Download - Status of Reservoir Fisheries in Five Asian Countries

8/11/2019 Status of Reservoir Fisheries in Five Asian Countries

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Status of Reservoir Fisheries

in Five Asian Countries

China - India - Nepal - Sri Lanka - Thailand


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Edited by Sena S. De Silva and Upali S. Amarasinghe

Contributors

Miao WeiminFreshwater Fisheries Research Centre, P.R. China

Jiashou Liu, Zhongjie Li and Songguang Xie

Institute of Hydrobiology, P.R. China

K.K. VassCentral Inland Fisheries Research Institute, India

V V S g nan

Status of Reservoir in Five Asian C


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NACA MONOGRAPH SERIESNACA is an intergovernmental organisation that promotesdevelopment through sustainable aquaculture. NACA seekrural income, increase food production and diversify farmThe ultimate beneficiaries of NACA activities are farmers

communities.

Visit NACA online at www.enaca.org for hundreds of freepublications on aquaculture and aquatic resource manage


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Foreword

The Icelandic International Development Agency (ICEIDA)partners in the project Strategy for Asian Reservoir FishManagement since 2006, when a Memorandum of Under

Historically, fisheries is an important element in the founeconomy, and the rich fishing grounds in Icelandic waters

platform that enabled the nation to move from poverty tcentury. This is also reflected in the focus in bilateral coo

After substantial growth in capture fisheries after the Secrate of growth was significantly reduced in the 70s and inpast three decades or so, world capture fisheries have flumillion tons annually, in spite of increased fishing pressur

environmental changes now threaten a large number of fia crisis of global proportions which calls for a move towafisheries and better utilisation of the catch. It is clear hoincreased global demand for fish has become and will conon an increase in aquaculture and fish farming. To meet tglobal investments need to be made in research and deve

Iceland and Sri Lanka launched bilateral development coothe joint aim of positive developments in the Sri Lankaspartnership initially focused on aspects of quality and mafisheries, but realising the importance of freshwater fish the abundance of inland waters suitable for aquaculture,would be welcomed when opportunities arise.

The dialogue on ICEIDA support to aquaculture developmeregion started between the ICEIDA Country Office in Sri L2006, with positive support from ICEIDAs bilateral partnesoon focused on the possible involvement and financial sua regional project, developed by NACA, addressing reservmanagement in the NACA member states The frame ork


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Contents

Foreword .........................................................

Introduction .....................................................

Development of Reservoir Fisheries in China ............

Achievements, Challenges and Strategies for ReservoirDevelopment in China .........................................

Status of Reservoir Fisheries in India ......................

Reservoir Fisheries in Nepal .................................

Present Status and Future Strategies for the ManagemeReservoir Fisheries in Sri Lanka .............................

Reservoir Fisheries of Thailand .............................


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Introduction

Reservoirs are rarely and or never created for fishery pursecondary use of the impounded waters for fisheries is beimportant activity, particularly in Asia, the region that is highest reservoir acreage amongst all continents. Reservoalso gradually becoming a significant contributor to totaloften provides a relatively affordable source of fresh and

protein source to many rural communities, as well many directly and indirectly.

Reservoir fishery activities in the recent past are also seeproviding alternate livelihood opportunities to people thaimpoundment. Such livelihoods could entail engagement or aquaculture activities such as cage culture. In addition

to take note of the vast reservoir resources that are of a the Asian region for development of culture based fisherilow cost community activity, is thought to provide significto downstream farmers and contribute to their nutrition.

Notably in the region the reservoir fish fauna, fisheries prmanagement methods, amongst others factors, differ wid

in fish yield between reservoirs and/or between countrieunderstood and are unlikely to be determined by individuor characteristics such as the reservoir fish fauna, water hydrological regimes, morphometry, management patternHowever, it is possible that there is a great deal to be leapractices of each country. In the above context and in vieimportance of reservoir fisheries in the region it was cons

take stock of the current status thereof, with a view to uto develop and or evolve appropriate national and or regsustained development of reservoirs fisheries.

This volume attempts to fulfil the above objective, and astep brings together re ie s of the c rrent stat s of rese


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Development of Reservoir Fisher

Miao WeiminFreshwater Fisheries Research Centre, Chinese Academy

214081, P.R. China.

