered
harvesting, inter-community cooperation and improved market channels.
 Impact of stocking of exotic species on biodiversity should also be a major concern in fisheries
enhancement strategies.127
 Development of processing methods of the species commonly used for CBF is also an important
subject for further investigation. It will help preventing flooding of the market during a concentrated
harvest period. Furthermore, it may expand consumer acceptability of the product.
 CBF activity is still considered as a secondary use of reservoirs with low priority relative to irrigation.
Quantification of benefits from multiple uses of village reservoirs might therefore be useful for
convincing mid-level officials about the advantages of CBF development for improving livelihoods of
rural communities. Also, as social traditions still prevail as integral parts of rural living, this sociological
aspect should be a priority area to be considered in fisheries enhancement in village reservoirs. In some
Sri Lankan rural communities, in spite of the obvious benefits from CBF, traditional practices among
communities associated with religious beliefs, prevent CBF development.
 Lack of knowledge about the appropriate species combinations of stocked fish might result in
sub-optimal utilization of biological productivity. Development of appropriate models for optimizing
CBF yields therefore warrants further investigations.
 Development of low-cost feed from minor cyprinids using appropriate technology at affordable prices
therefore encompasses two aspects. First, this approach supports economic viability of fingerling
rearing for CBF development. Secondly, exploitation of hitherto unexploited fishery resource from
Sri Lankan reservoirs will ensure more complete utilization of biological productivity, as mentioned by
De Silva and Sirisena (1987), Amarasinghe (1990) and Pet et al. (1996).
 Community mobilization for fisheries enhancement is gradually taking a good shape in some parts of
the country. Stock enhancement practices should not however be used for the sole purpose of political
gain because such practises are bound to be unsustainable (De Silva and Funge-Smith, 2005). Further
strengthening of extension mechanisms is therefore much needed and the NGOs can play a major role
in this regard.
 As there are different administrative bodies responsible for reservoir uses other than fisheries, there is
a poor coordination of the stocking of fingerlings with water release schedules. At least in one minor
perennial reservoir (Kimbulwanaoya reservoir in Kurunegala district), with the permission from irrigation
authorities, an effective netting structure is installed by fishers near the sluice gate to prevent the loss
of stocked fish. According to fishers, this has considerably increased CBF yield in the reservoir (personal
observations). However, no quantified data are available for evaluating impact of installation of such
structures. Collection of such data is suggested to evaluate the effectiveness of such structures. As
practised in Kimbulwanaoya reservoir, fishers can bear the cost of installation.
 Generally, information on economic analyses of fisheries enhancement is poor and such information
will be useful for mobilizing communities. Recently under the ARDQIP, NAQDA has introduced
a procedure to prepare a business plan associated with CBF, although at present in a somewhat crude
form. Proper information on the economic viability of fisheries enhancement in different types of
reservoirs in different geographical regions can be used for refining such business plans.
 Although there are legal provisions for conducting impact assessment for inland fisheries enhancement,
such exercises are not carried out in Sri Lanka. Strategic environmental assessment (SEA) is also the
process for assessing, at the earliest possible stage, the environmental impacts of decisions made from
the policy level downwards. As Samarakoon and Rowan (2008) recommended, introduction of SEA is
important to strengthen institutional capacity of government institutions of the country to implement
current regulations. SEA is a promising means to strengthen awareness of biodiversity conservation
issues in the context of national priorities in terms of social and economic development.
 The ecosystem approach to fisheries and aquaculture addresses both human and ecological well-being
(Staples and Funge-Smith, 2009). As such, studies towards this direction in fisheries enhancement and
conservation strategies are useful to combine two important aspects that are of ecological and societal
interest. Here, a balance is achieved between conservation of biodiversity and ecosystem functioning,
and improvement of livelihoods and provision of food through fishery resources enhancement.128
I am thankful to Dr D.E.M. Weerakoon (former Director General of NAQDA) for providing me data CBF activities
in 120 seasonal reservoirs of Sri Lanka.129
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Tuantong Jutagate and Achara Rattanachai
Faculty of Agriculture, Ubon Ratchathani University
Warin Chamrab, Ubon Ratchathani, Thailand 34190
E-mail: tjuta@agri.ubu.ac.th and acharar@agri.ubu.ac.th
The production from inland capture fisheries in Thailand is about 1 million tonnes per annum. To sustain
this production, various types of resource enhancement and conservation practices have been implemented.
Engineering the environment and fish stocking are the two major practices adopted, and closed-season
fishing as well as control of fishing gears are used for conservation purposes. Fish stocking programs date
back to the 1950s have been continuously conducted. Fish stocking programs are totally subsidized by the
government and the stocked species include indigenous and exotic species (Chinese and Indian major carps
as well as Nile tilapia) and also giant freshwater prawn. Exotic fish are commonly stocked in village ponds
and show good returns both in terms of production and economics. On the other hand, stocked exotic fish
in large water bodies contribute a small proportion of the catches. Stocking of giant freshwater prawns
however, resulted in significant increase in economic  returns even though recapture rate was low
(<1 percent). Conservation measures are not entirely successful since violations are common unless there
is a significant investment in patrolling.
No significant impacts of stocked fish on the ecosystem were observed in terms of native fish species
richness and diversity indices. However, it is experienced that stock enhancement using hatchery
populations has led to loss of genetic variation and genetic identity of wild populations. The major
constraint, to better practices, is the institutional aspect. This is because people are not aware on the
importance of these issues with very low levels of user participation. Limited understanding of the wider
set of ecosystem processes of these stocked water bodies is also a major constraint to improved
enhancement. Options to improve both practices are discussed and new directions recommended.
Key words: Inland fisheries, Resource enhancement, Conservation, Operation, Assessment and evaluation,
1.1 Inland fisheries in Thailand
Thailand has an extensive inland water area of about 4.5 million ha consisting of about 4.1 million ha of natural
water bodies (i.e. rivers, lake and swamps) and about 0.4 million ha of reservoirs. There are 47 major rivers in seven
major river basins viz., Chao Phraya Basin, Mekong Basin, Eastern Basin, Southern Basin, Salween Basin, Mekhlong
Basin and Tenasserim Basin (Jutagate, 2009). Songkhla Lake (96 000 ha is the only freshwater/brackishwater) lake
in the south and three large natural lakes include Beung
 Borapet (13 000 ha) in the Central Region, Nong Harn
(12 500 ha) in the Northeastern Region and Kwan Payao (2 100 ha) in the Northern Region (Pawaputanon, 1992),
meanwhile about 8 000 swamps are ubiquitous country-wide (Bhukaswan, 1985). Most of the Thai reservoirs were
impounded in the second half of the 20
 century (De Silva and Funge-Smith, 2005) and in 2009, there were
25 reservoirs with a surface area larger than 1 000 ha (Vongkamolchoon, 2006), of which Pasak Jolasid is the
newest reservoir, impounded in 1998) (Thapanand et al., 2007; 2009).
“Bueng“ means the lake surrounding by wetlands.134
Thailand is recognized as having one of the most highly diverse freshwater fish fauna (573 species) in Southeast
Asia with more than 150 species identified in the catches from inland waters (Vidthayanon et al., 1997). Inland
fisheries have been long recognized and operated in the major rivers, floodplains, canals, swamps, wetlands, lakes
and reservoirs and fishing is a long standing tradition in the country (Coates, 2002). In the past there were
intensive fisheries in inland water bodies and the rivers and floodplains, where approximately 90 percent of total
freshwater production was derived from the flooded area (Bhukaswan, 1985). This has now declined, while
production from reservoir fisheries has increased significantly. Virapat et al. (2000) estimated that fish production,
from these reservoirs in 2000 as between 122 314 and 318 909 tonnes per year from the 28 956 reservoirs,
ranging in size from 0.01 ha to more than 1 000 ha.
The inland capture fisheries in Thailand was about 5 percent of the total Asian inland capture fishery (De Silva
and Funge-Smith, 2005) and the production increased over the years from about 200 000 tonnes in 1995 (Virapat
and Mattson, 2001) to about 203 000 tonnes in 2004 (DOF, 2007a). Inland fisheries provide about 3 kg/caput/yr
to the fish availability in the country, or about 38 percent of the availability from the total fish production in inland
waters (De Silva and Funge-Smith, 2005). A more recent re-estimate of production in inland fisheries based on
indicators other than catch landings indicates that inland fisheries production could be in the range of 1 016 239-
1 104 401 tonnes yr
 (Lymer et al., 2008). This indicates that fish consumption would be about 10 kg caput
and significantly higher in those areas where freshwater fish consumption is more predominant.
In general, inland fishing is often not well targeted and fishers catch all species regardless of size variation
(Bhukaswan and Chookajorn, 1988), except for certain fisheries such as traps for giant freshwater prawn fishery.
The inland fisheries are essentially artisanal and are based mainly on the indigenous species (80-90 percent),
which comprises mostly of cyprinids (e.g. carps, barbs and minnows) as well as snakeheads and catfishes (Virapat
and Mattson, 2001). The composition, distribution and abundance in fish assemblages depend mainly on
topographical condition and environmental factors of the water body. Various kinds of fishing gears are employed,
gillnets as a common gear with mesh sizes from 2.5 to 18 cm, and 4.5 to 7.0 cm being the most popular. The larger
mesh gillnets are used during the rainy season (Jutagate and Mattson, 2003). The other traditional fishing gears
include longline, cast nets, lift nets, scoop nets as well as hook and lines.
1.2 History of inland fisheries resource enhancement and conservation in Thailand
Fishing is a long standing tradition in the country and is considered an integral part of the heritage and culture,
particularly in rural areas (Coates, 2002). During the administrative reforms in 1901, the owners of the largest
fishing gear, i.e. bag-net (Pong Pang) in the floodplains were licensed for tax collection. The tariffs are used to
rehabilitate the fishing area. However, the license system was revoked to ensure a steady contribution of fish for
national consumption as well as export. This could be considered as one of the first legislative attempts for
management and conservation of inland fishery resources in the country.
In 1920, a decline of fish abundance was observed in the inland fisheries central area presumably due to heavy
exploitation. In 1921, a unit of fish propagation and conservation was established under the Ministry of
Agriculture resulting in the establishment of the “Department of Fisheries (DOF)” 1926. The DOF is responsible
for protecting and conserving fishery resources and the promotion of aquaculture in the Kingdom. Since then,
fish propagation, stocking and conservation programs have been applied in the country.
The Fisheries Law of 1947 was enacted for freshwater fisheries, which was the leading sector at that time.
Section 32 of Fisheries Law 1947 allows the Minister/Governor to issue decrees on fishery regulations. Most of
the current regulations are issued under this law. Other relevant sections are Sections 6 and 7. According to
Section 6, fishing grounds are divided into four types: sanctuary, auction, permission, and public areas while
Section 7 grants authority to provincial committees to announce specific fishing measures in their provinces as
per approval of the Minister (Sihapitukgiat et al., 2002).
The official freshwater fish stocking program, for maintaining and increasing fisheries productivity in Thailand can
be dated back to the 1950s, when the program was conducted in Bhumibhol and Ubolratana reservoirs and some135
of the large lakes such as Kwan Payao and Beung Borapet by the Department of Fisheries (Virapat, 1993). This
program had been intensified by regular stocking in large water bodies under “The Nation-wide Fish Stocking
Program”, in which more than 700 million fish and shellfish were stocked in about 5.6 million ha of water bodies
(Bhukaswan, 1989).
2.1 Engineering the environment
The common practices are removal of aquatic weeds, clearing of accumulated bottom sediments and maintaining
optimum water levels. Presently, to implement both activities, DOF manages the large swamps and lakes while
the other water bodies are managed by various authorities i.e. the river and irrigation reservoirs by the Royal
Irrigation Department (RID), hydropower reservoirs by the Electric Generating Authority of Thailand (EGAT) and
village ponds by the sub-district administration organization in each area. Sediments and weed removal are done
regularly in large water bodies and extensively for village ponds. In 2009, DOF had conducted sediment removal
in the important large three lakes (see 1.1), totaling 2 450 000 m3
 and weed removal of 200 000 tonnes
(DOF, 2008). Meanwhile maintenance of optimum water levels are mainly through construction of the gates in
the outlet area such as the cases of Beung Borapet where the water level is maintained at +23.8 m above MSL
(Srinoparatwatana, 2009) or 157.5 m above MSL for Nong Harn (Srichareondham and Ko-anantakul, 1993), with
the purpose of extending the flooding area and duration of the flooded area in order to extend the production
area and period.
Other examples of engineering the environment in Thailand can be listed as:
 Construction of artificial habitats or “Baan Pla” (or “fish house”): this activity is done by providing
substrates for natural colonization by food organisms, which act as a refuge as well as feeding grounds
(Welcomme and Bartley, 1998).
 Construction of fish passages: this construction aims to enhance the fish production, especially in the
upstream area, through the construction of weirs or dam across river channel, particularly in the major
rivers (Suntornratana, 2003). However, the effectiveness of the fish passage is still questioned since with
many species of fish there is usually not a good fit with designs for a single type fish passage (Jutagate
et al., 2005)
 Fertilization: Introducing nutrients, into the ecosystem in order to boost primary productivity, to
increase fish production. This activity has been widely applied particularly in village ponds with high
stocking densities, in which chicken manure is usually used as the source of nutrients (ADB, 2005).
2.2 Fish stocking programs
The most recognized fisheries resource enhancement in inland water bodies in Thailand is the fish stocking
program. Fish stocking is regularly employed in large water bodies for the general benefit of the open-access
fishers who continue to rely on these resources (De Silva and Funge-Smith, 2005). Generally it is suggested that
there are four categories of fish stocking in the country (Cowx, 1998; Welcomme and Bartley, 1998).
 Creation of new fisheries: A good example of this strategy is the stocking of giant freshwater prawn,
Macrobrachium rosenbergii into reservoirs, large inland water bodies and rivers. This activity has been
conducted over a fairly long period of time; however, reliable data on stocking are available only since
1998 (De Silva and Funge-Smith, 2005). The stocking of this species is relatively uncommon and it has
to be restocked regularly since it requires brackish water in its early development stages, which is
usually not available in the natural or man-made lakes in the country, except Songkhla Lake.
M. rosenbergii has been regularly stocked in lacustrine water bodies since 1990. From 1998-2003, fifteen
Thai rivers were stocked in one or more years, with nearly 70 million post-larvae.136
 Compensation/mitigation: stocking for the purpose to mitigate serious disturbances of aquatic
environment caused by human activities has been conducted as in the case of fish stocking in Pong
and Chi Rivers (Northeastern region) after the polluted condition in both rivers in 1992 caused by the
sewages from the “Pulp & Paper” company (Inland Fisheries Resources Group, 1993) and the case of
Chao Phraya River in 2007 caused by the sinking of the “sugar” containers (PCD, 2007)
 Conservation: stocking to retain the endangered and threatened species is also a common practice led
by DOF such as stocking of the threatened Chao Phraya giant catfish  Pangasius sanitwongsei
(Juntasutra et al., 1989; Hogan et al., 2008) and the Mekong giant catfish, Pangasianodon gigas (Polprasit
and Tevaratmaneekul, 1997; Sriphairoj et al., 2007). Moreover, on special occasions such as on the
birthday of the royal family members or religious ceremonies, there are also programs to stock Thai
indigenous fishes into rivers country-wide, through a project under the patronage of Her Majesty the
Queen (Sinchaipanich and Sookthis, 2001).
 Enhancement: From 1950s to 1970s, the common stocked species were Chinese carps viz., grass carp,
Ctenopharyngodon idella, mud carp,  Cirrhinus molitorella, silver carp, Hypophthalmichthys molitrix,
common carp, Cyprinus carpio and bighead carp, Aristichthys nobilis, Indian major carps viz., mrigal,
Cirrhinus mrigala and rohu, Labeo rohita (Pawaputanon, 1988), tilapia, Oreochromis niloticus and giant
freshwater prawn M. rosenbergii (Bhukaswan, 1989). However, only a few species were reported as
successfully established such as rohu, tilapia and giant freshwater prawn (Pawaputanon 1986;
Pawaputanon 1987; Virapat, 1993). According to De Silva (2003), stocking of these fishes, except for
tilapia, is closer to culture-based fisheries rather fish stocking. Although these species are capable of
reproducing, they cannot form sufficiently large populations that could be exploited commercially
unless re-stocking is practiced.
Since 1980, the stocking of indigenous species was initiated as one of the DOF policies on fisheries conservation
in natural waters in Thailand (Anonymous, 1988). One of the major reasons is the attempt that these species could
self-recruit, which could be harvested regularly without regular stocking (Little, 2002). The popular species for
stocking are silver barb  Barbonymus gonionotus, seven-line barb  Probarbus jullieni, broad-head walking catfish
Clarias macrocephalus, common Siamese barb Henicorhynchus siamensis, iridescent shark catfish. P. hypophthalmus,
tinfoil barb  Barbodes schwanenfeldi, golden barb  Barbonymus altus, black eye shark catfish  Pangasius larnaudii
and tiny scale barb Thynnichthys thynnoides. In 2009, the total numbers of stocked fish and giant freshwater prawn
into inland water bodies country-wide was estimated at 2 500 million (Table 1) and the genetically improved
strains (Table 2). Meanwhile 1 950 million fish were stocked in 2008 (DOF, 2008).