Introduction

China has a long history of reservoir fisheries activities. Tactivity of fish seed collected from rivers took place in Dowhich was impounded some 1000 years ago in Zhejiang pMany reservoirs have been constructed in China since thepurposes and are also used as important resources for fisPresently, reservoir fisheries have become an important c

fisheries industry in China, and make a substantial contrisupplies and rural livelihoods.

China is currently in a new development stage. Environmwise use of resources are of major concern in developmegreat potential for reservoir fisheries development in Chiexist.

Reservoir resources

Nature of reservoirs

Reservoirs were constructed by the ancient Chinese, mai

regulating rain water for crop irrigation. The earliest reseQian Hu, was constructed about 1000 years ago in Zhejianthere were only about 20 reservoirs in the whole of ChinaPeoples Republic of China was founded. Since the 1950s,of different sizes have been built in China for the purposirrigation and h dropo er generation


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of Statistics, 2007) and a total storagecapacity of 562.38 billion cubic metres

(Ministry of Agriculture, 2006). Therehas been a considerable increase inthe number and storage capacity ofreservoirs in China during the past 10years, particularly of the large andmedium sized reservoirs. Reservoirscompose a very important part of

inland water resources (about 13%of inland water resources; Figure 1)in China. Lakes and ponds also formabout 56% of inland water resources.

In addition to the classification basedon geographical character, Chinese

reservoirs are also classified into threecategories according to their storagecapacity, i.e., large, medium andsmall. Numerically, small reservoirsdominate the total reservoir resourcesin the country, but the highest storagecapacity is registered for large reservoirs (Table 1).

Figure 1. Categorresources in Chin

(Bureau of Statist

Size Storage capacity (million m3) Number TotLarge >100 470 419Medium 10-100 2,934 82.

Small


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Potential of reservoir fisheries developmChina lies across a range of climatic zones and reservoirsareas of different climatic, geographic and topographic cpotential of reservoirs for fisheries development varies bindividual reservoirs.

Reservoirs in the northeastern China have the highest ferorganic content in the soil of the watershed area. Howevwinter with very low temperature in this region, growth animals is slow. Nevertheless, the productivity is still higof this region than in reservoirs of most other parts of Chman reser oirs in the area can reach 230 kg ha-1 ear-1 (

Figure 2. Total number and storage capacity of reservoautonomous region / MDUCG (Ministry of Agriculture, 2

0

2000

4000

6000

8000

10000

12000

14000

Hunan

Jiangxi

Sichuan

Guangdong

Hubei

Shandong

Yunnan

Anhui

Guangxi

Zhejiang

Chongqing

Fujian

Henan

Guizhou

Jielin

Hebei

Shaanxi

Hainan

Liaoning

Jiangsu

Shanxi

Heilongjiang

X i j i

Numberofreserv

oirs

Province

Number of reservoirs Total storage capacity (billion


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lower reaches of rivers at the low altitudes and the environthese reservoirs are more or less stable. Also, they are biolo

As such, these reservoirs are suitable for fisheries developm

Biological characteristics of reservoirs

Natural food organisms

The availability of natural food organisms in reservoirs is thebasis for fisheries production. Planktonic organisms are the food organisms in all reservoirs. In many reservoirs, phytoplusually ranges between 5-10 mg l-1. In Fengman reservoir (aJilin province) plankton biomass was as high as 10.86 mg l-1smaller reservoirs, the phytoplankton biomass can be much mean phytoplankton biomass in Kunlong Reservoir (188.7 ha

province is 20.57 mg l-1

(Xing, 2007). On the other hand, andzooplankton biomass is lower, and in Fengman reservoir was1986). Overall, however, and compared to other kinds of inlzooplankton biomass is much higher in reservoirs. ZooplanktKunlong reservoir was 19.48 mg l-1 (Xing, 2007). Benthic animimportant group of food organisms in reservoirs. Benthic bioin Fengman reservoir (Zhang, 1986) and 3.34 g m-2 in Guanyi

2006).

Reservoir fish fauna

The information on the fish fauna of Chinese reservoirs is reGenerally, reservoir fish fauna are less complex than other iparticularly lakes. This might be due to specific hydrologica

in reservoirs. Since reservoirs in China are located in differeclimatic zones, fish fauna in different reservoirs also vary grin a reservoir in Liaoning province of northeast China is repospecies belonging to nine families (Liu, 2003). Of these, 21 family Cyprinidae (Table 2).


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Family NameSalangidae Protosalanx hyalocranius (Abbott)*Cyprinidae Tribolodon brandtii(Dybowski)

Phoxinus lagowskii(Dybowski)

Ctenopharyngodon idella(Val.)*Opsariichthys bidens(Gunther)Megalobrama amblycephala(Yih)*Chanodichthys erythropterus(BasileHemiculter leucisculus(Basilewsky)Rhodeus sinensis(Gunther) sp.

Abbottina rivularis(Basilewsky)

Romanogobio tenuicorpus(Mori)Gobio soldatovi(Berg)Gobio rivuloides(Nichols)Gnathopogon chankaensis(Dyb)Pseudogobio vaillanii longirostris(MGnathopogon notacanthus (Berg)

Table 2. Fish fauna in Beishi reservoir (Liu, 2003; * = in

Introduced fish species

As an effort to improve fish faunal composition in reservoof natural productivity, introduction of fish species has beout in Chinese reservoirs since the 1950s. However, the sto introductions being mainly across different watershedspecies such as grass carp, silver carp, bighead carp, Pro(Abbott), Megalobrama amblycephala(Yih), Hypomesus oPlagiognathops microlepis(Bleeker) have significantly im

Introduced fish species play a very important role in reseChina. Silver and bighead carp constitute the major sharemost reservoirs in China. Introduction of fish species alsothe fish fauna in many Chinese reservoirs. Species such aamblycephala, H. olidus, N. taihuensisand P. microlepispropagating populations in many reservoirs.


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Fisheries

Utilisation of fisheries resources in reservoirs of Ch

China has a long tradition in managing inland fisheries. In nereservoirs, fisheries activities usually start immediately aftewater. Fisheries development in new reservoirs is also consieffective way to provide new livelihoods to the people dispconstruction of a reservoir. The economic activities associat

include hydropower generation, forestry, fisheries and more

In China, approaches for utilisation of the potential for fishereservoirs includes capture fisheries, culture based fisheriesand intensive aquaculture. Capture fisheries are usually carfishers. Culture based fisheries are usually practiced by comcompanies or individual families. Intensive aquaculture is us

companies or individual families.

Reservoir area utilised for culture based fisheries in China dshows a steady growing trend (Figure 3). About 83% of the tChina is used for culture-based fisheries.

Figure 3. Reservoir area with culture based fisheries in C

1995-2006 (Bureau of Fisheries, 1995-2007).

2000)

1500

1000ha

1000

aUsed(

500

Ar


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conditions may produce as high as 2 tonnes/ha of fish. Foproduction of Huayuan reservoir (246 ha, water depth 19

2,032.52 kg/ha in 2004 (Gao, 2006). However, fish produckg/ha in many large reservoirs in China.

In the past few decades, there has been considerable impfisheries management in China, mainly improved stockingmanagement in fishing activities. These resulted in signifiproduction. This is exemplified by the steady increase of

during 1995-2006 in reservoirs that practice culture baseHowever, trends in fish yields from capture fisheries are nstatistical data.

Figure 4. Total and unit production from reservoir cultChina during 1995-2006 (Bureau of Fisheries, 1996-20

2000

2500

3000

Total

Production

(1000

ton) Unit

prod

(kg/ha)

0

500

1000

1500

1995 1996 1997 1998 1999 2000 2001 2002

Product

ion

Undoubtedly, increased reservoir fisheries production in Csignificantl to national fish prod ction Ho e er the e


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management authorities are established. Fisheries activitiesreservoirs are often managed by groups of displaced inhabit

or by a company. In small reservoirs, fisheries are managed or families.

Main fisheries strategies

As mentioned above, there are three types of reservoir fishe

capture fisheries, culture based fisheries (extensive culturefarming. The fisheries strategies vary according to these thr

Capture fisheries are usually operated by individual fishers, traditional fishing gears such as gill nets, traps of different (sometimes assisted with light attraction) and floating dragnfishers need to be licensed by the reservoir fisheries manage

These fishers are permitted to fish only naturally recruited sspecified mesh sizes of fishing gear in specified areas.