Table 1.  Targeted numbers (× 10
) of stocked fish for inland fish stocking program in Thailand for the fiscal year
2009 (October 2008 – September 2009) country-wide (DOF, 2008)
Species Total Species Total
Shellfish Fish
Macrobrachium rosenbergii 350 000 Barbonymus schwanenfeldii 18 850
Fish Pangasius hypopthalmus 12 631
Barbonymus gonionotus 382 250 Clarias macrocephalus 8 300
Labeo rohita* 224 350 O. niloticus (GIFT) 6 500
Cirrhinus mrigala* 104 670 Morulius chrysophekadion 6 200
Cyprinus carpio* 78 100 Systomus orphoides 5 200
Oreochromis niloticus 72 700 Hypophthalmichtys molitrix* 4 050
Leptobarbus hoevenii 40 720 Ctenopharyngodon idellus* 2 850
Barbordes schwanderfii 39 780 Trichogaster pectoralis 2 500
Henicorhynchus siamensis 26 120 Miscellaneous** 14 229
Note: * exotic species
** Miscellaneous includes Clarias macrocephalus, Hemibagrus wyckiodes, H. nemurus, Pangasius conchophilus, Probarbus
jullieni and other indigenous species for conservation purpose.137
3.1 Closed fishing season
The legal basis for the statutory closed fishing season and closed areas is to protect the broodstock from the
impacts of fisheries during the breeding season. Although the fish composition is very diverse in the country, the
dominant group is the cyprinids, most of which spawn during the early part of the rainy season (De Silva, 1983).
Therefore, the closed season in inland waters is set during this period and last for four months, i.e. from 16 May
to 15 September country-wide except in some specific areas, where seasons are more closely related to the onset
of rainy season in each area (Table 3). However, fishing for household consumption is permitted.
Table 2.  Targeted numbers (× 10
) of genetically improved strain fish for inland fish stocking
program in Thailand for the fiscal year 2009 (October 2008 – September 2009) in country-wide*
(DOF, 2008)
Species Total Species Total
Giant Freshwater prawn 14 000 Common carp 4 600
Fish Tilapia (Chitralada strain) 4 000
Silver barb 16 800 Red tilapia 1 200
Rohu 8 100 Miscellaneous** 1 300
Note: * All strains are genetically improved by National Aquaculture Genetic Institute, DOF
** Miscellaneous includes pangasiid and clariid catfishes
Table 3.  Closed fishing seasons for the inland fisheries of Thailand
Province (Region) Closed fishing season
Lamphun (North) 1 June – 30 September
Lampang (North) 1 May – 31 August
Khon Kaen, Udon Thani and
16 June – 15 October
Nong Bualampoo (Northeast)
Nakhon Nayok (Central) 13 April – 12 August
Phatthalung (South) 1 October - 31 January
Pang Nga (South) 1 May – 31 August
Narathiwat (South) 1 September – 31 December
3.2 Fish conservation zones (or Closed areas)
This measure aims to prevent fishing pressure on the broodstocks and recruits, especially during the spawning
season. Moreover, a secondary benefit of this measure is through the conservation of biodiversity. Thus,
declaration of the fish conservation zone in each inland water body is based on scientific evidence on spawningand nursery-grounds, which could be temporary during spawning season, e.g. Pasak Jolasid (Vongkamolchoon,
2006), or permanent, e.g. Beung Borapet (Srinoparatwatana, 2009). Moreover, there are cases where fish
conservation zones are established at the village level and are often associated with animist beliefs and often
fish in the temple areas are consciously protected for religious reasons (Baird, 2006).
3.3 Control of fishing gears
The Fishery Act of 1947 prohibits destructive fishing practices such as poisoning, electro-fishing, and the use of
explosives. The fishing gears, that often inflict serious damage to fish stocks, such as trawl, purse seine and push
net, are also banned. Mesh size regulations are difficult to apply to select a certain size of one species in these138
very multi-species fisheries, which target a diversity of fish sizes (Pawaputanon, 2007). In general, the minimum
mesh size designed for inland fisheries is set at 5 cm (stretched mesh), which allows the juveniles and sub-adults
of many species to escape from the gear (Jutagate and Mattson, 2003).
4.1 Authorized organizations
The Department of Fisheries (DOF) is the main organization responsible for aquatic resources enhancement and
conservation as indicated in the National Environmental Quality Act B.B. 2535 (i.e. 1992). According to DOF, inland
stock enhancements are implemented by the Inland Fisheries Research and Development Bureau (IFRDB) wherein,
seed supplies are propagated in its 27 inland fishery stations and 31 inland fisheries research and development
centers. These seed are stocked in the large and small water bodies. Apart from providing seed, DOF also
(i) support the rehabilitation or construction of village ponds; (ii) train local support personnel; and (iii) provide
technical advisory services (Chantarawarathit, 1989). Moreover, DOF also established 162 fish breeding centers
(FBCs) based in local communities to supply seeds to stock in small water bodies but only 39 FBCs are currently
in operation, with a seed production capability of about 6.8 million fingerlings (ADB, 2005).
The Bureau of Fisheries Administration and Management (BFAM) is responsible for freshwater fish conservation
purposes. There are 18 units and seven centers for inland fishery patrol, surveillance and control of the fisheries,
especially in the spawning and nursing grounds during the closed season, covering 43 rivers (112 115.8 ha),
13 natural lakes (84 995 ha) and 65 reservoirs (356 973 ha) country-wide (BFAM, 2009). Moreover, as mentioned
in 2.1, the main purpose of reservoir construction in Thailand is for either hydropower or irrigation. EGAT and RID
are the authorized organizations in charge of maintenance and rehabilitation of the ecosystems of man-made
lakes under their control.
The 1997 Kingdom’s Constitution contains provisions for administrative devolution, so that people, or groups of
people (e.g. Provincial Administrative Organizations (PAOs): see 1.2), can take part in the management of their own
natural resources, including fish resources. They may participate in drafting sets of rules to manage their fish
resources and fisheries. These include the periodic stocking in the water bodies within the provinces, demarcation
of fishing grounds, prohibition of some fishing gears, and introduction of fishing seasons and fishing fees
(Sihapitukgiat  et al., 2002). In terms of village ponds and reservoirs, these practices are controlled by the
Sub-district Administrative Organizations (SAOs) (DOF, 2007b).
4.2 Funding mechanisms
Majority of the budget for inland fish stock enhancement and conservations is allocated by the government
through DOF. In the 2009, 815.8 million Thai Baht was allocated for stock enhancements of both for inland and
marine fisheries and 281.2 million Thai Baht for implementing conservation practices. Moreover, the Ministry of
Interior, through Department of Local Administration, annually allocates a budget to the PAOs and SAOs for their
natural resources management and the budget for village pond construction has been progressively transferred
to SAOs since 2000 (ADB, 2005).
4.3 Management/enforcement/participation
4.3.1 Engineering the environment
Removal of aquatic weeds and clearing of accumulated bottom sediments are done regularly in the three large
lakes by DOF (DOF, 2008) while for large reservoirs this is done by EGAT and RID. These activities are the done
regularly in the rivers by RID and irregularly by the PAOs and SAOs with the people’s participation, particularly
for purposes of flood defense, irrigation and navigation. SAOs also have responsibility for the rehabilitation of the
village ponds in their communities.139
4.3.2 Fish stocking in small water bodies
This stocking refers to the fish stocking into the village ponds and reservoirs, which are built and maintained
primarily to store water for domestic use and irrigation (Lorenzen et al., 1998); with an average size of 8 ha and
depth at 2.5 m and 1.5 m in wet and dry seasons, respectively (Suraswadi, 1987) and water storage could be at
least 8 months in a year (Terdvongvorakul, 2002). The common stocked species are forage species such as tilapia,
Indian major and Chinese carps, except common carp C. carpio, as well as silver barb; where the seed supplies
are partly subsidized by DOF and purchase from private traders (Chantarawarathit, 1989; Lorenzen et al., 1998).
The stocked fish are generally 2-3 cm with the recommended stocking density at 50 000 fish ha
 (DOF, 2007b)
but commonly at 10 000 fish ha
 (Lorenzen et al., 1998). Fish are stocked during the wet season and raised for
6 to 8 months (DOF, 2007b).
Fish stocking in village ponds are controlled by the SAO, through the village fishery committee, which assumes
responsibility for pond management and also trained on relevant management techniques (Lorenzen et al., 1998).
Pond management is also conducted both before stocking (e.g. controlling of bank erosion, elimination of
predators, liming and fertilization) and during rearing (e.g. feeding with rice bran or artificial pellets, fertilization
and surveillance against poaching). Terdvongvorakul (2004) reported that about 60 to 70 percent of village ponds
were limed/fertilized before stocking.
Three types of harvesting methods in the village pond (DOF, 2007b):
 Harvesting once a year: This type can be applied by setting an annual fishing day, once the fish grow
to market size (about 6-8 months after stocking). Tickets are sold to both individuals within and outside
the village for catching fish (Lorenzen et al., 1998) and the income is for the village fund. Ticket prices
depend on the types of fishing gear used, numbers of stocked fish, numbers of fish expected to survive
and condition of the pond (Chantarawarathit, 1989). There are also cases in which the pond is rented
out to private groups to operate stocking and the production is either harvested by the lessee or
through the sale of tickets. However, although the pond is leased, the villagers still have a right to access
the pond for agricultural water supply and household uses (Chantarawarathit, 1989). About 25 percent
of village ponds in northeast of Thailand are harvested under this regime (Terdvongvorakul, 2002).
 Staggered harvesting: In the perennial pond, the fish could be harvested periodically and with regular
re-stocking to sustain the production in the pond. Stocking of self-recruiting-species (SRS) is also
recommended, especially tilapia. This is a very common harvesting practice, which takes place in about
70 percent of village ponds operated under this regime (Terdvongvorakul, 2002).
 Combined type: If the water body is large enough, zoning is recommended. The water body could be
divided into an open zone (fishing for daily consumption) and the reserved zone (fishing at an annual
fishing day), which can provide income to the village. Regular re-stocking and intensive pond
management are recommended.
4.3.3 Fish stocking in large water body
The main stocked species comprise of exotic and indigenous species as well as the giant freshwater prawn. The
genetically improved strain which show higher growth rate such as “GIFT” strain of O. niloticus (GIFT-genetically
improved farmed tilapia) and genetically improved silver barb  B. gonionotus are also stocked (Pongtana and
Autlerd, 2005). The stocking densities generally follow the protocol set by the DOF advisory team (IFRDB, 2009)
as follows:
 From 125 to 300 fish ha
 in the lakes (natural and man-made) that are larger than 16 000 ha
 About 625 fish ha
 in the lakes (natural and man-made) that are smaller than 16 000 ha
 More than 625 fish ha-
 in rivers, and
 About 625 fish ha
 in small to medium lakes (natural and man-made) that range between 10 and
160 ha.140
The seed fish range from 3-5 cm and are nursed in hapas for 45 days to sizes between 5 and 7 cm before
releasing. Equal proportions (in numbers) of each stocked species are recommended in the small to medium lakes.
Giant freshwater prawn released as post larvae (PL) 30 days, i.e. stage PL30 (Sripatrprasite and Lin, 2003a).
Fish stocking is generally conducted during the rainy season (i.e. May to August) to guarantee the abundance
of natural food (i.e. phytoplankton) and shelter for the stocked seed, especially in the flooded forest. On the
stocking day, DOF staff also promotes through media people to get involved in the activity on a voluntary basis
with the objective to let them be aware of the importance of aquatic animals (Sinchaipanich and Sookthis, 2001).
Massive numbers of fingerlings are also stocked during Songkran festival (i.e. a Thai traditional New Year), which
starts on April 13 and lasts for 3 days. April 13 is declared as the national fisheries day, in which fish stocking is
one of the main activities of the day.
4.3.4 Conservation practices
Surveillance and monitoring on the use of the destructive fishing methods are continuously conducted by the
inland fishery patrol units. During the closed fishing season, the units pay particular attention to spawning and
nursery grounds. There are staff in charge of giving infringement warnings and prosecutions of those fishers who
violate the regulations (BFAM, 2009). Community education and extension to disseminate the fishery information,
encourage the people to be more aware of the importance of aquatic animals and a responsible fishery, are also
the duties of these units (Sinchaipanich and Sookthis, 2001). Community-based management has also been
initiated, especially in large lakes and reservoirs, with the purpose of sharing the responsibility and authority
between the government and communities in a decentralized approach to increase compliance to these
5.1 Engineering the environment
The surface area of large lakes is generally increased by about 20 percent after rehabilitation (Inland Fisheries
Division, 1997a). Significant increases of the fish standing crops after rehabilitation was observed such as from
22 kg ha
 to 61 kg ha
 in Nong Harn (Duangswasdi et al., 1994), from 6 kg ha
 to 26 kg ha
 in Beung Borapet
(Rithcharung and Pongchawee, 1995) and from 3 kg ha
 to 11 kg ha
 in Kwan Payao (Inland Fisheries Division,
1997). Similar results also are retrieved from the medium-sized reservoirs, where the fish standing crops changed
from 29 kg ha
 to 60 kg ha
 (Chunchom and Taruwan, 2006). There is also evidence that after rehabilitation, the
ratio between forage and carnivorous fish (F/C ratio) shifted to a more optimum range, from 3 to 6, in many lakes
(Inland Fisheries Division, 1997).
Effectiveness of fish passages had been also evaluated and their performances generally noted to be poor. Only
the sub-adults and small-sized species can utilize the passages, which as a consequence provides limited
enhancement of the yields in the headwaters compared to when there was no barrier (Jutagate et al., 2005).
Sripatrprasite and Lin (2003b) estimated that about 10 percent of the fish caught in the Pak Mun Reservoir were
from the fish that ascended the fish ladder. There is no study, so far, to determine the effectiveness of artificial
habitats in terms of yield enhancement. However, Welcomme and Bartley (1998) suspected that this kind of
construction is mainly a fish aggregating device with no increase in overall productivity.
5.2 Fish stocking in small water body
The average yield from stocking program in village pond is around 290 kg ha
 for poorly managed village
ponds (Terdvongvorakul, 2002) and could be as high as 3 000 kg ha
 (Lorenzen et al., 1998). It is estimated
that the average high yield at 375 kg ha
 could be achieved at a stocking rate of 37 500 fish ha
and yield
trend to decrease when stocking beyond this rate (Figure 1: Inland Fisheries Division, 1997b). De Silva and
Funge-Smith (2005) suggested that increasing fish numbers through stocking will not be effective and there is
the possibility for it to be counter-productive by diminishing growth. The common stocking species revealed141
2 000
4 000
6 000
8 000
10 000
12 000
14 000
Stocking density (number rai
Production (kg rai
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
SD (1 000 ha
TP ( mg l
Yield (kg ha
3 000
2 500
2 000
1 500
1 000
Note:   Rai is a Thai measurement scale, in which 6.25 rai
equals 1 ha
Figure 1. Relationship between productions (kg rai
and stocking density (numbers rai
) (Inland Fisheries
Division, 1997b)
Figure 2.  Predicted yield as a function of total
phosphorus (TP) and stocking density (SD) in village
ponds in NE of Thailand (Lorenzen et al., 1998)
Production (kg rai
Village pond size (rai)
0 10 20 30 40 50 60 70 80 90 100 110 120
Note:  Rai is a Thai measurement scale, in which 6.25 rai
equals 1 ha
Figure 3.  The positive skewed distribution of the
p r o d u c  t i o n   i n   re  l a t i o n   to   v i l l a g e   p  o n d s   ( I n l a n d
Fisheries Division, 1997b).
good growth performance, where they can grow
beyond 30 cm i.e. considered as marketable size,
wi t h i n   o n e   ye a r   i n   a   sma l l   i r r i g a te d   re s e r  vo i r
(Saowakoon, 2009). Meanwhile, the fish could grow
slower in village ponds, i.e. less than 1 kg within
a year (Lorenzen et al., 1998).
The recapture rates of stocked fish fluctuated and
ranged from 14.5 to 100 percent of total catch with
the average of 51 percent in small swamps and lakes
(NIFI, 1984; NIFI, 1988) and could be as high as
60 percent in village ponds (Lorenzen et al., 1998). In
village ponds, stocking performance is influenced by
stocking density and trophic status of the water
body (Figure 2: Lorenzen  et al., 1998), meanwhile
Terdvongvorakul (2004) had added water level and
drying period of pond as controlling factors on fish
production. Size of village pond is considered as
another factor that has negative relationship to fish
yield. Fish yield decreased from about 310 to 94 kg
 in ponds sized 62.5 and 750 ha, respectively
(Inland Fisheries Division, 1997b) and the production
in relation to village ponds tended to be positively
skewed (Figure 3: Inland Fisheries Division, 1997b;
Terdvongvorakul, 2002).
5.3 Fish stocking in large water body
Fish stocking may be claimed to be the most successful enhancement activity particularly in large lacustrine water
bodies (Bhukaswan, 1980). However, the contribution of exotic stocked species (i.e. Chinese and Indian major
carps) to the total yield is very limited, except for tilapia, which has the ability to self-recruit in the system. The
indigenous species, on the other hand, have proven to be successful based on the high yields of snake-skin142
gourami T. pectoralis (Bhukaswan, 1980) and Smith barb  P. proctozystron in Ubolratana Reservoir (Petr, 1989)
since they had been stocked in 1969 and 1977, respectively. Silver barb B. gonionotus has also been recognized
as a successful stocked species for improvement of fish yields in many Thai reservoirs (Pawaputanon, 1992).
Nevertheless, not all indigenous stocked species have performed well in enhancement. For instance, the poor
contribution of some indigenous stocked species such as Mekong giant catfish P. gigas, Chao Phraya giant catfish
P. sanitwongsei, iridescent shark P. sutchi, Isok barb P. julieni and Giant barb C. siamensis, especially in lakes (Virapat,
1993). Stocking of species which are endangered, for conservation purposes to improve the status of wild stocks
(Mattson et al., 2002) and of migratory species that need to migrate to a riverine habitat for breeding (De Silva
and Funge-Smith, 2005) are also noted.
Benchakarn and Nookour (1988) studied the survival rate of rohu  L. rohita fingerlings of sizes ranging from
3.15 to 13 cm in polyethylene net pens before stocking and found that the overall survival rate was 18 percent
after 49 days of stocking. In general, the survival rate of the stocked Indian major carps was estimated at about
10 percent and less for Chinese carps, which could be due to the fact that the fingerlings of Chinese carps are
slow swimming fish and thus are more susceptible to predation than the fast swimming Indian major carp
fingerlings (Virapat, 1993). Moreover, the seed fish are typically removed rapidly from the ecosystem by fishing
since the commonly used gillnets are both small to large mesh sizes, which are effective in catching matured
natural species of relative small-size and young age-classes of stocked species (Virapat, 1993).
Pawaputanon (1988) studied the most effective released size of three stocked species viz., bighead carp, mrigal
and rohu at three different size classes, large (9-10 cm), medium (7-8 cm) and small (3-5 cm). The recaptured rates
were about 10.2 and less than 1 percent for the large, medium- and small-sized fingerling, respectively. The
appropriate stocked size, therefore, was recommended at 9-10 cm. This result was reconfirmed by a number of
reports (e.g. Siripun, 1988; Virapat, 1993) that the 9 cm size-class for Indian major carps is recommended when
considered in terms of survival rate, yield and economic viability. Nonetheless, the stocked size is generally at
5-7 cm since the limited budget of DOF to rear the stocked fingerlings to attain the recommended size (see 4.3.3)
and if the fish are stocked at appropriate size, they could attain the marketable size within eight months to an
year (Pawaputanon, 1988), Unfortunately, there is no report that provides statistical information and performance
of stocked Thai indigenous species.
For the giant freshwater prawn, the average weight of individuals after a year of release (at stage PL30) ranged
from 110 to 167 g with the average relative growth rate at 20.7 g mth
 and could grow up to about 400 g
(Sripatrprasite and Lin, 2003a; Renunual and Silapachai, 2005). The recapture rate of the giant freshwater prawn
is very low ranging from 0.83 percent in run-of-the river type reservoir (Jaiyen, 2005) to about 2 percent in the
lake-type reservoir (Benjakarn, 1984; Renunual and Silapachai, 2005). However, the recapture rate of the stocked
giant freshwater prawn in natural lakes such as Beung Borapet could as high as 10 percent (Rithcharung and
Srichareondham, 1998). There is no study about the optimum stocking size and density but the stocked rate of
freshwater prawn is at about 2 500 prawn ha
 (Jaiyen, 2005). There is no study yet on the relationship between
the stocking quantity and yield but in Pak Mun Reservoir, stocking of 2 million juveniles resulted in the production
of 3 kg ha
 (Sripatrprasite and Lin, 2003a) and by stocking 40 million juveniles in 2003, the production was
as high as 11.5 kg ha
 (Jaiyen, 2005).
5.4 Conservation practices
It can be said that, in general, the conservation practices implemented by DOF in inland waterbodies are not
entirely successful. The strict regulations to prohibit fishing during the rainy season have been shown to be
ineffective since the highest yield of inland fisheries is during this period (Benchakarn, 1986). During this period,
all freshwater fisheries resources are very productive and yearling fish grow to full size and are the target of fishers
(Pawaputanon, 2003). Fishers have adopted practices to minimize the chance of being arrested by fishery patrol
such as setting their fishing gears in the zone that the fishery patrols infrequently survey during the closed
seasons (Srinoparatwatana, 2009).
One would expect a higher species richness and biomass in fish conservation zones (FCZ). However, a recent
study by Srinoparatwatana (2009), at Beung Borapet revealed inconsistent patterns among fish species143
between the fished zone and FCZ. Some dominant species such as barb  Cyclocheilichthys enoplos, barb
Amblyrhynchichthys truncatus, giant gourami O. gouramy and Smith barb P. proctozystron had higher densities in
the FCZ, whereas the other dominant species such as catropa Pristolepis fasciatus, Nile tilapia O. niloticus, Beardless
barb  Cyclocheilichthys apogon and glass fish P. siamensis had higher densities in the fishing zone. Moreover,
protection only appeared to increase the size of a few dominant species e.g. O. gouramy and Silver barb
B. gonionotus. Nevertheless, strict control of fishing activities by fishery patrol within the spawning and nursery
grounds particularly during spawning periods has been successful in terms of reducing mortality of broodstock
and increasing recruitment in many lakes and rivers that are patrolled effectively (JICA, 2001; Vongkamolchoon,
2006; Chansri et al., 2008).
Since the nature of inland fisheries in Thailand is often not targeted and the fishers take all species regardless
of size variations (Bhukaswan and Chookajorn, 1988), it is difficult to make an effective control by designing
a single mesh size especially for the commonly used fishing gear such as gillnet (Jutagate and Mattson, 2003).
Presently, the minimum mesh size restriction is 5 cm as announced by the DOF but the lesser mesh sizes are
always commonly deployed. Chansri et al. (2008) reported that even though the percentage of the perception
of fishers on the conservation practices, implemented by DOF, was high (57 percent), the rate of compliance was
very low because they have no alternative source of income, especially during the closed season.
6.1 Impact of stocked fish on ecosystem
Koranantakul (1973) reported on the impact of common carp C. carpio on the disturbance of the ecosystem in
village ponds by stirring up sediment leading to increased water turbidity due to re-suspension of sediment
granules and a higher level of particulate inorganic matter, resulting in a decrease of the pond’s primary
productivity. This is the reason why this species is not popular for stocking in such systems (see 4.3.2). Other
impacts of stocked species had been mentioned but there has not yet been any in-depth studies on topics such
as (a) decline in local fish species because their eggs are eaten by C. carpio and Nile tilapia O. niloticus or (b) loss
of native habitat, especially in the vegetation areas due to the foraging of excess stocked grass carp C. idella
(Welcomme and Vidthayanond, 2000).
Arthur et al. (2010) conducted experiments in wetlands in southern Lao, which has the similar zoogeographical
condition as the northeast of Thailand and found that the native fish biomass was not affected by stocking of
the non-native species. No significant impacts on native fish species richness, diversity indices, species
composition or feeding guild composition were detected. De Silva and Funge-Smith (2005) mentioned that the
primary reason that most stocked species (particularly the Chinese and Indian major carps) do not tend to
influence the biodiversity of large inland, lacustrine water bodies is that they are generally unable to reproduce
in such waters and form large populations that would compete for common resources. Among the exotic stocked
species, only Nile tilapia reveal the potential to self recruit after release (Virapat, 1993) meanwhile the other
stocked exotic species seem to acclimatize gradually due to lack of spawning sites and habitat of parental sites
(Villanueva et al., 2008). In terms of niche overlap, Nile tilapia has a large niche breadth, i.e. high ability to consume
a variety of diet types (Nithirojpakdee et al., 2006). Meanwhile the other exotic carps have small niche breadth
and compete for food sources with indigenous fishes (Villanueva  et al., 2008). However, low gross efficiency
transfer of primary production through the catches (i.e. range from 0.1 to 0.2), are commonly found in Thai inland
waters (Jutagate et al., 2002; Villanueva et al., 2008; Thapanand et al., 2009) suggesting that there is a large excess
production of phytoplankton and plants and implying that these food sources are not strongly affected by
competition within the fish groups.
6.2 Impact of stocked species on the genetic biodiversity of the natural population
Releasing of indigenous species can lead to genetic effects if interbreeding between released fish and wild fish
occur. Generally, released fish are hatchery bred. Interbreeding of these fish with wild population will result in
alteration of the genetic structure of the wild populations and reduction in genetic diversity, if the hatchery144
population released has lower genetic diversity than the wild populations. Genetic variation in hatchery
populations can be lost by domestication, inbreeding and selective breeding. Moreover, the released hatchery
population may not originate from local populations, which is greatly different in the genetic make up from wild
populations, resulting in genetic homogenization among populations and loss of genetic identity. Finally, this
effect can reduce local adaptation and viability of wild populations. To date, there are only limited numbers of
genetic studies regarding the impacts of releasing indigenous species in Thailand. Kamonrat (1996) studied the
genetic structure of Thai silver barb, B. gonionotus natural populations and hatchery stocks from three river basins
(including Chao Phraya, Mekong) and reported that over 70 percent of river populations were from hatchery
populations, possibly resulting from restocking. Similarly, a study on B. gonionotus and H. siamensis populations
from the lower Mun River before and after stocking indicated that stock enhancement using hatchery population
has led to loss of genetic variation and genetic identity of wild population (Kamonrat, 2008).
In Thailand, Senanan et al. (2004) and Na-Nakhorn  et al. (2004) observed the introgression of African catfish,
C. gariepinus gene into native catfish, C. macrocephalus in wild populations caused by the release/escape of hybrid
catfish (C. macrocephalus x, C. gariepinus). Na-Nakorn et al. (2004) observed that C. macrocephalus in the wild may
be directly replaced by the hybrid catfish that have higher growth rate and suggested that a better strain of
C. macrocephalus should be developed to avoid spreading of hybrid catfish in the wild. Moreover hybrid catfish
has been thought to be a species contributing to the decline of native  C. batrachus in the Mekong Delta
(Welcomme and Vidthayanon, 2003).
6.3 Socio-economic benefit
Recently, DOF has launched a project (started in 2007) to assess the catch per unit effort (CPUE) by using standard
gillnets, in a number of large water bodies to assess the success of enhancement programs and mitigation
measures by setting the goal at 1 percent higher in CPUE compared to the previous year (IFRDB, 2007). It is
anticipated that this rate of increase will provide more benefits to the people in the area, particularly in terms
of food security. Chantarawarathit (1993) and Pimolbutra (1994) reported that more than 80 percent of the people
living in the vicinity of large natural lakes were satisfied with the condition of the lakes after rehabilitation but
numbers of fishers claimed that their catches had declined after lake rehabilitation, which also could be caused
by the increasing water levels.
Fish stocking in village ponds is always harvested in a way that produces income for the village or SAO (Garaway,,
1995) by selling tickets to fish on fishing days and outside of this day, fishing is prohibited but the people are
still allowed to access the pond for agricultural water supply (Chantarawarathit, 1989). Village revenue from the
ticket sales could be as high as 27 000 Thai Baht ha
 and there is a positive relationship between revenue and
yield on a total and per area basis but not revenue and pond area (Lorenzen et al., 1998). Nevertheless, as the
main objective to increase animal protein in the diet of rural people (Suraswadi, 1987). The SAO has to look for
other small water bodies nearby the village to stock fish for the benefit of the communities (DOF, 2007b). Because
if the people, especially the poorest groups, have no alternative, they would suffer the most from the restriction
of access to small water body resources brought about by stocking initiatives (Garaway et al., 2001).
So far, there is no directed study that deals with the socio-economic benefits of stocking programs, either of
indigenous or exotic species, in large water bodies in Thailand. It is suggested that this is due firstly, to the
difficulty to identify the stocked populations from the natural ones, particularly the indigenous fish and Nile
tilapia. Secondly, because of the relatively small contribution of stocked exotic fish, they could not make significant
impact on fishers (Kitivorachate et al., 1985a; Kitivorachate et al., 1985b). Moreover, in terms of income, prices of
the stocked exotic fish are comparatively low (i.e. less than 20 Thai Baht kg
) while the indigenous species
normally cost more than 50 Thai Baht kg
. The financial return in relation to the size at release, which maximizes
fishing income in relation to the cost of stocking, had been studied by Virapat (1993), when it was demonstrated
that the yields and the corresponding benefit gained from stocked Chinese and Indian major carps increased with
size-at-release. He concluded that although stocking of Chinese and Indian major carps in large water bodies in
Thailand are ineffective in purely economic terms, the stocking program obviously has considerable social value
because most fishers are relatively poor and have little opportunity of improving their livelihoods and living145
conditions. However, he also remarked that the benefit gained from the fishery, in terms of revenues, were largely
to the middlemen since they controlled the market system.
In contrast to exotic fish stocking, regular stocking of M. rosenbergii resulted in higher income for the fishers from
catching and selling prawns. Moreover, the high market price of prawns benefits traders at various levels, job
creation and income for all related sectors (Jaiyen, 2005). For example, Sripatrprasite and Lin (2003) reported that
in a run-of-river type Pak Mun Reservoir, which has been regularly stocked with giant river prawn since 1995,
totaling 22 million fry up to 2000, the catches (16 646 kg/yr) contributed 53.8 percent to the total fish catch by
weight, but 97 percent to the economic value of the landings. Similar results were obtained by Renunual and
Silapachai (2005), who found that only with a low recapture rate of 1.8 percent of stocked M. rosenbergii in
Bangpra Reservoir, led to economic profit of 721.64 percent.
Although there are few studies assessing the effectiveness of fishery regulations, especially on the socio-economic
outcomes in the Lower Mekong countries (Baird and Flaherty, 2005), fishers generally agree that conservation
practices benefits them especially in terms of sustaining the fisheries. The main measures, recognized by fishers
were closed fishing areas and season as well as restriction on the use of some fishing gears (Chansri et al., 2008;
Hortle and Suntornratana, 2008). Nevertheless, lack of compliance to the measures is quite common, especially
on using small mesh gillnets. In terms of social objectives, the restriction will directly affect some fishers, who
particularly catch small and mostly low-cost species (Pawaputanon, 1982; Virapat, 1993).
The major constraint on stock enhancement programs and conservation practices relates to institutional aspects.
People (i.e. resource users) are not aware of the importance of such projects (Chantarawarathit, 1989) which could
due to a lack of continuous input by local fishery committees and support from the government, as well as
inefficient transfer of appropriate technology to local operations (ADB, 2005). Moreover, the people have less
participation in the meeting concerning establishment of fisheries measures (Chansri et al., 2008) and this issue
leads to limited investigation of the needs, constraints and expectations of the resource users (Garaway et al.,
2006). Uncertainty regarding the outcomes of stock enhancement programs and conservation practices could also
result from the fact that the underlying biological process is still not fully understood (Garaway et al., 2001). For
example, for stocking programs, De Silva and Funge-Smith (2005) mentioned that the species combinations used
may have been more of a reflection of availability rather than specific knowledge both in small and large water
bodies. Moreover, it is also apparent that, in most of the cases, there was no attempt to correlate the amount
stocked to the potential productivity of the particular water body and which ecological niches should be covered.
Pawaputanon (1982) mentioned that lack of the fundamental knowledge of fish biology and ecology makes it
difficult to establish the appropriate conservation measures for multi-species fisheries as in Thailand. The problems
of implementation of inland fishery measures involve ineffective law enforcement, unclear the boundaries of
some conservation zones and poor information dissemination (Chansri et al., 2008).
There are two specific problems regarding the fish stocking program in Thai large inland water bodies (Virapat,
1993): first, inadequate planning and monitoring of the programs to obtain information on growth and survival
rates of the stocked species and second, no specific time of stocking; it is usually done whenever the fingerlings
are available. Two main factors influence the size chosen for stocking material; cost and survival rates (Welcomme
and Bartley, 1998). Although the optimum sizes of release for yielding high survival rate are recommended
(e.g. Benchakarn and Nookour, 1988; Pawaputanon, 1988; Virapat, 1993), the budget to produce sufficient numbers
for stocking of those sizes is always a limiting factor (see Section 5.3). Another constraint, for fish stocking program
in large water bodies is the lack of program economic viability (De Silva and Funge-Smith, 2005). This is because
this program is not expected to be an income-generating activity but to provide a source of food and to increase
employment through fishery development. Therefore, economic aspects of the program are always neglected
leading to questions on the degree of successful, particularly in terms of economic returns.146
It is clearly seen from this review that although a number of studies have dealt with the results of stock
enhancement and conservation practices, so far, using of the lesson learned (though highly recommended for
further implementation) are scanty mostly due to budgetary constraints and lack of information of individual
water bodies related to the stock enhancement or conservation practices. Stocking program in large water bodies
seem to be not as well organized with inadequate solid scientific bases such as productivity and empty niches
in the ecosystem, optimum stocking density, forage/carnivore ratio and suitable area and season to release the
fish. Performance (biology, ecology and contributions in catches) of the stocked species in large water bodies has
not been seriously studied since Virapat (1993). For conservation practices, although there is the recent work by
Srinoparatwatana (2009) and including previous studies, solid conclusions could not be retrieved from these in
terms of a quantitative approach. This is due to the questionable economic viability of many programs (De Silva
and Funge-Smith, 2005). Therefore, to cover the economic viability and investigate the benefit-gain to people
(or resource users), especially for the purpose to improve the living standard of fishers, more and improved
socio-economic studies of the results from stock enhancement and conservation practices should be carried out
simultaneously with the existing programs. Moreover, alternative sources of income for the fishers during the
closed season and area should be implemented by the authorized organizations
For the fish stocking program in large water bodies, it is clearly seen that the current yield of the stocked exotic
species is low compared to the native ones. Therefore, indigenous species, such as Smith barb P. falcifer, should
be a good candidate for stocking since they are capable of establishing breeding populations and forming
fishable populations within the system. Appropriate size at release and stocking density of individual species must
be examine and monitoring program to obtain information of growth and survival rates of the stocked species
must be initiated. Moreover, stock enhancement should be performed by using brood stock that have the most
genetic similarity to wild populations (stock). In small water bodies, indigenous self-recruiting species that can
tolerate the local conditions (e.g. low dissolved oxygen and high turbidity), such as snake-skin gourami T. pectoralis
should be tried. Before stocking, suitable period and locations to release the seed fish should be determined.
In terms of institutional aspects, participatory adaptive learning, involving external agencies working with local
communities should be expanded. This process provides for an increase in knowledge about the resource systems
and enables the refinement of management policy, which will likely be ultimately better accepted by the
communities (Garaway  et al., 2001). Lastly, academic capacity building of the DOF and authorized staffs
should be considered. For DOF, most of the staff were trained in aquaculture, and lack skills in inland fisheries
management and have little experience in the field of ecological principles underlying inland fisheries production.