Culture based fisheries are usually operated by companies/cor individual households depending on the size of the reservresponsible for looking after all production links from stockito harvesting. The fishing operation is usually run on large s

gears such as gill nets, blocking nets, driving nets and set-b

Intensive culture in reservoirs includes pen and cage culturepracticed mainly in shallow reservoirs. It is usually operatedhouseholds. Cage culture is commonly practiced in relativelytakes advantage of good water quality. Cage culture operatcan be operated either by commercial companies or individ

Statistical collections

Fisheries statistical data are collected by fisheries administrthe local level. These statistical data are verified by the stasame administrati e le el before reporting to the higher ad


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are expected to play a vital role in reservoir fisheries mafuture.

Marketing

Fisheries products from reservoirs are marketed in differto the practices and scope of fisheries activities. For fishecommunity groups and companies, there are well establichannels. They usually have access to distant markets th

better benefits. Community groups and companies often storage and processing facilities, which can increase the Tourism and restaurant business are also responsible for ifisheries products.

Individual fishers in small-scale fisheries do not have accewhere fisheries products could fetch higher prices. The fi

in small-scale fisheries are therefore sold to local and neEstablishment of fishers organisations may help small-scamarket access.

Socio-economics of reservoir fisheries

Compared to crop farming and forestry, fisheries productrelatively higher incomes for rural households. Thereforeof fishers is much higher (on the magnitude of about 80%from agriculture. On the other hand, fishing and aquaculrelatively tough occupations compared to other economiagriculture and as such, they are less attractive to the yo

Current research

Since the late 1950s, a considerable amount of research carried out with the support from central and local goverreser oir fisheries in China co ers the follo ing major are


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Constraints to reservoir fishery developme

In the past two decades reservoir fisheries have witnessed rChina in terms of production. However, their development iconstraints in the ensuing years.

Physical condition of reservoirs

Global warming and other climatic changes result in irregul

areas of China. Frequent instances of low rainfall have causreduction in water area and depth of reservoirs. Soil erosionsedimentation in some reservoirs. These problems significanproductivity in the reservoirs.

Biological and environmental constraints

Eutrophication is a common problem in many inland water benvironmental degradation is caused by numerous factors aeconomic development. Protection and restoration of aquatof greater concern of the government and the public. Fisheaquaculture have become easy targets to be blamed for envdegradation. More and more strict regulations are imposed aquaculture in inland water bodies including reservoirs. Cag

discontinued in some reservoirs, which are mainly used for wareas.

Eutrophication of reservoirs also affects the reservoir fisherways. Serious eutrophication alters the species compositionin reservoirs. Population densities of fish species of high ecodeclined significantly in some reservoirs. Degradation of wa

affects the growth of fish and feed conversion in cultured baquaculture.

Socio-economic constraints

Presentl c lt re based fisheries are the main approach to


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Policy constraints

Reservoir fisheries are a relatively small contributor to thindustry so it receives very limited attention from the goreservoirs are located in remote areas where it is relativesupport systems such as technical extension services andinfrastructure is usually weak. Fishers and aquaculture ovulnerable to natural disasters.

Future strategies

Reservoirs are an important natural resource with multipwith very high population density, in China the per capitais low. As a result, land based economic activities such aslittle scope for contributing to furthering the rural econo

management, economically and ecologically sound fish pfrom reservoir fisheries. As such, reservoir fisheries can pimproving fish supply and generating income for the ruralong-term sustainability of reservoir fisheries of China, thare important.

Development of eco-friendly fisheries in reservo

In the past, reservoir fisheries were fish production-centrwas inadequate to meet the demand in China. Presently,the demand so that environmental concerns are prevalenmanagement to produce fish without adverse impacts on conserving fisheries has become a concept accepted by for long-term sustainability of fisheries.

Furthermore, good reservoir fisheries practices will help degradation of the aquatic environment, particularly eutIn future strategies, reservoir fisheries should be studied perspectives.


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Bureau of Fisheries, 2003.China Fisheries Statistics YeaFisheries, Beijing, China.

Bureau of Fisheries. 2004.China Fisheries Statistics YeaFisheries, Beijing, China.