This situation is not conductive to good management of the resource, and contributes to neglect in management
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Bui The Anh
 and Phan Dinh Phuc
Key words: Inland fisheries, resource enhancement and conservation, Icefish, Prochidolus lineatus
1.1 History of inland fisheries resource enhancement and conservation in Vietnam
According to the assessment of MONRE (2003), Vietnam has a dense river network, including 2 360 rivers with
a length over 10 km. Eight have large basins with catchments of more than 10 000 km2
. This river network
includes many international rivers that originate in other countries (MOFI and World Bank, 2005).
The total water surface potentially available for aquaculture, inland or culture-based capture fisheries has been
estimated at 1.7 million ha (MOFI and World Bank, 2005). Of this total, around 120 000 ha are small ponds, lakes,
canals, gardens; 340 000 ha are large water surface reservoirs (Nguyen, 1994; Ngo and Le, 2001); 580 000 ha are
paddy fields which can be used for aquaculture purpose, and 660 000 ha are tidal areas (IFEP, 1997). However,
these figures do not include the water surface of rivers and about 300 000-400 000 ha of straits, bays and lagoons
along the coast (MOFI and World Bank, 2005). The number of reservoir must be higher because many new
reservoirs have been constructed in recent years.
Vietnam has a very high biodiversity in aquatic resources with 1 027 freshwater fishes (belonging to 97 families)
(Nguyen and Ngo, 2001), 1 438 micro algae, more than 800 invertebrate species. It diversifies with much kind of
groups such as freshwater fishes, invertebrates and migratory species. There are some high value freshwater fish
species that fetch prices as high as marine fishes such as Hemibagrus species.
In the past, freshwater capture fisheries were important for the economy in many regions and important food
source for the Vietnamese people and the soldiers (Dinh, 1995; Bui, 2006). The government (GoV) was the
exclusive harvesting sector for all reservoirs (Ngo and Le, 2001). In the 1970s, there were more than 70 fishing
cooperatives with annual production of several thousand tonnes. However, this system collapsed due to
over-exploitation of resources change in the country’s economic system (Ngo and Le, 2001; Bui, 2006), which
caused a reduction in the resource and most cooperatives of fishers changed their operation to other activities
at the end (Dinh, 1995).
There are several threats that directly impact the diversity of inland resources and ecosystem such as
over-exploitation, development of agricultural areas to industrial zones, pollution, overutilization of the water
supply system caused changed in hydrography, construction of new dams/reservoirs, etc. (MARD, 2009).
However, inland fisheries in Vietnam still play an important role as a source of food, creating job opportunities
and sustaining the livelihood for most of people in rural areas. Any changes from these resources would cause
the influence to people in the regions. The annual statistics, presented by the Government’s Statistics Office
Aquatic Resources and Inland Fisheries Department, Research Institute for Aquaculture No. 1, Bac Ninh, Vietnam;
E-mail: atbu@ria1.org
Central Plateau Broodstock Center, Research Institute for Aquaculture No. 3, Daklak, Vietnam; E-mail: phucdinhphan@
presented a peak of 244 000 tonnes of fish in 2001, declining to 209 000 tonnes in 2003, probably due to drought.
Although inland fish production has contribution from culture-based fisheries activity through the stocking of
lakes, dams and other inland waters, mainly with carps and tilapia, but fish consumption was still very low at
14 kg/person based on the FAO fish consumption survey (Lem, 2002).
Figure 1 showed that capture fisheries production has not developed very much in the last 30 years (FAO, 2007).
This could be due to the strong aquaculture development in Vietnam in the last three decades. In 1980s-1990s,
fisheries production was stable due to the existence of government intervention. However, the figure also pointed
out that the contribution of the private sector in inland fisheries could be more visible since 1990s as mentioned
by Nguyen and Nguyen (2000), Nguyen (2001) and Bui (2006).
Figure 1.  Contribution of the inland capture to the total inland fish production of Vietnam (FAO, 2007).
200 000
400 000
600 000
800 000
1 000 000
1 200 000
1 400 000
Inland capture Total inland % capture inland
Production (mt)
Percent (%)
Basically, inland fisheries resource enhancement has been considered a major component of reservoir fisheries
management since 1962 (Nguyen, 2001). Multipurpose reservoir construction commenced about the 1960s for
irrigation, hydropower generation, flood control, etc. (Dinh, 1995; Ngo and Le, 2001; Bui, 2006; Phan, 2006).
Reservoir fisheries is always a secondary or tertiary activity and are given low priority (Ngo and Le, 2001; Bui, 2006).
However, Bui (2006) and Phan (2006) reported that the government had issued policies to utilize the reservoir
water resources for fishery activities, both as a means of increasing fish food supplies in rural areas, and as an
avenue for employment for displaced people. Inland fisheries resource enhancement aims to increase the fish
production in the related water bodies due to poor natural fish stocks and low nutrition. Therefore, a large number
of state fisheries agencies were set up in order to produce mass stocking materials for all the reservoirs. However,
due to economic crisis and the consequent termination of subsidies by the Government to the stocking program
(Nguyen and Nguyen, 2000; Nguyen, 2001), reservoir fisheries has been affected seriously. Many governmental
sponsored fisheries companies could not continue their own activities without subsides and thus were
abandoned. Stocking program stopped for all reservoirs in the period of 1990s (Nguyen and Nguyen, 2000;
Nguyen, 2001; Bui, 2006) due to the economic crisis.
According to Nguyen (2001), stocking fish to the reservoirs can improve quality of fish fauna, increase reservoir
productivity, and hence increase fish yield. Recently, the Government has restarted the stocking program for some
reservoirs including the newly constructed ones such as Tuyen Quang reservoir, Son La reservoir with the aim
to develop fisheries activities and create new opportunities in the regions. The government also established
co-management models to manage the fisheries and fisheries resources in some inland water-bodies.155
Vietnam was the 50
 country in the world that signed in the Ramsar Convention in 1989. In 1993, Vietnamese
Government again signed the International Convention on Biodiversity in Rio de Janeiro (Brazil). This convention
was approved by government assembly in October 1994. These are the two basic conventions on biodiversity
and resources conservation in the world that Vietnam had joined.
The Vietnamese Government has done many statistical researches or status assessments on biodiversity in order
to plan for the conservation and utilization of the natural resources based on the above conventions.
In 2008, the Prime Minister approved the decision No. 1479/Q D-TTg for the establishment of the water inland
conservation zones until 2020. There are 45 conservation zones being established under this decision, including
16 national conservation zones and 29 provincial conservation zones.
1.2 Major practices of fisheries resource enhancement and conservation
In Vietnam, stocking has been considered a major component of reservoir fisheries management (Nguyen, 2001).
The technology of artificial breeding of cultivated fish species has been successfully applied and provides
opportunity for supplying mass stocking material. In the past, there were several hatcheries built around the
reservoirs in order to produce fingerlings to be released into new reservoirs. The fingerlings were stocked into
reservoirs as the annual work plan of the state fisheries enterprises/cooperatives. Capture fisheries activities in
the water bodies were managed by state fisheries agencies to catch fish.
In addition, Dinh (1995) reported that by the application of new fishing technology from China, such as the use
of trammel and integrated nets, the fishing techniques were improved and contributed to higher yields. Annual
yields of 26 tonnes, 108 tonnes and 47 tonnes were reported in Tam Hoa, Cam Son and Thac Ba reservoirs in 1971,
1974 and 1978 respectively. During this period, the state fisheries agencies had planned seasonal capturing
calendar according to the set regulations and that no one has the right to catch fish in the reservoirs/lakes
without state workers.
Among cultivated species, silver and bighead carps are the most suitable species to release into reservoir. These
species could utilize the rich nutrients and conditions of the reservoir water. Nguyen (2001) demonstrated that
cultivated species contribute 30-90 percent of total catch of the reservoir, fish production is closely related to
stocking density and recapture rate. Bui (2006) indicated that higher yield could be obtained after two years of
After 1993, many reservoir fisheries all over the country had collapsed due to the economic crisis and the changes
in reservoir fishery policies of the Government. Most of the small and some medium-sized reservoir were leased
to the private sectors for culture-based fisheries. However, all large-sized reservoirs were still managed by the
government. So there were big changes in the stocking program for these reservoirs. The small and medium-sized
reservoirs applied new stocking composition and technology similar to that for big ponds. Traditional species such
as silver carp, bighead carp, Indian major carps, common carp, grass carp and silver barb were stocked for culturebased fisheries. It totally changed the view on reservoir fisheries production in the last 10 years. The government
had realized that reservoir fisheries could play an important role in increasing freshwater fish production to supply
high protein food for the people and create job opportunities for the poor and displaced people (Phan and De
Silva, 2000; Nguyen, 2001). Therefore, it was a government policy for the period 2000-2010 to develop reservoir
fisheries and the target is to produce 200 000 tonnes of fish of which 20-25 percent fish products should be
suitable for export. The Government expected these activities would provide employment to 75 000 people.
In the large-sized reservoirs, the stocking composition had changed to have more species such as silver barb,
common carp, Indian major carps, grass carp, and some other species such as  Prochidolus lineatus (which
introduced from South America), icefish. Recently, MARD wants to introduce high value native species into these
reservoirs like Hemibagrus guttatus. Nowadays, the government changed its policy to stock fishes for some new
reservoirs (Tuyen Quang or Son La hydropower reservoirs) instead of leaving this activity to the local government
as previously practices. There was a 5-year project approved to release fingerlings at the Tuyen Quang reservoir
from 2010-2015. In parallel, Son La reservoir was applied for a long term stocking and reservoir fisheries
development program by using the fund from revenue of power generation. The government is considering this
plan to allow fisheries agencies to have a certain percent of this fund from the hydropower plan.
Stocking of Chinese major carps has contributed to reservoir fisheries in Vietnam significantly. Fisheries
enhancement in Thac Ba reservoir, northern Vietnam is a good example.
Thac Ba reservoir (23 500 ha) is located about 170 km west of Hanoi. It was constructed by impounding Chay
River (one of the tributary of Red River) commencing in 1962 and finishing in 1970 primarily for hydropower
generation. Thac Ba reservoir was the first hydropower generation built in Vietnam and was recorded as an
important reservoir to supply food production and employment opportunities to the people in the vicinity
particularly the displaced people (Dinh, 1995; Nguyen, 2000; Bui, 2006).
In this reservoir, 90 percent of the fish species caught are Cyprinidae. The most common species caught are
Toxabrami s  houdeme r i , Ps eudohemi cul te r  di spar, Cul t e r   e r  y thropte r us,  E r  y throcul t e r  s p p. ,  c ommo n   c a r p,
Hemiculter leucisculus, Carassioides cantonensis with the rarely contribution of exotic species.
In the 70-80s, fish production steadily went down and drop rapidly since 1990. However, with the changes to
market driven economy coming with reduction of state management, the contribution of the private sector to
reservoir fisheries rapidly increased. Accordingly, due to the increase in the number of fishers and fishing gears,
the fish production doubled (about 600 tonnes yr
) (Nguyen, 2000; Bui, 2006).
With the above features, the reservoir fisheries provided a significant contribution to nearly 300 000 people
(Nguyen, 2000) living in the vicinity to utilize the reservoir resources and create a new livelihood for poor people,
particularly for displaced people.
In this reservoir, stocking program mainly based on silver carp and rohu (Labeo rohita) amd grass carp, silver barb
had been stocked as trial species in 1997-1998 and 2000, respectively. After a long time of not stocking, the
reservoir has been re-stocked with 250 thousands to 760 thousand fingerlings in 2003 and nearly 700 thousand
in 2004 (Nguyen, 2000; Nguyen, 2001; Bui, 2006).
Recently, there are two exotic species (icefish and Prochidolus lineatus) successfully stocked into the reservoir, but
its impact has not been fully recognized and studied.
In case of icefish (Neosalanx tangkakii), this species grew and developed rapidly after four year of stocking.
With the fish production of about 30-40 tonnes in 2008 (Nguyen Hai Son, private communication), this species
could contribute as a major source for Thac Ba reservoir fisheries. However, without any management activities,
this fishery is going to collapse and witness rapid reduction in fish production.
Icefish has been known as a small fish eating zooplankton (Cladoceroms, Leptodora, Calanoid copepods và
Cladoceromd). In 2002, 112 million eggs were released into Thac Ba reservoir (appx. 23 500 ha) by the Chinese
enterprise. There was a commercial proposal submitted to the local government about the high value and visible
economic benefit of stocking this species into the reservoir. With the initial assessment on reservoir environment
by the Chinese experts, it was recommended to stock this species into the reservoir. However, this process took
a long period (about 3 years) to get approval from local government.
In 2003, very little fish was found in the reservoir. However, by 2006-2007 fishes were found everywhere and more
concentrated in the centre and upstream area of the reservoir. Fish were caught by using lighted lift-net and seine
net with the mesh size about 0.5-1 cm. According to Nguyen (2010, personal communication), CPUE of icefish is
about 150-200 kg/day for 12-15 day a month.
In 2007, icefish production was estimated to be about 50 tonnes and reduced to about 40 tonnes in 2008 (fish
yield contributed about 5 percent, but its value is about 25 percent). It was even worse in 2009 with very few
icefish caught due to over-exploitation and open access on this resource. This phenomenon has been well
recognized in China but it has not been fully assessed in Vietnam.157
It was found that icefish has two populations in the reservoir and it reproduces twice a year, in August and
February. The government is currently funding a study on icefish impact assessment in order to identify about
the fish biological and reproduction features and aims to introduce this species into other reservoirs which has
similar physical and ecological conditions as the Thac Ba reservoir. However, more time is needed to fully
recognize the impact assessment results on this species.
Another species could be considered as a potential fishery in the reservoir is the  Prochidolus lineatus. In 2003,
this species has been illegally transplanted into Vietnam from Brazil through China. However, local people did not
know about its origin so they called it as Yangtze mud carp (local name: cá Trôi tru’ò’ng giang). The tracking of
this fish origin started in 2007 with the funding from the government. The study revealed that the fish truly
originated from Brazil (Bui et al., 2009).
This species is found in many inland water bodies such as rivers, ponds, lakes and reservoirs, which was either
released by the local government or escaping from cages or released by farmers. It can survive in the very cold
winter in Vietnam. The fish is easy to reproduce with high survival rate (70-80 percent) and now every hatchery
can produce seed of this fish, especially in low land area. It is easily used for poly-culture in pond with the stocking
density about 2 fish/m2
, usually at a ratio of 70/30 with grass carp and tilapia (Bui et al., 2009). Total production
of the fish has not been estimated but only Bac Giang province harvested 200 tonnes in 2008. This fish fetches
quite good market price of about 1 USD/kg.
Recently studies on this species found that Thac Ba reservoir has this species. It was stocked into reservoir by the
local fisheries agency in 2005 (Bui et al., 2009). A lot of information revealed that this species easy spread out and
could be a dominant species in the water body. Bayley (1973), Capeleti and Petrere (2006) described this species
(Prochidolus lineatus) having highest production in Pilcomayo River. In 1987, the most species caught in Cachoeira
de Emas of Mogi-Gaucu River was  Prochidolus lineatus, contributing about 90 percent of the capture yield
(Petrere, 1989).
Currently, in Thac Ba reservoir, it just contributed about 2-3 percent of total catch in the reservoir (Bui et al., 2009).
So it should be considered to culture this species in the natural water bodies such as rivers and reservoirs or lakes.
However, this species is widely spread in the low land areas as a common cultivated species in ponds and it could
multi-culture with other species in ponds. This species is now put into a research program of MARD to assess the
impact and potential of releasing it in the reservoirs and other water bodies in Vietnam.
Presently, there are no activities on river enhancement implemented in Vietnam. However, there is an exception
where China has collaborated with some provinces of Vietnam located along the border to release fishes into
rivers. The places are in the border area between the two countries and the impact of this activity has not been
On the conservation activities, the government had funded many programs to protect the gene sources of high
value and endanger species in situ. According to Department of Science and Technology-MOFI study (2001),
37 species has been protected and the gene sources are kept in the three Research Institute for Aquaculture 1,
2, 3 in Vietnam (Table 1). Besides, the government also funded to study artificial propagation on some endangered
species. To date, three species have been successfully reproduced and the technology has been transferred to
the local fisheries agencies in Vietnam (Table 2).
Recently, the Prime Minister of Vietnam has just approved a program to establish decision No. 1479/Q D-TTg for
the establishment of the water inland conservation zones until 2020. There are 45 conservation zones being
established under this program, including 16 national conservation zones and 29 provincial conservation zones
in all over the country. This program aims to maintain and protect the biodiversity of inland aquatic resources
of Vietnam.
Table 1.  The list of protected fishes maintained in national broodstock and research centres in
No. English name Scientific name
1 Cá Ba sa (Vietnamese) Pangasius bocourti
2 Marble goby Oxyeleotris marmorata
3 Mad barb Leptobarbus hoevenii
4 Common carp Cyprinus carpio
5 Hungarian common carp Cyprinus carpio
6 Hungarian common carp Cyprinus carpio
7 Indonesian common carp Cyprinus carpio
8 Vietnamese common carp Cyprinus carpio
9 V1 Vietnamese strain common carp Cyprinus carpio
10 V1 Hungarian strain common carp Cyprinus carpio
11 V1 yellow strain common carp Cyprinus carpio
12 Catla Gibelion catla
13 Red tailed tinfoil Barbonymus altus
14 NA Hemibagrus guttatus
15 Giant snakehead Channa micropeltes
16 Vietnam silver carp Hypophthalmichthys harmandi
17 Silver carp Hypophthalmichthys molitrix
18 Bighead carp Aristichthys nobilis
19 Java barb Barbonymus gonionotus
20 Mrigal Cirrhinus cirrhosus
21 Snakeskin gourami Trichogaster pectoralis
22 Giant gourami Osphronemus goramy
23 Striped catfish Pangasianodon hypophthalmus
24 Black carp Mylopharyngodon piceus
25 Grass carp Ctenopharyngodon idellus
26 Whitespotted clarias Clarias fuscus
27 North African catfish Clarias gariepinus
28 Bighead catfish Clarias macrocephalus
29 Mud carp Cirrhinus molitorella
30 Climbing perch Anabas testudineus
31 Rohu Labeo rohita
32 Blue tilapia Oreochromis aureus
33 Nile tilapia Oreochromis niloticus niloticus
34 Viet strain tilapia Oreochromis niloticus
35 Thai strain tilapia Oreochromis niloticus
36 GIFT strain tilapia Oreochromis niloticus
37 Egypt-Swansea strain Oreochromis niloticus
Note:  NA – not available159
2.1 Inland fisheries resources enhancement
During the past ten years, the inland fisheries resource enhancement practices have not changed. As discussed
above, it was basically implemented in the reservoirs and based on the size and management schemes in each
situation. Ngo and Le (2001) indicated that the latter was more oriented on production rather than on
management. There were no strong links between the different sectors using the water resource for various
purposes such as irrigation and/or industry. According to Ngo and Le (2001), the inland fisheries resource
enhancement could be categorized into two types:
 Reservoir fisheries enhancement, and
 Culture-based fisheries
2.2 Reservoir fisheries enhancement
The activities of this type are mainly based on Government activity and orientation and could be under the
management of the local government and state enterprise. This activity is always applied for large and mediumsized reservoirs where there is a large number of  people/community living around the reservoir. Fisheries
enhancement, therefore, would provide job opportunities to people in vicinity, develop the socio-economic
condition of the region and provide food for poor people.
In some large-sized reservoirs, which are mainly constructed for hydropower generation, stocking program is
controlled by the local government with the orientation from central government. Thac Ba reservoir is an example
(Figure 2). Stocking program is funded by local government and fishers must register to the fisheries center to
get fishing license for catching fish in the reservoir. But it only works with the big fishing gears because these
people are working everyday in the reservoir while other people living around were just using small boat and
simple gears to catch fish. There is another way to control these people. Commune committees are authorized
to collect fishing fees from the fishers living in the commune based on their fishing facilities such as the size and
Table 2.  List of endanger species in conservation program in Vietnam
No. English name Scientific name
1 Reeve’s shad Tenualosa reevesii
2 Chinese gizzard shad Clupanodon thrissa
3 Konoshiro gizzard shad Konosirus punctatus
4 Drápenka ˘siroká (Czech) Onychostoma laticeps
5 Labeo znamenané (Czech) Semilabeo notabilis
6 NA Similabeo rendahli
7 Cá Hoa (Vietnamese) Bangana tonkinensis
8 NA Similabeo graffenili
9 Spiny barb Spinibarbus hollandi
10 Spiny barb Spinibarbus denticulatus
11 Mahsír hongkongsk´y (Czech) Folifer brevifilis
12 Black carp Mylopharyngodon piceus
13 NA Hemibagrus guttatus
14 Black Amur bream Megalobrama terminalis
15 Helmet catfish Cranoglanis bouderius
16 Goonch Bagarius yarrelli
17 Four-eyed sleeper Bostrychus sinensis
Notes: Bold names are species successful with artificial propagation; NA – not available
number of boats owned, total amount of gear used (by type) and number of cages operated (Bui, 2006; Bui
et al., 2008). A part of the collected income will be given to the community and the remaining will constitute the
local government tax (Nguyen, 2000; Ngo and Le, 2001). In turn, the local government will pay for the wages of
the personnel while the centre will bear all costs associated with stocking and extension activities in relation to
aquaculture operations.
However, in some large and medium-sized reservoirs, the enhancement activities are carried out by local fishery
enterprises. They stock the fish into the reservoir and control the harvesting activities. This could be observed in
Tri An (Figure 3), Nui Coc and Dau Tieng reservoirs. The advantage of this management pattern is that the
enterprise has the official ownership of the fish resources. A production plan is initiated by the enterprise
depending on their investment capacity and market availability. However, the disadvantage of this type is that
it cannot stop illegal fishing due to the large reservoir area and difficult morphology.
The enterprise sells daily and/or periodical fishing licenses to prospective fishers depending on the type of the
gear. The income from the sale of licenses is utilized for staff salaries, running costs, taxes and fingerlings stocking.
Accordingly, the enterprise has major socio-economic links with the surrounding population whose livelihoods
are dependent on the fishery resources in the reservoir. Although the right of fishery management has been
transferred by provincial authorities it has no obligations with regard to the conservational aspects of the flora
and fauna of the reservoirs. Also, there is potential conflict between different water users, particularly between
tourist agencies, irrigation units and fishers.
The last type of fisheries enhancement is carried out in some hydropower reservoirs such as Hoa Binh, Ke Go and
Cam Son reservoirs (Figure 4). This is open access fishing. The local fisheries agencies only have administrative
jurisdiction on area, water use, and transportation, and let fishers access freely the reservoir resources. No
particular fishery management activities are in operation and stocking just restarted in the last few years.
annual workplan
annual workplan 
power generation 
and water control
control illegal fishing
annual workplan
pay tax
Invest on stocking
selling levy
operation cost
annual workplan  annual workplan 
Ministry of 
agriculture and rural 
Ministry of industry
and trade 
Dept. agriculture
and rural
Fisheries centre
District people
Commune people
revenue return to fish stocking
pay tax
el vy co ect oi n
Figure 2.  Schematic representation of government arrangements managing fisheries and enhancement in large
and medium-sized reservoirs in Vietnam161
Figure 3.  Schematic representation of fisheries management and enhancement of local enterprise in Vietnam
Fishers Reservoir
Dept. of Fisheries
Dept . of Aquatic 
annual workplan
Ministry of
Agriculture and
Rural Development
annual workplan 
power generation 
and water control
control illegal fishing
fish stocking
Ministry of 
Industry and Trade 
annual workplan  annual workplan 
Dept. of Agriculture
and Rural
levy collection Hatchery
against cutting reservoir
build small dams 
in the reservoir
Provincial government 
Patrolling unit
Fisheries company 
keep fishers away
from conservation zone 
Dept. of Agriculture
Rural Development  
conservation zone
Irrigation unit
water supply management
water supply
Ministry of
Agriculture and
Rural Development  
action plan
Ministry of Natural
Resources and
action plan
Dept. of Natural 
and Environment  
open access
Figure 4.  Schematic representation of open access reservoir fisheries in Vietnam
In this form of management, there are several organizations that share the waters but fisheries never have the
highest priority over the control of the resource. There are conflicts between the official organizations on fishery
resources management. As consequence, an open access policy to the water is still maintained.162
2.3 Culture-based fisheries
In the last decade, culture-based fisheries had been done in some small-sized reservoirs which had been built
for enhancement purposes as well as supplying seed to neighboring farmers (Nguyen, 2006). However, based on
the 10-year development plan to obtain a production level of about 50 000 tonnes from reservoir fisheries, most
of small irrigation reservoirs in Vietnam now are leased to farmers, farmer group or local organizations to conduct
culture-based fisheries activities (Nguyen, 2006). These people run business together including stocking,
harvesting and marketing.
In this type of fisheries, stocking normally starts from April to June when the water level is high. According to
Nguyen (2006), stocked fishes depends mainly on availability in the regions and proximity to the supplies, and
generally include common species such as grass carp, silver carp, bighead carp, mrigal and silver barb. In these
reservoirs, people prefer using silver carp and silver barb more than other species with 40-50 percent of stocking
composition. Sometimes, farmers stock high value species such as snakehead, Hemibagrus guttatus, etc. Fish is
harvested during March to May because the water is used for paddy culture during this period. Nguyen et al.
(2001; 2005) have shown that stocked species contribute more than 80 percent of total weight at harvest.
It was observed that high variations between reservoirs related to the size of each reservoir and generally, yields
were lower in the larger reservoirs (Nguyen et al., 2001). Nguyen (2006) found that most small irrigation reservoirs
are seen as appropriate for developing culture-based fisheries in Vietnam. Therefore, culture-based fisheries could
provide a means for producing cheap source of animal protein to meet the increasing demand for food in rural
areas of Vietnam.
2.4 Inland fisheries resource conservation
According to the assessment of MONRE (2003), Vietnam has a dense river network, with several types of inland
water bodies such as running water bodies (river, stream, estuarine and channel) and close water bodies (lake,
reservoir, pond, swamp, paddy filed, etc.). Inland water body resources of Vietnam are very diverse with high
biodiversity of flora, fishes, invertebrate, etc. Furthermore, Vietnam morphology is related with other countries
which make up the biodiversity of the fauna in the country.
A new policy on resources conservation has been issued to different ministries such as the Ministry of Natural
Resources and Environment (MONRE) is now responsible for Ramsar areas and the Ministry of Agriculture and
Rural Development (MARD) is responsible for Inland Fisheries Resources Conservation zones. There are still some
conflicts between these two ministries because of overlapping areas/zones. However, MARD manages all activities
related to aquatic resources and coordinate other related activities with other organizations.
Figure 5 shows the schematic on management framework of the inland conservation areas in Vietnam. There are
two management levels, the national and the local management level. The criteria to select and determine
conservation zone is the same between these two levels. Except specific zones, the local government controls
all the conservation zones located in their administration area. MARD only take the administrative works on the
large conservation area at the national, inter-province and inter-country levels.
The National Steering Committee on Marine and Inland Conservation areas belongs to MARD. It is responsible
in coordinating, , formulating government policies, decide and approve the annual work plan. MARD heads this
committee which consists of representatives from the Ministry of Public Security, the Ministry of Education and
Training, the Ministry of Planning an Investment, the Ministry of Science and Technology, the Ministry of National
Defense, MONRE, the Ministry of Finance, the Ministry of Trade, Ministry of Culture and Information, the Hanoi
National University, the Hochiminh National University, the Department of Tourism, the Vietnam Institute of
Science and Technology and the Coordinating Office (Department of Department of Capture Fisheries and
Resources Protection-MARD). The mission of Coordinating Office is to coordinate the activities, monitor and assess
the effects, support and monitor the financial activities and propagate and collate the constructive ideas.163
The Provincial People Committee (PPC) receives advice from the Department of Agriculture and Rural
Development (DARD) who directly manage the conservation area in the province. Under DARD, there is
a management unit to control all activities in the areas.
There are also international donors and NGOs involved in the research activities in conservation areas of Vietnam.
These organizations provide funding and technical supports and build projects.
Although inland fisheries conservation recently has received more attention from the central government of
Vietnam, but the impact assessment on natural population has not been fully realized and implemented carefully
in Vietnam.
Many inland water bodies are still facing issues of illegal importation and release of alien species. The example
of Prochidolus lineatus species is a very clear example. Without tracking the right origin of the introduced species,
the mangers or farmers could make it to be a bigger issue when the species dominate the area. It may affect the
indigenous species and other fisheries in the area. Such of illegal transplantation should be controlled seriously
and strictly in order to preserve the biodiversity of the inland water bodies in Vietnam.
The unsustainability of icefish fisheries development in Thac Ba reservoir could affect other fisheries in the
reservoir and the local socio-economic conditions. The wide application of lift-net to catch icefish in the reservoir
could also catch a lot of small fish, which are at the larvae or fingerling size, to directly affect other fisheries. In
addition, the impact on ecosystem of this species should be assessed to determine its effects to other species.
For example, this species eats zooplankton (Cladoceroms, Leptodora, Calanoid copepods và  Cladoceromd) so it
could compete the food with other species in the reservoir.
In the last 10 years, the Government of Vietnam has tried to conduct studies on indigenous species. They have
funded for many research programs to preserve the native stock species and multiply these species in their
national hatcheries and research centers. Presently, Vietnam has successfully reproduced some indigenous species
and currently, they have a plan to re-stock them in the wild and some medium-sized reservoirs such as Nui Coc
or Na Hang reservoirs to conserve its stock in wild.
Note:  dashed line: subordinated relation; stroke line: guidance relation
Figure 5.  Management frame work of the inland conservation zones in Vietnam
Inland fisheries conservation 
national steering committee
(located in MARD)   
Steering committee
(Central Office) 
Central level
Provincial level
National conservation
zone steering committee 
Provincial conservation
zone steering committee 
Relation Ministries
Provincial People
Committee 164
Moreover, the central government has established many conservation zones to maintain and increase the
population of these species in the wild. Besides, these areas could be the best way to conserve the biodiversity
of the inland water bodies.
It is a very clear that inland fisheries bring more opportunities to the fishers and people living around in the area
of such water bodies. Bui (2006) demonstrated that a number of fishers increased rapidly when the private sector
is allowed to join together with the state fisheries. Figure 6 shows the trend of the private sector in Thac Ba
reservoir fisheries. However, present fish production data is just recorded by the state so it could not described
exactly of the private sector contribution.
According to Bui (2006), currently the fish production of this reservoir could get up to over 700 tonne a year and
it only comes from private sector contribution, which are now about more than 2000 fishers. Also, in the recent
study Bui et al. (2008) pointed out that the main income of fishers are from reservoir fisheries. This demonstrates
that reservoir fisheries are the secondary priority but they bring a lot of opportunities to the local people. It also
provides foods and low-cost feed ingredient to the local livestock and cage culture/aquaculture activities
(Bui et al., 2008).
Figure 6.  Relationship between number of fishers and fish production in Thac Ba reservoir (Bui, 2006; Bui et al.,
No fisher 900
Fish production
Fish production (tonne)
Number of fishers
Although the Vietnamese government had issued many decisions, plans and policies to improve the inland
fisheries resources enhancement and conservation in recent years, it has not still achieved many good results. This
could be due to the overlapping in management responsibilities, lack of adequate information and the merging
of the management organizations (Ministry of Fisheries merged into MARD). Consequently, the information is still
scattered and not continuous.
Besides, there has been no good species introduced or released into reservoirs/lakes/rivers in the last two decades,
except the traditional species. This fact can not change the figure to increase fish production in the water bodies.
Artificial propagation techniques on several fish species are very popular and easy for farmer to learn and this
helps in the aquaculture sector but also competes with the state supply system. State hatcheries located around165
the reservoirs are finding it difficult to develop and maintain their role in the region. These hatcheries have been
impacted by the strong development of the private sector.
There are some successful programs with some indigenous species, which have been done with high values
species. But, the technology is still in small-scale and need to be transferred all over the country.
As the above discussions, there is an overlap in the fisheries management systems of Vietnam. The conflicts
between two or several organizations managing the reservoirs/rivers still exist and there is still no good solution
to this problem. It is also the same with the management in several conservation areas. The overlapping role or
work between the two organizations will cause the collapse of the system. It causes the directions go in the
wrong ways and wastes government investment.
Moreover, the conflicts between the water users such as fisher and fisheries agencies in sharing and utilizing
resources are also a constraint. Some conservation areas ban people harvesting fish in their area, even it is allowed
(that is the forestry conservation zone) because the manger brings them in a group of thefts. The poor
coordination between the management organizations also brings a lot of troubles to fishers when they need to
contact these units. There is no proper legal document from these organizations to instruct local people what
to do.
Although there are quite a lot program to assess about the impacts of environment and biodiversity, the
information is still lacking to provide for decision maker and other relevant organizations to build the policies
and programs on resources conservation in Vietnam.
Due to some constraints and problems above, there are some recommendations needed to be considered:
 Government need to improve the framework of management organizations in order to reduce the
overlapping jurisdiction and/or responsibilities in the future implementation;
 More studies should be carried out on selecting good species to replace the common fishes currently
stocked to increase the fish production and its value; (give some more valuable impacts)
 There should be certain control on introduction new species to Vietnam.
 The environmental and biodiversity impact assessment activities should be concentrated to keep the
balance for the inland resources of Vietnam.
 There is need to carry out studies on estimating the quantity of the available water bodies/reservoir
which could be utilized for fisheries development and build up the development program in the future
based on such studies.166
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Sena S De Silva
Network of Aquaculture Centres in Asia-Pacific,
Bangkok, Thailand
In contrast to stagnant marine capture fisheries in the past two decades or more, it is now widely acknowledged
that in capture fisheries the greatest potential for growth lies in the inland sector (FAO, 2008), and realisation of
this potential would also impact on rural livelihoods and nutrition of rural masses in developing countries in
particular. Admittedly, the inland fishery sector, until now has not attracted the attention it should have, in many
fronts, such as in gearing government policies, research and development efforts, technologies and marketing
among others.
Inland fisheries in developing countries are for food fish production, as opposed to those in developed countries
which are primarily for recreational purposes (Welcomme, 1997; Welcomme and Bartley, 1998). As such the
development strategies that will drive these two types of fisheries are different, with some commonalities,
FAO (1997) defines fisheries enhancements as technical interventions in existing aquatic resource systems, which
can substantially alter the environment, institutional and economic attributes of the system. This is the process
by which qualitative and quantitative improvement is achieved from water bodies through exercising specific
management options. In addition to the above is the enhancement of fish populations through stocking, either
using hatchery produced seed or wild collected seed (e.g. freshwater eels), for varying purposes. Accordingly, such
interventions, direct and indirect management enhancements (e.g. introduction of closed seasons, habitat
improvements etc.) may result in enhanced fish production through capture fisheries, culture based fisheries, etc.
Enhancements may also lead to biodiversity conservation through the establishment of “conservation units”,
sanctuaries and other managerial measures referred to earlier.