Bureau of Fisheries. 2007.China Fisheries Statistics YeaFisheries, Beijing, China.

Bureau of Statistics, 2007. China Statistics Yearbook 200

Press, Beijing, China.

Chen, X., 2006.Practice and discussion on investigation fisheries resources in You Xi Jie Mian Reservoir in Fujian pFujian Fisheries,1: 84-86.

Gao, Y., Xu, Q. et al., 2006.Technical measures for con

and efficiency of fisheries in Huanyuan Reservoir. Reservo

Hu, C. and Huang, D. et al. 2005Study on coordination development and multi-functions of large and medium reReservoir Fisheries, 25 (5): 1-4.

Liu Z. and Tang Z. et al., 2003.Baseline survey of fisher

Reservoir. Reservoir Fisheries, 23: 43-46.

Ministry of Agriculture, 2006.China Agricultural YearboAgricultural Press. Beijing, China.

Shi W 1996 Fish Enhancement and Aq ac lt re in Inla


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Achievements, Challenges and S

Reservoir Fisheries DevelopmentJiashou Liu, Zhongjie Li and Songguang XieState Key Laboratory of Freshwater Ecology and Biotechn

Hydrobiology, the Chinese Academy of Sciences, 7 South

430072, P.R. China.

Introduction

Aquaculture has been conducted in China for more than 3reservoir fisheries are a new sector in China, which have large-scale construction of water projects. More than 86,

been built in China for irrigation,flood control, power gein a little over five decades. As a result, two million hect

suitable for fish production have become available (Wu, 1China are classified into three types based on the surfacearea > 667 ha), medium (surface area between 67 - 667 harea < 67 ha). There are more than 400 are large sized reare medium sized and more than 8,200 are small sized.

China is densely populated. The construction of reservoira large area of agricultural land, resulting in the displaceof people. In compensation for the loss of agricultural lagovernment emphasised the development of reservoir fisalternative livelihoods to displaced people.

In the past 60 years or so, China has made much progressdevelopment and management. On the other hand, the dfisheries in China has also encountered some challenges. achievements of reservoir fisheries in China are reviewedhighlighted and development strategies are discussed witstrategies for the s stainable de elopment of reser oir fi


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recruitment seasons and controlling the size at capture werHe, 1992). With the success of artificial propagation of the f

(silver carp Hypophthalmichthys molitrix, bighead carpArisgrass carp Ctenopharyngodon idellaand black carp Mylophastocking of fish into small- and medium-sized reservoirs becfisheries practice. This not only brought about significant ecbut also helped to employ a lot of displaced people. For exain Fuqiaohe Reservoir, Hubei Province (1,340 ha), increased to stocking to 300 tonnes after stocking and more than 300

were employed asfish farmers or

fisheries management of

fi

1998). The main achievements of Chinese reservoir fisheriesRapid increase of fish production in reservoirs.Establishment of stocking and fisheries management systeFish productivity assessment in reservoirs.Improvement of capture techniques.Improvement of fish escaping avoidance techniques.

Standardi sation and extension offisheries techniques.

Rapid increase of fish production in reserv

Fish yield from reservoir fisheries was only 54,000 tonnes inthe Peoples Republic of China was founded. With the libera

economy in China in 1978, consumption patterns of people cresult of increased buying power. Consequently, fish yields fincreased from 112,000 tonnes in 1978 to more than 2.23 m(FBMA, 2006) (Figure 1), currently averaging nearly 1200 kgreservoir fisheries sector is considered to have still more podevelopment. Reservoir areas suitable for fish production reof the total freshwater area in China, but the fish productio

represents only 11.7% of the total freshwater production (F2). Therefore, reservoir fisheries could play a more importa

Establishment of stocking and managemen


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Figure 1. Reservoir fish production and surface area fr

1500

2000

2500

d(x1000t)

Area(1000*ha) Yield(t) Yield/ha

0

500

1000

1978

1979

1980

1981

1982

1983

1984

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

Area(x100ha)/Yiel

Figure 2. Percentages of surface area (ha) of different and fish production thereof (in tonnes), currently.