Inland fisheries resource enhancement and conservation have been practiced in the region by many countries
for various purposes for decades. However, the practices, management and effectiveness vary greatly country from
country due to constraints in knowledge, resources and institutional setup. Fisheries resource enhancement and
conservation not only contribute to supply of fish products and generate livelihood for the population mass in
the inland areas, but also have significant impacts on aquatic biodiversity and ecological functions of inland water
bodies. However, aspects on stock inland fishery enhancements in the region have received limited attention
previously (Petr, 1998; De Silva and Funge-Smith, 2005). The current synthesis is based on a FAO regional review
study on fisheries stock enhancement and biodiversity conservation covering ten Asian nations (Bangladesh,
China, India, Indonesia, Myanmar, Nepal, Republic of Korea, Sri Lanka, Thailand and Vietnam) which formed the
basis for the FAO regional consultation conducted over a four day period in February 2010. This consultation had
the following objectives:
 Exchange and share successful experiences and lessons on inland fisheries enhancement and
conservation practices across the countries participating in the review study,
 Assess the impacts of inland fisheries resource enhancement and conservation practices, identify the
constraints and related problems from a regional perspective, and
 Recommend regional collaborative activities to promote improved practices of inland fisheries resource
enhancement and conservation.
This synthesis should be read in conjunction with the country reviews that are included in this volume. The country
reviews are not specifically referred to in the text, however.170
In addition, relevant, additional published information on the subject was utilised in the preparation of the
synthesis. In order to place the material in a proper perspective the synthesis also deals with the current status
of inland fisheries in the region and its contribution to the global inland food fish supplies, and including a brief
summary of the current inland fishery practices.
The earth is estimated to have only 35 029 000 km3
of freshwater, or only 2.5 percent of all water resources, of
which only 23.5 percent is habitable (Shiklomanov, 1993, 1998; Smith, 1998). The amount of freshwater available
as rivers, lakes, wetlands etc. amounts only to 0.01 percent of the earth’s water resources or only 113 000 km3
Generally, a fact that is often not appreciated is that, of the world water resources, less than 0.01 percent occurs
as surface waters, and is the home to a very high level of biodiversity. The multitudes of such forms have created
varying ranges of habitats that are the home to the great diversity of freshwater fauna, of which the vertebrate
fauna in freshwaters accounts for nearly 25 percent of the global vertebrate diversity, but these also happen to
be among the world’s most threatened ecosystems (Groombridge, 1992). It has been suggested that global
freshwater biodiversity is declining at far greater rates than is true for even the most affected terrestrial
ecosystems (Riccardi and Rasmussen, 1999). It is in this context that future developments in the sector have to
take into consideration aspects on biodiversity conservation.
Asia is known to be blessed with the highest amount of useable, surface freshwater resources of all continents,
but the per capita availability of the resource is the least (Nguyen and De Silva, 2006). The freshwater resources
occur in many forms, such as rivers, streams, marshes, lakes, flood plains and the like, and those from
anthropogenic interventions such as reservoirs and pools. Freshwaters utilised for fishery enhancements are
variable form country to country in the region (Table 1). It should also be noted that all the acreage is not
necessarily utilised for fishery enhancements, which provides an indication of the scope of enhancements that
is possible with a consequent increase in food fish production and provision of livelihoods.
The freshwater fish diversity of the Asian continent is high and diverse with an estimated cumulative total of
7 447 species, which accounts for approximately 25 percent of all known global finfish species (Nguyen and De
Silva, 2006). It has also been pointed out that the Asian freshwater fish species diversity is higher when compared
to other continents, but lower in familial diversity. In Asian freshwater fish fauna the dominant groups are
cyprinids (Cyprinidae, about 1 000 species), loaches (about 400 species) of the families Balitoridae and Cobitiidae,
gobids (Gobiidae, 300 species), catfishes (Bagridae, about 100 species), and the Osphronemidae (85 species).
With such a high faunal diversity, and an equally high degree of endemicity inland fishery enhancements need
to revolve around practices that do not overly impact on this diversity. Most of the countries that have
Table 1.  The varying types of freshwater resources utilised for fishery enhancements in ten countries
Country Rivers
Lakes (ha)
Reservoirs (ha)
(ha) large & medium Small
Bangladesh 24 000 km2
2 946 950 58 300
China 7 650 000 (ha) NA 7 140 000 211 000
India 29 000 (km) 354 213 720 000 1 667 809 1 485 557
Indonesia 12 000 000  (ha) 1 800 000 50 000
Myanmar 1 300 000 (ha) 8 100 000 115 687
Nepal 395 000 (ha) 5 000 1 500
Republic of Korea 2 800 km2
110 800
Sri Lanka NA 4 049 109 450 39 271
Thailand 4 100 000  (ha) 400 000
Vietnam 340 000
NA – data not available; * includes ox bow lakes, beels, haors and baors; ** includes flood-plain lakes and associated wetlands171
contributed to this synthesis have a diverse and a rich freshwater fish fauna, perhaps with the exception of
Sri Lanka, a continental island which has only 62 species recorded but of which over 25 percent is endemic to
the island. Similarly, in the Republic of Korea of 269 species and mollusks 61 species are endemic to the country.
Bangladesh on the other hand, has a fish fauna of 267 species, belonging to 156 genera and 52 families, whilst
109 species are known from the River Ganga system in India, out of a total of 765 of the whole sub-continent.
Obviously, not all of the rich fish fauna is used for fishery enhancement purposes in any of the countries. Fish
species selected for enhancement usually fall into tow major groups, species of great economic important
(e.g. carp species) and species in danger or serious depletion of population, which are of great scientific value
(e.g. Chinese sturgeon). For example, the Republic of Korea has recognized seven finfish species (Korean bullhead,
Psedobugrus fulvidrac; far eastern catfish, Silurus asotus; Japanese eel, Anguilla japonicus; Crusian carp, Carassius
auratus; mandarin fish, Siniperca scherzeri; sweet fish, Plecoglossus altivelis; common carp, Cyprinus carpio) for stock
enhancement, together with one crustacean, one mollusk and one turtle species. In general, in the region, the
main indigenous species utilized for stock enhancement purposes are the common carp, and the Chinese and
Indian major carps, supplemented by other species, case by case. In most countries in the region in addition to
indigenous species alien species are also used for enhancement purposes.
The selection of species for stock enhancement purposes varies from case to case. In most instances, especially
in enhancement food fish purposes, the choice is based on the high growth rate, feeding habit, often omnivorous
fish species being preferred, and consumer acceptability. The best examples of such species are the Chinese and
Indian major carp species. In certain instances stock enhancement may be carried out to fill a vacant niche in
a water body, such as for example the use of ice fish in China and Vietnam.
3.1 An overall perspective
The contribution of inland fisheries to the global fish supplies can be considered as small, being around 10 to
12 percent of the total capture fisheries production. However and very importantly, the bulk of the inland fishery
production occurs in Asia, the region contributing almost 70 percent to the global production (Figure 1), a trend
that has existed over the last two decades or more, being ample evidence of its significance to the region as
a whole. Also, it is evident that inland fisheries production has been rising, albeit slowly, the major impetus coming
from the Asian region. China is a major contributor to the inland fisheries production in the region, approximating
about 35 percent.
Figure 1.  The trend in inland fish production in PR China, Asia and the world and the percent
contribution of the former to the word production.
12 000
10 000
8 000
6 000
4 000
2 000
Production ( × 1 000 tonnes)
China            Asia             World            % Asia            % China of Asia172
It is often said that overall the inland fish production and hence its contribution to global food fish supplies is
underestimated, and it has been specifically demonstrated for example for the Lower Mekong Basin (LMB)
fisheries (Coates, 2002). Coates (2002) estimated that the fishery of the LMB accounts for nearly 2.5 million tonnes
per year, and pointed out the difficulties in obtaining reliable inland fish production statistics. Hortle (2007), with
reference to the Lower Mekong Basin riparian countries demonstrated that the estimates of inland fish production
of the FAO (equivalent to those reported by individual countries) are significantly lower, for some countries as
low as three fold. Hortle (2007) emphasised the need for harmonization of basic statistical data collation and
reporting. Similarly, fresh estimates based on consumption surveys in 2005 have indicated that the inland fish
production from inland waters in Thailand to be 1 062 696 tonnes (Lymer et al., 2008), almost a five fold higher
estimate than that reported by the Royal Government of Thailand estimates.
In most developing countries, and particularly in Asia, inland fishery produce are almost totally used for human
consumption, fresh and or processed into such products as sun-dried fish, fish paste, fish sauces etc. However,
there are a few exceptions, such as in the case of Mekong Delta flood plain fishery where some amounts of the
catch is used for converting into dried fish powder to be later used in the preparation of feeds for cultured stocks
(De Silva, 2008), and or fed directly as raw fish to such stocks. It is also important to note that inland fisheries in
Asia are rural and therefore benefits rural communities who generally tend to be poor.
3.2 Overview of Asian inland fishery practices
The importance, magnitude and the nature of inland fisheries in Asia are very wide ranging and diverse, much
of which are based on traditional practices. In most countries in Asia the bulk of inland fisheries for food fish
production occur in lacustrine waters, while the riverine fisheries, apart from that of the Lower Mekong Basin,
(which supports a large fishery and millions of livelihoods), have declined over the years. The more recent
developments in inland fisheries in Asia have occurred in the vastly increased acreage of reservoirs in the region
(Nguyen and De Silva, 2006), impounded for irrigation, flood protection and hydroelectricity generation and or
for multi-purposes with fisheries becoming an important secondary user of these impounded waters. In some
nations such as in Myanmar and Bangladesh, countries with very large flood-plain waters, there are organized
flood plain fisheries, referred to as leasable fisheries in Myanmar, based on naturally recruited and stocked species,
augmented by stocking.
The individual fisheries vary in intensity (Table 2, FAO, 2010), modes of operation and production within and
between countries. In most countries in Asia inland fisheries tend to be artisanal, where small motorized and or
non-motorized crafts, manned by two persons, using either gill nets or traps are the main mode of operation. On
the other hand, in large water bodies mechanised boats are used to operate purse seines, often only small
numbers (e.g. Thailand) and using integrated nets as gear (e.g. China). In countries such as Indonesia, Myanmar
and Sri Lanka use of motorized crafts in inland fishery activities is prohibited. Shore seines for example are
permitted in India but not in Sri Lanka. It is also important to reiterate, as pointed out in Section 2, the potential
gross underestimation of inland fish production in some countries, such as for example in most of the Lower
Mekong Basin riparian countries (Hortle, 2007; Lymer et al., 2009).
In most countries in Asia, the main species in inland fisheries tend to be indigenous species, at times translocated
across their natural range of distribution within the country boundaries. For example, the inland fisheries in China
are predominated by major Chinese carp species, such as silver carp (Hypophthalmichthys molitrix), bighead carp
(Hypophthalmichthys nobilis), common carp (Cyprinus carpio) etc., whereas those in India and Bangladesh are
predominated by Indian major carps, such as rohu (Labeo rohita), mrigal (Cirrhinus mrigal), catla (Catla catla) etc.
Similarly, in Thailand the inland fisheries are predominated by indigenous catfish and snakehead species, as well
in some waters by the native pelagic freshwater clupeid, the river sprat, Clupeichthys aesarnensis (Jutagate et al.,
However, in Sri Lanka, an island state with a relatively depauperate native fish fauna, the backbone of the inland
fishery, particularly those based on self-recruitment, in large reservoirs, is almost entirely predominated by exotic
tilapias. In Vietnam the inland fisheries in the past was based primarily on alien species, regularly stocked, but in173
the last decade there had been a gradual shift to a predominance of indigenous species, small cyprinids species
such as Toxobramis houdemeri, Pseudohemiculter dispar, Coulter erythropterus, Cranoglanis spp., etc.
 In essence in the large lakes and reservoirs, fisheries are based on naturally recruiting stocks, occasionally of alien
species. However, the major exception is China, where even large reservoirs and lakes (e.g., Danjiangkou and
Qinghaihu, etc.) are stocked with seed of suitable species, primarily Chinese major carps, common carp, naked
carp, etc. on a regular basis, and harvested using integrated nets.
4.1 Reasons for stock enhancement in the region
Fish stock enhancement in the region is carried out for varying purposes and reasons, and differs from country
to country. The great bulk of stock enhancement is conducted for public good to increase food fish production
and even for purposes of uplifting existing fisheries. Some stock enhancements are associated with conservation
of fish stocks, revitalising endangered fish stocks/populations as well as for mitigating environmental degradation
resulting from anthropogenic impacts.
Fish stock enhancement is also sometimes carried out to mitigate the negative environmental impacts of
intensive aquaculture activities, such as with the regular occurrence of fish kills due to poor water quality, which
in turn enables the maintenance of fish production and livelihoods and fisher communities who also happen to
be poor and most wanting (Abery et al., 2005).
Fish stock enhancement of small water bodies, often non perennial, for food fish production and provision of
livelihoods, as conducted in India, Lao PDR, Sri Lanka, Thailand and Vietnam, borders on aquaculture, as often there
is ownership of the enhanced stocks.
In addition to all of the above, is the practice, in countries such as Cambodia, Lao PDR, Myanmar and Thailand,
of “fish releases”, an indirect form of enhancement that is conducted for symbolic and cultural reasons, related
to traditional yearly water festival celebrations (i.e. water-flushing “Songkran” festival as practiced in Cambodia,
Lao PDR and Thailand). These activities have been ongoing for over five to six decades and are associated with
extensive community involvement in the festivities.
Table 2.  The inland capture fishery production (FAO, 2010) and the main sources of production
Bangladesh 1 060 181 Flood plains; rivers, reservoirs
China 2 248 347 Ponds, rivers, Lakes and reservoirs (including aquaculture)
India 953 106 Rivers, estuaries, lagoons and upland lakes (through capture fisheries); small
reservoirs and closed wetlands (through culture based fisheries);  medium and
large reservoirs, and open wetlands (through enhanced capture fisheries)
Indonesia 323 150 Lakes, reservoirs, flood plains, rivers
Myanmar 814 740 Flood plain leasable fisheries, river fisheries
Nepal 21 500 Rivers, lakes, reservoirs
Republic of Korea 5 202 Rivers, lakes and reservoirs
Sri Lanka 44 500 Open water reservoir fisheries; culture based fisheries in small water bodies
Thailand* 231 100 Riverine and reservoirs, culture-based fisheries
Vietnam 140 900 Riverine and open water reservoir fisheries; culture based fisheries in small
water bodies
* note that Lymer et al. (2009) estimated at 1 062 696 tonnes
4.2 Summary of current stock enhancement practices
Stock enhancement through seeding of water bodies has been in practice in many countries in the region for
long periods of time, for varying purposes. For example, the stocking of artificially propagated Chao Phraya giant
catfish seed (Pangasius sanitwongsei) into rivers in Thailand was conducted entirely for the purpose of
conservation of this endangered species. A summary list of species used in stock enhancement purposes and
those that are indirectly impacted upon by the various practices, for each country, is given in Annex I. It is evident
from Annex I that a wide variety species are included in stock enhancement practices in the region, and in all
probability this list of species is far from complete either.
For convenience and clarity the current stock enhancement practices in Asia are considered in the following
sections in the context of the broad water types.
4.2.1 Stock enhancement in rivers
Stock enhancement of rivers is conducted in China, India, Malaysia, Myanmar, Republic of Korea and Thailand. Such
activities are not necessarily associated with a view to increasing food fish production and or supporting
livelihoods, but primarily towards conserving and or restoring the riverine stocks, and on occasions for purposes
of environmental improvement. In general, stock enhancement of rivers is based on indigenous species, such as
for example the Indian and Chinese major carps being used to enhance the respective riverine stocks in each
of the countries, and or the use of mahseer (Tor) species in India and Malaysia. However, there is a dearth of
information on the impacts, environmentally, production wise and economically, from such enhancement
On the other hand, river stock enhancement is conducted as a compensatory measure (e.g. Thailand) when
anthropogenic impacts such as discharge of pollutants result in mass mortalities of the riverine fish. In
Bangladesh, fish aggregating devices, such as brush parks, created using bushy tree branches and twigs, locally
known as katha, are used in secondary rivers and canals, as the fish are harvested as the water recedes after six
to eight months of operation (Kibria and Ahmed, 2005). The effectiveness of use of brush parks as fish aggregating
devices in the tropics was reviewed by Welcomme (2002), and its advantages as a fishery enhancement practice,
benefiting poor communities were demonstrated.
4.2.2 Stock enhancement in flood-plains
Stock enhancement in flood-plains and associated waters as in the case of Bangladesh flood plain depressions
(e.g. termed as baors and hoars), is conducted for food fish production both in Bangladesh and Myanmar. In
Myanmar, the process is termed “leasable fisheries” where areas of the flood plain are leased out through auction
to the highest bidders. This form of a fishery has been in existence for over five decades. The lessees often
enhance the fish stocks in their leases with a view to increasing production, and accordingly the production has
increased from 91 980 in 1998-1999 to 209 720 tonnes in 2008-2009. It is also important to point out that
there had not been a significant change in the number of leasable fisheries in Myanmar, ranging from 3 280 to
3 450 since the 1990s, indicative of the regulatory aspects of permitting leasable fisheries.
In Bangladesh a similar process occurs in baors and haors of the flood plains. Baors (5 488 ha) are ox bow lakes
whereas haors (2 832 790 ha) are flooded plains between two rivers and their tributaries, and are generally
non-perennial in nature, retaining water for 4 to 6 months in the year, but highly productive, biologically. The fish
populations of these waters are enhanced through stocking, primarily of indigenous Indian major carps, and the
total yields from baors and haors in 2008 were reported to be 77 500 (679 kg/ha/yr) and 819 500 (290 kg/ha/yr)
tonnes, respectively, perhaps far exceeding the natural fish productivity should there be no enhancement. Also
in almost all instances of flood plain stock enhancements indigenous species are utilised, but there is some
appearance of exotics, for example tilapia in the case of flood plain leasable fisheries in Mandalay, Myanmar.
Both of the above fisheries also have social implications, for instance, by limiting access and alienating the
communities living in the vicinity of these waters from fishing and or obtaining fish for consumption. In175
Bangladesh this social problem is being addressed through the implementation of co-management of the fishery
resources of baors and haors where the community as a whole is able to benefit from accessing the fishery
resources (Valbo-Jørgensen and Thompson, 2007).
4.2.3 Stock enhancement in static water bodies (lakes and reservoirs)
As mentioned previously Asia has the largest reservoir acreage in the world, and the great bulk of these reservoirs
have been impounded in the second half of the last century. Fisheries are becoming very significant secondary
users of water resources in all countries, except in Myanmar where fisheries development in reservoirs is banned.
In general, in the region reservoir fisheries contribute significantly to inland food fish production and provision
of livelihoods (see Table 2).
Fish stock enhancement activities in static water bodies differ from country to country, and between water bodies.
In China for example, there is regular stock enhancement for large and medium-size reservoirs and lakes, often
with Chinese major carps, and common and crucian carp and associated fisheries which are well managed and
regulated. Some of these fisheries can be considered to be industrial scale. The other end of the scale is the
fisheries of large perennial reservoirs in Sri Lanka where the fisheries are primarily based on exotic tilapias, with
minimal stock enhancement conducted on a regular basis, the fisheries are almost entirely based on natural
recruitment. On the other hand, in Thailand although large reservoirs are stocked with exotic species such as
Chinese and Indian major carp species on a regular basis, (in accordance with a decree by the King of Thailand),
but these species account for a small amount of the reservoir fish production, which is predominated by
indigenous cyprinids, snakeheads and catfishes, and in some instances the riverine clupeid,  Clupeichthys
aesarnensis (Jutagate et al., 2003). In all of the above instances, including in other countries in Asia, e.g. Bangladesh,
India, Indonesia, Lao PDR, Vietnam fisher communities are established and operate these fisheries. However, there
is a general lack of understanding of the direct returns from stock enhancements of large static waters. Perhaps
the balance of evidence suggest that stocking of large reservoirs will have minimal impact on food fish
production except in instances where the reservoir water management and fishery management work
cooperatively, such as for example enabling complete harvesting, having devices to prevention the escape of
stocked seed, stocking of larger sized seed, provisions for use of integrated nets/appropriate gear, etc., as in China.
Perhaps one of the most notable successes of a stock enhancement activity in a natural lake in Indonesia is that
of Lake Toba, North Sumatera, Indonesia. Stock enhancement commenced in 2003, with bilih (Mystacoleucus
padangensis) at which time the total fish production of the lake was only 53.7 tonnes and reached nearly
3 036 tonnes in 2008, with an average catch of 0.5 to 2.0 tonnes/day. Interestingly, in this case the above species
was translocated from a naturally occurring population(s) of Singkarak Lake (West Sumatera), and in a manner
is comparable to the icefish (Neosalanx spp.) translocation across China and indeed introduction of the latter to
reservoirs in Vietnam.
In all of the above cases it is imperative that the success of stock enhancement will finally depend on effective
fishery management, a fact that it not adequately appreciated.
Different to the above stock enhancement practices are those conducted in smaller, often non-perennial
water reservoirs, such as in India (Sugunan, 1995; Sugunan and Sinha, 2001), Lao PDR (Saphakdy et al., 2009),
Sri Lanka (Amarasinghe and Nguyen, 2009; Kularatne et al., 2009), Thailand (Lorenzen et al., 1998) and Vietnam
(Nguyen Son et al., 2001) where the water bodies are stocked with suitable species and are harvested as the water
recedes. The fisheries are communal based, co-managed, and border on aquaculture as the stock is owned by the
community. The sustainability of such operations are ensured to a significant degree through the collection of
levies for continued stocking for the following growth cycles, as exemplified in the case of the culture-based
fishery operations in Sri Lanka.176
4.3 Other enhancement practices
In addition to stock enhancement practices in operation in the region there are many fishery related
enhancements that are in operation, in all of the above water types dealt with previously. The most important
aspects of enhancement in the above regard are summarised as follows.
(a) Provision of fish sanctuaries/protected/conservation areas:
The above is practiced in natural water bodies in most countries, for example in the flood plains of
Bangladesh. The establishment of sanctuaries is decided on technical advice of the authorities in
cooperation with the community, and agreed sanctuary size could range from 1 to few hectares, the
area designated being clearly demarcated by some form of fencing. The habitats in the demarcated
areas are further enhanced by adding substrates etc. In the Republic of Korea there are 19 (15 lakes
and 4 streams; total of 330 km2
) designated as protected areas, amounting to 6 percent of the
country’s inland waters. Similarly, 605 protected areas exist in India in the form of National Parks, Wildlife
Sanctuaries and Conservation Reserves, covering approximately 4.74 percent of the total geographical
area of the country.
In all of the above, fishing is strictly prohibited and such regulations are strictly enforced.
(b) Provision/improvement to spawning habitats:
In some countries in the region, e.g. China there is an ongoing program to provide and or improve
spawning habitats, in particular for non-migratory species, such as common carp and crucian carp.
(c) Habitat improvements:
Habitat improvement is conducted in respect of many fisheries. Improvements are related to
augmenting the nature of spawning grounds of specific species, particularly in larger water bodies. In
flood plain fisheries introduction/modification of habitats to enhance refuges for naturally recruited
young is often undertaken by the provision of structures such as brush piles. Brush piles are also utilised
in culture based fisheries, as they have been shown (also see Section 5.2.1.) to enhance periphyton
growth and are thought to provide an additional food sources for most omnivorous fish (Azim et al.,
Other enhancements include weed removal and desiltation, which are commonly undertaken in
Thailand for instance.
(d) Introduction of closed seasons:
Most countries have introduced closed seasons for stock enhancement purposes mostly in water
bodies that have established fisheries. Such closed seasons are related to the knowledge on the
reproductive seasonality of the predominant species of the respective fisheries, such as for example
in inland waters in Thailand (dates: 16-05 to 15-09, country-wide), where the fisheries are mostly
dependent on indigenous species. The above period coincides with the onset of rains when the
predominant group of fishes, mainly cyprinids, tend to breed. However, even in this period, fishing for
household consumption is permitted.
In the Republic of Korea the operation of closed seasons are even more regulated, with specific time
periods being applied for each of the target species. For example, for salmon, Oncorhynchus keta,
mandarin fish, Siniperca schezeri and sweet fish,  Plecoglossus altivelis the closed seasons are 01-10 to
30-11, 20-05 to 30-06, and 01 to 31-05 and 01-09 to 31-10, respectively. Closed seasons, when operating,
are generally strictly enforced by the authorities.
(e) Gear restrictions:
In most inland fishery operations gear restrictions apply, and are fairly strictly enforced. In Sri Lanka and
Thailand for example, seine nets are prohibited in most large reservoir and lake fisheries, whilst it is177
permitted in India. In general, seine nets are used in harvesting in culture based fisheries. In China, in
most medium and large-sized water bodies the main gear used is an combined fishing method using
blocking net, driving net, gill net and set bag-net simultaneously in one fishing operation, which
ensures the capture of a significant proportion of stocked fish of specific size range, in a few operations.
4.4 Key issues related to stock enhancement of inland waters
4.4.1 Size of seed for releasing and stocking
In the region, in general, the size of released/stocked seed in those practices on which fisheries are based take
care to ensure that it is optimal for stocking. However, strict guidelines in this regard are not readily available in
most countries. In China for example strict guidelines are adhered to on the size of seed for stocking, often around
15 cm in body length. On the other hand, those enhancements that are conducted for symbolic and cultural
purposes often tend to use undersized seed stock, the returns from such practices for building up natural
populations is likely to be insignificant.
4.4.2 Seed quality
In all instances there is very little attention paid to the quality of seed stock used, and their genetic compatibility
with that of the natural stocks, an aspect that warrants attention. In general there is very limited or no evaluation
of the hygiene of the seed stock and risk assessments. These are imperatives if improvements are to be brought
to stock enhancement practices in the region, which would help minimise negative impacts.
The general notion is that stock enhancement of indigenous species may not be genetically harmful to the
natural populations has been shown to be incorrect as shown by many studies in the northern hemisphere in
respect of salmonoids in particular. Bearing in mind that seed required for stock enhancement purposes have to
be from hatchery produced stocks, which are known to be of lower quality than its wild counterparts, the most
pragmatic option would be to secure proper broodstock management plans and closely associate the
enhancements to remain compatible with the genetic diversity of specific wild populations of the species.
Needless to mention that introduction of such programs have a cost, require high technical skills, and therefore
will need a rationalised approach in the selection of species and the extent of adherence to designed
management plans. This aspect is dealt in further detail in Section 6.4.
4.4.3 Socio-economic aspects
There is no doubt that adoption of stock enhancement procedures that have led to establishment of fisheries
have had a socio-economic impact by providing livelihood opportunities, and in all probability an improvement
in the nutrition of rural populations by making available affordable food fish supplies. On the other hand, as
pointed out in Section 3.2.2 lease of waters such as in Bangladesh and Myanmar would limit the access to these
resources by the poor. It is encouraging to note that the above is being addressed to some degree in Bangladesh
by reverting to a co-management of the resources, leading to a sharing of the benefits (Valbo-Jørgensen and
Thompson, 2007).
The most detailed socio-economic gains of stock enhancement are evident in the case of culture based fishery
activities in many countries; best exemplified by the example from India, Lao PDR (Garaway et al., 2006; Saphakdy,
2009), Sri Lanka (Amarasinghe and Nguyen, 2009; Kularatne et al., 2009) and Thailand (Garaway et al., 2001).
Experience in Vietnam (Nguyen Son  et al.,  2001) showed that leasing of waters, for culture based fisheries,
on a short-term basis may not be most appropriate as the lessees are discouraged from bringing about
improvements to physical attributes of the water body that could enhance fish production. Medium to long-term
leases may encourage more responsible management, provided it is associated with regular monitoring by
The involvement of the private sector for management, including stock enhancement and associated aspects of
water bodies for fisheries development as evident in the case of Vietnam, is a new initiative in the region as178
a whole. This initiative, which is to be extended to new major impoundments, is likely to have socio-economic
impacts on the communities living in the vicinity, as well as fisher livelihoods prior to impounding, through
marginalization of the latter. Close monitoring of this will be of use to the region as a whole in making suitable
policy decisions in this regard.
4.4.4 Governance issues
Admittedly the governance issues are rather complex and vary widely between countries. One common
denominator in this regard, however, is that almost all water bodies used for food fish production and
conservation purposes come under the purview of many governmental agencies, often operating under different
ministries. Overall, in the region, reservoir fisheries are a secondary activity and the water management of the
impoundments come under the purview of different authorities, such as for example in Thailand under the
Electricity Generating Authority of Thailand (EGAT), Irrigation Department in most cases in Sri Lanka, under the
Forestry Department in Myanmar and so forth.
A better dialogue with the water management authorities and fishery authorities is likely to bring about improved
impacts on fish production, without necessarily impacting negatively on the primary user purposes. However,
there is increasing evidence to believe that with the creation of new impoundments there is a realization that
the secondary use of the waters for food fish production and livelihood generation could be of significant value,
both socially and economically. In this respect the best examples could be drawn from Indonesia (Citarum water
shed reservoirs; see Abery et al., 2005) and Nepal (Kulekhani reservoir; see Gurung et al., 2009) where cage culture
activities for displaced communities were accepted and supported as an alternate means of livelihoods, and more
importantly there activities have been sustained for more than 20 years, with a concurrent development of
a capture fishery, which is enhanced through a variety of measures.
Adoption of fishery enhancement practices has also resulted in relevant changes in governance that have
facilitated the development of such activities. For example, in Sri Lanka non-perennial reservoirs were not
permitted to be used for fishery enhancement under the Agrarian laws that were prevalent. However, the law was
amended to permit fishery enhancement through culture based fisheries development and this change has
further facilitated these developments (Amarasinghe and Nguyen, 2009). In Indonesia, with the stock
enhancement of reservoirs in the Citarum watershed with milkfish, for mitigating purposes, were accompanied
by the introduction of mesh size restrictions by the District Governing authorities, in concurrence with the fisher
communities, which enabled the establishment of the activity and a further step towards the sustainability of the
The successful introduction of the tagal system (see Section 5.4.f), a partnership between communities and the
government, for protecting, rehabilitating, conserving and managing fishery resources in the state is a good
example of a management system involving aboriginal communities. Each community must have traditional user
rights, to be eligible to participate in this partnership, preferably rights to several deep pools in the river and
manage and use its fishery resources under the leadership of the headman of the community (Wong, 2006).
By 2006, the ‘Tagal’ system of management had been set up at 234 sites in 11 districts involving 124 rivers and,
consequently, had successfully revived the depleted river fish populations, including many with mahseer (Wong
2006). A similar approach has been reported from Corbett Park in India, in which the ‘Conserving the ‘‘tiger fish’’
(i.e. mahseer)’ project aims to tap the potential of ecotourism in the buffer area of Corbett National Park. Guided
by enhancement of the prospects for tourism, residents from several villages have been working to conserve
mahseer in the River Ramganga and in other streams in the region. Locals have been taught about the
importance of conserving the mahseer species, thus leading to increases in population size of mahseer
(Anonymous 2008).
4.5 Investments/Returns from stock enhancements
The investment to fish stock enhancement in the region has been increasing significantly recently. For instance,
the budget allocation by the central government for implementing enhancement activities in major river systems
in China has been maintained around UDS26 million annually in recently years. In general, investment for179
enhancement program for public goods, particularly releasing program in major river systems and large lakes is
usually borne by the central government (China, Republic of Korea and Thailand). The seed releasing and other
enhancement activities in water bodies (such as medium and small-size lakes and reservoirs) with well managed
fisheries are often multi-source funded, which include mainly budget allocation from local government and
contribution from direct beneficiaries (fishers). One common practice for the later is payment of resource
enhancement fee at renewal of fishing license. It is worth to notice that there has been steady increase of public
donation for stock enhancement in some countries with the increasing public awareness of importance to protect
the aquatic biodiversity and ecosystem.
Overall and in general terms the investment related return from stock enhancement is little known, except from
the smaller water bodies as in the case of Thailand and Sri Lanka, where the total production is essentially from
stocked seed and the other inputs are quantified (Amarasinghe and Nguyen, 2009; Kularatne et al., 2009). Without
regular stock enhancement of many flood plain water bodies, large reservoirs, where the natural recruitment is
relatively poor, fisheries would likely not have developed. In most countries the cost of stock enhancement,
particularly those associated with conservation purposes, is often borne by government agencies, central and or
regional. In Thailand for example there are stock enhancements that are conducted under a decree of the Queen.
In other enhancements, for example for CBF, mitigating environmental impacts such as in Indonesia, the
government and or other agencies may kick start the fishery development, but as the activity progresses the
community benefiting from it will begin to bear the costs of enhancements.
There is also a trend, such as in Vietnam where the cost of all stock enhancements and the associated fishery
benefits are handed over to the private sector, almost akin to a lease. The enhancement of the high valued giant
freshwater prawn, Macrobrachium rosenbergii, in Pak Mun Reservoir (a run-of-the river type dam), Thailand,
provides a useful case study on investment-returns of stock enhancement as well as the use of the process for
a conflict resolution where the closure of the dam impacted negatively on the livelihoods of the river fishers. In
this instance although the recapture rates were less than 2 percent, giant freshwater prawn accounted for
54 percent of the total catch and 97 percent of the total income of the fish landings (Sripatrprasite and Lin, 2003).
The cost of stocking, however, is borne by the government as an indirect compensation measure.
In a comparable case in Indonesia, in the reservoirs of the Citarum watershed (Jatiluhur, Cirata and Saguling)
where cage culture, proliferated and intensified and impacted negatively on the water quality, resulting in fish
kills that adversely affected fishers. In this instance stock enhancement, primarily milkfish, Chanos chanos, and
the introduction of an associated co-management practice, involving all stakeholder groups, has resulted
in improvements in water quality, and negated potential conflicts (Abery  et al., 2005) between fishers and
fish farmers. Most of all the practice has increased the income of fishers, whose payment of a nominal levy of
IDR 600/kg (IDR 9 300 = 1 US$) on the landings of the stocked species has also sustained the stock enhancement
program, which was initially borne by the government. It is also believed that the use of milkfish, which is unlikely
to establish reproductive populations in the reservoirs and the associated river system, would be ecologically less
impacting than the use of other filter feeding fish species.
It is also important to note the socio-economic success of enhancement of translocations of species such as
bilih into lake Toba, Indonesia, which has stimulated the consolidation and a significant enhancement of the
fishery (three fold), generating extra livelihoods, and enabling higher fisher earnings, reaching a maximum of
320 000 IDR/fisher/day.
4.6 Monitoring and impact assessment to releasing and other conservation program
Fish seed releasing and other stock enhancement activities have been extensively carried out in the region and
for decades in some countries. There has been general lack of effective monitoring and impacts assessment to
various enhancement and conservation activities such as seed releasing, protected area and sanctuary etc. except
for limited assessment studies conducted for releasing program implemented for few species, such as Chinese
sturgeon and salmonoids. Most stock enhancement programs have been carried out without considering
follow-up monitoring to assess the effectiveness and impacts.180
Lack of effective monitoring and impact assessment is mainly due to technical difficulty and resource limitation.
Currently, there is still lacking of effective and economical methods and tools for monitoring and assessing impact
of large scale releasing activities in the region. On the other hand, almost no financial resource is allocated for
monitoring and impact assessment activities even though huge budget is allocated to releasing of fish seed. The
reluctance of government in allocating fund for monitoring and impact assessment is often due to difficulty in
monitoring the use of the fund and long time-span of the work. In addition, monitoring and impact assessment
are not so eye-catching compared with the releasing activities which usually easily attract public attention.
Obviously, it is not possible to understand the actual effect of seed releasing and other stock enhancement
activities without reasonable monitoring activities. Therefore, the actual impacts of most stock enhancement
activities in large open water bodies in the region have remained questionable although it has been believed
significant ecological and socio-economic benefits achieved. More importantly, it is difficult to make informed
decision on improving the methodologies, operation and follow-up management to achieve better results with
limited resources.