Rivers

381,533

7%

Other

201,479

3%

Ponds

2,495,361

43%

Reservoirs

1,808,027

31%

Lakes

964,088

16%

area (ha)

Lakes

1,234,193

6%

Reservo

2,229,30

12%

Production (t)


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New icefish (Neosalanx taihuensis) and large icefish (Protoshave also been stocked in recent years. Icefish is small sized

Its lifespan is only about one year. They reproduce naturallyeasily captured. The total production of this small-sized newNew icefish is translocated into reservoirs in Southern and Clarge icefish is introduced into reservoirs in Northern China few years after introduction, icefish is able to support commMany reservoirs benefit from the introduction of icefish, espYunnan, Hubei, Jiangsu, Shongdong and Inner Mongolia.

Reservoir fisheries are under the jurisdiction of the Chinese Resources. However, all other fisheries including marine fishfrom ponds, lakes, rivers and rice fields are under the admiChinese Ministry of Agriculture (Wu, 1998). In most medium reservoirs, an administration agency is set up to manage thesale and water resources. Usually, a hatchery is built below

and large reservoirs to supplyfingerlings for stocking. For nebuilding a fish hatchery is required by law.

Fish productivity assessment in reservoirs

Almost country-wide survey of reservoir limnology was made

Different types of reservoirs were identified based on morphcharacteristics, principal nutrient concentrations and bioma

organisms (Dai and Xu, 1996). The methodology was developcarp and bighead carp production from phytoplankton prima(1996), based on the analysis of 15 factors affecting fish yiehas shown that mean depth, catchment area, water temperdissolved oxygen content, total phosphorus, phytoplankton

number of stockedfingerlings are the major factors in

fluencfactors can be used as an ecological index for estimating fis

Improvement of capture techniques


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as common carp and Crucian carp, can also be harvestedImprovement of fish escape preventing techniques.

Fish escapes from reservoir spillway and turbines are a cocausing great losses for fish farmers. A new electric faciliprevent fish escaping from reservoirs. This facility can boturbine and spillway area and block the fish from escapin

Figure 3. Sketch map of the united fishing method in a

(Modifi

ed from Li and Xu, 1995)

Standardisation and extension of fisherieIn order to standardise the fisheries practices in reservoiregulations have been established, as listed below.

Standard for the Investigation of Reservoir Fishery ResStandard for the Fisher Trophic Classification (1999)


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A full extension system of reservoir fisheries techniques has including research, training and production. There are fishe

institutes from central government level to provincial levelgovernment level, the Chinese Academy of Fisheries ScienceMinistry of Agriculture, the Institute of Hydrobiology attachAcademy of Sciences, National Engineering Centre for Freshattached to the Ministry of Science and Technology, and theecology (originally Reservoir Fisheries Research Institute) atMinistry of Water Resources are relevant to reservoir fisheri

are more than 15fi

sheries journals published in China, incluReservoir Fisheries.

Challenges to development of reserv

Even though reservoir fisheries have achieved a significant s

encountered challenges, some of which being associated wiof the economy and the increased living standards of peopleinclude, the demand for higher quality food fish, and the redemand and hence the price of species used traditionally infisheries, the conflict between aquaculture and the environneed to rationalise the stocking practices, prevalence of suddisease problems and an imbalance of the fisheries develop

regions, and the low economic returns from cage culture.

Simplification of species cultured in reserv

Species composition of fishes used for reservoir stocking in Cby silver carp and bighead carp. However, there are disadva

with these species although they contribute signifi

cantly to fisheries. They have low market value. Also high stocking ragain good economic returns, which increases investment anfisheries on water environments (Liu et al., 1998). Since thethey are restricted to the upper part of water column and amiddle and lo er parts of the ater col mn are irt all n


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Generally speaking, over-stocking of silver carp and bighethe protection of water quality and economic efficiency.

Irrational structure of stocked fish popu

In China, piscivorous fishes are not considered as stockingThey have been thought to be harmful to stocked fingerlicaptured thoroughly (Chen et al., 1978). As a result, the

have become suitable for the growth and reproduction ofof the middle and lower reaches of the Yangtze River, thespecies amounts to more than half of the total fish specie1998). The food conversion efficiency of trash fish is genepresence of trash fish in high abundance also decreases tof reservoirs. On the other hand, the trash fish compete fish, which also conflicts with fisheries production. Furthe

is almost a waste resource in reservoirs because of the lamethods and low market price (Liu and Hu, 2000).