4.7 Issues related to marketing
The general notion is that all of the inland fish production is used directly or in a processed form for human
consumption, which contrasts to that of the marine production where nearly 25 to 30 percent is used for
reduction into fish meal and fish oil (Delgado et al., 2003). However, it has been pointed out in Section 2 most
such inland fish production is used for aquaculture purposes directly or indirectly. In general the marketing
aspects, though important, have taken a backstage (De Silva, 2008).
With increasing potential in culture-based-fisheries, and its increasing adoption in the region with developments
in India, Indonesia, Thailand, Sri Lanka and Vietnam, where the harvesting is essentially dictated by the weatherreceding water levels-there is a need to address this aspect, to avoid an excess supply (within a narrow time frame,
in a small geographic area). In this regard some countries have adopted a staggered harvesting strategy, thereby
ensuring a wider spread of the time frame and a reasonable farm gate price. In Myanmar the involvement of
women in marketing of culture-based-fishery produce in some instances (FAO-NACA, 2003) have brought about
an added dimension of livelihood supportfor the poorer sectors but this needs to be further encouraged.
On the other hand, in large water bodies the marketing chains are relatively well established, with middle persons
playing a vital role (De Silva, 2008). In China, where a single days harvest, by the use of integrated nets, could be
very large. Fish may be kept in pens within the water body and marketed in small quantities over a few days,
thereby ensuring a fair farm gate price and avoiding an oversupply. In Vietnam most middle persons operate in
boats when a group of fishers would sell their fish to same middle person, at times on a barter basis, the former
then in turn markets through wholesale buyers on shore.
5.1 Physical and management measures
Inland fisheries enhancements and biodiversity conservation in most countries in the region are intrinsically
linked. As pointed out in Section 5.3 there are direct steps taken towards biodiversity conservation by creation
of fish sanctuaries and refuges, introduction of closed seasons, complete prohibition of fishing operations in
selected waters and so forth. Whilst such ‘physical and management’ measures are widely adopted one of the
main concerns with regard to biodiversity conservation is the introduction of alien species and trans-boundary
movement of indigenous species across their natural range of distribution for stock enhancement purposes.
5.2 Retaining connectivity among waters
The inland waterways have been greatly impacted through interference from anthropogenic activities, primarily
for irrigation purposes, by impeding connectivity. Although large dams attract attention of conservationists, the
numerous weirs, sluices and even roads and other similar man made structures impede free movement of fish,181
and consequently impact on biodiversity, both directly and indirectly. Admittedly however, the quantitative
information available in this regard on the region’s waterways is rather meagre.
One of the most advocated mitigating measures is the construction of fish passages and or fish ladders, which
some suggest has proven to be a viable option in the northern hemisphere, particularly in respect of facilitating
salmonid migrations. On the other hand, in the region there are only a few structures, of various forms, in
operation. For instance in the Pak Mun Dam, Thailand, the available information suggests that it is not significantly
effective in facilitating upstream migrations. In addition, a number of fish passes are in operation in Bangladesh;
e.g. Sariakandi fishpass (92.4 m long and 15 m wide) on the west bank of Jamuna river and the east bank of
Bangali river (at Sariakandi upazilla sub-district) permitting fish movement between the Jamuna and Bangali
rivers. In Bangladesh all fish passes come under a management authority headed by the Bangladesh Water
Development Board.
5.3 Introduction of alien species and indigenous species translocations
Introduction of alien species is a global ‘bone of contention’, and especially so as it is often alleged that such
introductions are a main cause of loss of biodiversity (e.g. Moyle and Leidy, 1992; IUCN, 2000), even though and
more often than not, there is a lack of explicit scientific evidence in this regard. Admittedly, the relevant issues
with regard to aquaculture globally, and regionally arebetter known (see recent review by De Silva et al., 2009)
including the controversial introduction into the region of tilapias for aquaculture (De Silva et al., 2004).
Amongst alien species use of tilapias in stock enhancement purposes perhaps can be considered as one of the
most significant examples in the region. In Sri Lanka introduction of Oreochromis mossambicus in 1952 is
considered to have triggered the development of an inland fishery in the vast acreage of perennial reservoirs,
ancient and modern. There were later stock enhancements with the Nile tilapia, Oreochromis nitloticus. Currently,
these species collectively account for over 70 percent of inland food fish production, which also provides many
fisher livelihoods in rural areas (Amarasinghe and De Silva, 1999; Amarasinghe and Weerakoon 2009). Tilapias
continue to contribute to reservoir fishery production in Lao PDR, India, Indonesia, the Philippines and Thailand.
However, apart from occasional stock enhancement with a view to building up reproductive populations, there
is no regular activity in this regard, and the fisheries sustain themselves through self recruiting populations. All
evidence indicates that this introduction in the region, though the species were brought in for aquaculture
development, have not had apparent negative impacts on biodiversity (De Silva et al., 2004).
In addition Chinese and Indian major carps have been extensively translocated regionally for stock enhancement
purposes, and provide major contributions to culture-based fisheries, flood plain fisheries, lease fisheries and the
like in most countries in the region. In some instances escapees from aquaculture practices have resulted in the
establishment of relatively large fisheries, a case in point being the Gobhindasagar Reservoir, India (Sugunan,
1995), where silver carp is the predominant species of the fishery, and has also resulted in an overall increase in
production and number of fishers.
Interestingly ice fish, Neosalanx spp., endemic to Taihu Lake, China, has been extensively translocated in to other
reservoirs in China (Liu et al., 2009). However, these translocations have resulted in mixed results with populations
fluctuating over the years, and the fisheries not being consistent. More recently, ice fish has been transplanted
into a large reservoir, Thac Ba Reservoir, in Northern Vietnam. There is evidence emerging that a relatively
significant fishery has commenced four to five years after the transplantation (see Country Review on Vietnam).
More importantly, for example there were no risk assessment studies undertaken with regard to the above
translocations and also there is no evidence of monitoring of biodiversity impacts either. Bearing in mind that
this group of fish are zooplankton feeders the potential for biodiversity conservation impacts remain likely.
Comparable to the trans-boundary translocation of ice fish in China, beyond its natural range of distribution, is
the example of translocation of bilih (Mystacoleucus padangensis) into Lake Toba, North Sumatera, from Sinkarak
Lake (West Sumatera) in Indonesia (see Section 5.2.3 for further details). Although this translocation has resulted
in positive impacts on the fishery and related livelihoods, and the socio-economic status of the fishing
communities, its impacts on biodiversity conservation are yet unknown.182
5.4 Genetic aspects related to stock enhancement practices
The common notion, at least until recently, was that use of indigenous species in stock enhancement practices
impact on biodiversity to a lesser extent than alien species. The use of modern genetic tools in population studies
have shown that unplanned stock enhancement practices based on indigenous species could lead to negative
biodiversity impacts and loss of genetic diversity of the natural stocks. Such detrimental impacts have been clearly
demonstrated for northern hemisphere salmonid strains/species e.g., Dowling and Childs, 1992; Leary et al., 1993;
Allendorf and Leary, 1998).
In Asia the above aspects are not well documented and or known and had been relatively less studied. It has been
demonstrated that in Thailand stock enhancement of the Thai silver barb, Barbonymus (=  Puntius)  gonionotus
has resulted in the loss of genetic diversity of the wild stocks (Kamonrat, 1996). Also, it has been acknowledged
that the escapees from aquaculture practices have led to a reduction in genetic diversity of Thai catfish, Clarias
macrocephalus wild populations (Senanan et al., 2004).
As pointed out in Section 5.1 traditional stock enhancement practices conducted for cultural and symbolic
purposes in some countries in the region do not pay much heed to genetic aspects, and it is possible that
juveniles produced from one hatchery and broodstock derived from a single population are utilised along long
distances of a river or unconnected water ways. It is suggested that as the science is better known that such
practices may be suitably modified to ensure that genetic aspects are taken into account to reduce impacts on
biodiversity in the long term.
The use of milkfish for stock enhancement and mitigation of the negative impacts on water quality in reservoirs
of the Citarum watershed is an interesting example, where the assumption is made that as this species is unlikely
to establish breeding population in the reservoirs thus having minimal impact on biodiversity. This presumption
may not necessarily be always correct as indirect genetic impacts are known to occur as a result of such an
introductions (Waples, 1994).
Overall, it is evident that there is a need to step up monitoring on genetic impacts of stock enhancement
practices in the region, and where relevant begin to introduce the use of genetic tools that are available to make
enhancement practices more science based.
 In the region overall, enhancement of inland fisheries has resulted in an increasein food fish availability,
providing additional livelihood opportunities to rural poor, and contributing to socio-economic well
 However, not all enhancements in the region are socially equitable, particularly with regard to flood
plain and reservoir leasable fisheries and the like. Such enhancement protocols although bringing
about an increase in food fish production could marginalise other users in gaining access to a potential
food source and a subsidiary income opportunity. Interestingly, this fact is being addressed by some
countries, such as Bangladesh, where the leases are provided to communities rather than individuals,
and consequently benefits are shared by the community.
 In general, culture based fisheries, in smaller, often non-perennial water bodies, is a major form of
enhancement and in most instances whole communities tend to benefit and it is becoming
increasingly popular as a means of increasing food fish production and provision of subsidiary income
to rural communities.
 Enhancement of large and medium sized reservoirs is only successful if the stocks become established
and start to breed/recruit, perhaps with the exception of China where this aspect is built into the overall
reservoir management planning. Successful enhancement in such waters is therefore also reliant on
effective fishery management.183
 To further facilitate the benefits of fisheries enhancement activities, there is a need to rationalise the
water management regimes, which often tend to be beyond the purview of fishery authorities.
 The statistical data collation and reporting on inland fisheries is open for significant improvement.
There is evidence that inland fisheries production is often under estimated and there is a need to
rationalise the different methods utilised in production estimation. Equally, there is a need to step up
the socio-economic gains and losses from inland fishery enhancements, on a much wider scale than
at present. Proper data on the status of the fisheries and the human resources involved in such activities
will facilitate the improved recognition of the sector as a significant food security, nutrition and poverty
alleviation activity for rural communities, in developing countries.
 Overall, there is a paucity of monitoring of impacts of enhancements, from social, environmental and
economic view points, and there is an urgent need for authorities to introduce monitoring measures
for all types of water bodies.
 The region’s approach to biodiversity conservation  related to fisheries enhancements are significant,
with the introduction of sanctuaries, closed seasons, gear restrictions, habitat improvements, seed
releasing programs and so forth.
 The stock enhancement activities in the region sometimes use alien species and translocation of
indigenous species across watersheds, beyond the ranges of natural distribution. Although explicit
evidence is lacking with regard to impacts on biodiversity in relation to such enhancements regular
monitoring and evaluations of these would be desirable to introduce any mitigating measures where
 On the other hand, stock enhancement activities have paid little attention to potential genetic impacts
and there is a need to address these issues sooner rather than later.
 The ecosystem approach to inland fisheries needs to go beyond the scope of the water body per se,
as the production of most inland waters are highly impacted upon by the catchment features and its
activities. Accordingly, more holistic approaches to inland water resources enhancements and
management are needed.
 A concerted effort needs to be made to impress upon governments and responsible authorities of the
increasing importance of inland fisheries resource enhancement as a means of contributing to food
fish supplies and food security of rural communities in addition to protection of aquatic biodiversity
and also encourage more cooperation between fishery and water management authorities to reap the
full benefits. In this context attempts should be made to increase the visibility of the sector, through
for instance the Committee on Fisheries of the FAO.
 In the region as a whole, there is very little emphasis on pre-and post-impact assessments of fishery
resource enhancement practices, primarily as consequence of the lack of an accepted protocol for this
purpose and limited capacity available to undertake such activities. Accordingly, there is need to
develop guidelines/protocols for inland fishery enhancements for the different water body types, and
build capacity on impact assessment/monitoring of fishery enhancements in the region as required.
 In the region though a majority of fishery resource enhancements has been beneficial, socioeconomically, there is very limited monitoring of the costs vs. benefits of major, specific practices.
Monitoring of cost benefits of enhancements will provide much needed information and an impetus
to furthering the activities and bringing about improvements thereof.
 The region has a number of institutions that are directly and or indirectly involved in enhancement
related activities/programs. Equally, the capabilities in this regard differ markedly between countries,
and there is lot to be learned from each other to place fishery enhancements in the region on a firmer184
footing. In this regard the establishment of a mechanism for networking/continuing interaction for
sharing of experience on enhancement and conservation of inland fisheries resources would be most
beneficial to the all countries and to the sector’s improvement and consolidation.
 All attempts should be made to ensure minimizing potential impacts on biodiversity conservation
arising from inland fishery resource enhancements. In this regard more attention needs to be paid to
maintaining genetic diversity of wild stocks/populations, and programs need to be introduced to
incorporate scientific knowledge into enhancement practices, even those that have been conducted
over long periods for cultural and symbolic purposes. Strategic environmental assessment (SEA) is the
process for assessing, at the earliest possible stage, the environmental impacts of decisions made from
the policy level downwards. SEA is a promising means to strengthen awareness of biodiversity
conservation issues in the context of national priorities in terms of social and economic development.
 Regular monitoring needs to be undertaken on the impacts of alien species and translocation of
indigenous species across watersheds for stock enhancement practices. New such translocations should
be undertaken only after a detailed risk assessment and when and if absolutely necessary.
 Over the last two decades there has been an emphasis on aquaculture education, particularly tertiary,
in the region, for good reason. However, this impetus has not been carried on with regard to inland
fisheries in many countries, leaving a gap in the knowledge of personnel that are called upon to
manage the latter. Accordingly, there is a need to raise awareness in tertiary and vocational institutions
on the need to introduce curricula and step up training provided in inland fisheries management.185
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Annex I.  Species used directly in stock enhancement practices and those that are directly and or indirectly
impacted through inland fisheries enhancement programs/activities (in at least 2 countries)
Species Bgd China India Indo Myn Nepel RoK SL Th Vn
Anabas testudineu + + +  +
Anguilla japonicus + +
Hypophthalmichtys nobilis +* + +* +* +* +* +* +*
Barbonymus gonionotus + +*  +
Clarias gariepinus + +
Carassius auratus +* + + +* +* + +*
Catla catla + + + + +* +* +*
Chana striata + +  +
Chitala chitala + +
Cirrhinus mrigala + + + + +* +* +*
Ctenopharyndogon idellus +*  +  +* +* +* +*  +* +* +*
Cyprinus carpio +* + +* +* +* +* + +* +* +*
Eriocheir sinensis + +
Heteropneustes fossilis + + +
Hypophthalmichtys molitrix +*  +  +* +* +* +*  +* +* +*
L. rohita + + + + +* +* +*
Leptobarbus hoevenii + +
Macrobrachium rosenbergii + + + +  + +
Mastacembelus armatus + + +
Morulius chrysophekadion +* +
Mylopharyngodon piceus + +
Neosalanx spp. +** +*
Oncorhynchus mykiss
+ +
Oreochromis mossambicus
+ + + +  + +
O. niloticus
+ + + + + + + +
Osteochilus hasselti + +
Pangasianodon hypopthalmus +* + +
Probarbus jullieni +* +
Salmo gairdneri
+ +  + +
S. salar
+ +
S. trutta
+ +  + +
S. richardsonii
+ +
Tor douroensis + +
T. putitora + +
T. Tor + + +
Trichogaster pectoralis +* +* +
Trionyx sinensis + +
 alien to the region; * alien to the country; ** translocated across water sheds with in a country for stock enhancement
Bgd = Bangladesh; Indo = Indonesia; Myn = Myanmar; RoK = Republic of Korea; SL = Sri Lanka; Th = Thailand; Vn = Vietnam189
Annex II. Species used directly in stock enhancement practices and those that are directly and or indirectly
impacted through inland fisheries enhancement programs/activities in individual country
Country Species
China Acipenser dabryanus,  A. sinensis, C. asiatica, C. maculate, Chinese sucker, Coreius heterodon,
Culter alburnus, Hemisalanx prognathus, Leiocassis longirostris, Megalobrama amblycephala,
Parabramis pekinensis, Pelteobagrus fulvidraco, P. vachelli, Plagiognathops microlepis,
S. prenanti, Silurus meridionales, Sinilabeo rendahli, Siniperca chuatsi, Spinibarbus sinensis,
Squaliobarbus curriculus, Xenocypris davidi, X. microlepis
India T.  khudree
Indonesia Balantiocheilos melanopterus, Botia macracanthus, Chanos chanos, Helostoma teminkki,
Mystus nemurus, Orchella brevirostris, Osphoronemus gouramy, Sclerophages formosus,
S. yardinii, T. trichopterus, Mystacoleucus padangensis**
Myanmar C. labiosa, Ompok paba, Osteobrama belangeri, Tenualosa ilisha, Wallago attu,
Colisa fasciata*, Glossogobius sp.*, P. lala*, Parambassis sp.*
Nepal Barilius spp., Schizothorax plagiostomus, Schizothaichthys progastus, S. annandaeli
Republic of Korea Coreoperca herzi, E. japonicus, Plecoglossus altivelis, Psedobugrus fulvidrac, S. asotus,
S. schezeri
Sri Lanka Labeo dussumieri
Thailand B. schwanenfeldi, B. schwanenfeldii, C. macrocephalus, Clarias macrocephalus,
Hemibagrus nemurus, Henicorhynchus siamensis, P. sanitwongsei, Systomus orphoides
Vietnam Acipenser schrenckii*, Barbodes altus, Barbonymus altus, C. micropeltis, H. guttatus,
P. larnaudii, P. bocourti, Prochidolus lineatus
* alien to the country
** translocated across water sheds with in a country for stock enhancement purposesASIA-PACIFIC FISHERY COMMISSION
FAO Regional Office for Asia and the Pacific
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