Prevalence of the sudden and violent fish

For a long time, reservoirs have been famous for good wa

prevalence offi

sh diseases has not been a problem. In thethe suddenand-violent fish diseases have been very comreservoirs as a result of intensive culture such as cage cuand applications of fertilisers, which cause big losses to fi1997). It is predicted that with the development of cultuintensity, this disease will be even more harmful.

Imbalance of the development

The development processes of reservoir fisheries in Chinain different areas. The average annual reservoir fish yieldkg/ha Ho e er in the de eloped areas s ch as in Centra


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had insufficient pond capacity for fingerling rearing (Liu andspecies cultured in this period were silver carp and bighead

and reservoir administration units benefi

ted from this new cthe two species cultured fed on naturally occurring planktofeeds were used. In the recent years, with the developmentand the higher demand for high quality fish, cage culture wior live organisms has become popular in reservoirs all over Cculture did not produce good economic returns for fish farmthe following problems.

High feed cost. Irrational cage structure and location of cages in the watLow price for cage cultured species.

High feed costs

The ratio of feed price to product price is over 70% for cagecarp and grass carp, which discourages fish farmers to engagOne of the reasons for the high fish feed cost is that almost China are imported. Furthermore, several other reasons exiwastage of feed. As the determination of ration for cage cusolely on observations, feeding regimes and quantities bringfeed. The irrational feeding methods involving the feeding f

times per day within a short period also lead to waste of feeformulation techniques are also responsible for feed waste.are normally not bond well and powders represent a certainThese feeds are easily dissolved in water and also blown awalso increases feed conversion rate (Liu et al., 1997). Insuffiabout fish nutrition is also responsible for producing nutritiofeeds. The feed conversion rate for cage culture is about 1

countries (Beveridge, 1987), but it is about 1.5 or more in C

Irrational structure and location of cages i

body


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Low price for cage cultured species

The common species cultured in cages include common ctilapias. Although they produce high yields, the economiclow price. This leads to less enthusiasm of fish farmers in

Conflicts between reservoir fisheries and

protectionWith the increasing deficiency of water resources and furwater quality, the conflict of reservoir fisheries with envibecomes more serious (Liu et al., 1997). People are concpollution caused by cage culture in reservoirs. In Gaobaza surface area of about 500 ha in Hubei Province, the wavery good (type II water by Chinese standards) ten years aproliferation of the large scale cage culture of the Amerithe water quality has highly deteriorated (type IV water)the environmentalists are much concerned about cage cuexample, in the Three Gorges Reservoir, the biggest reseculture is completely prohibited.

Future strategies

For sustainable development of reservoir fisheries in Chinare needed to be considered. Perhaps the renewal of stoeffective strategy instead of the traditionally stocked plasilver carp and bighead carp, which have low market demdirected towards selection of high valued planktivorous fipartially replace the traditionally stocked species shouldpriorities. In the early 1990s, the icefish N. taihuensis, a mainly feeding on zooplankton, was stocked into some reand Southwestern China. Many reservoirs are benefiting fFor e ample Zhanghe Reser oir an oligotrophic reser oi


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that large-scale capture with the United Fishing Method (Li not necessary. Furthermore, fishers in reservoirs with the nebenefited by selling fertilised eggs. In 1997, fishers in Zhang54.45 million icefish eggs and earned about 1 million Chines

The American paddlefish Polyodon spathula, a planktivorouson zooplankton, perhaps is another alternative for partial rebighead carp. This species is known for its high quality meateggs in North America (Liu and Yu, 1990). Since the early 19been introducing the American paddlefish every year from tIt showed high growth rates both in the open water and cageasily caught with gill nets and it may spawn and hatch natureservoirs (Liu and Hu, 2000). Also, presently the artificial pAmerican paddlefish is successful in China so that import ofStates is no longer a necessity. The only concern is that the may escape from stocked reservoirs into the Yangtze River athe endangered Chinese paddlefish Psephurus gladius.

Silver carp and bighead carp only use the trophic spatial nicin reservoirs. As such, there appears to be a provision to stointo reservoirs in order to enable full use of the food resoura reservoir ecosystem. The common carp C. carpio, a benthcommonly found in Chinese lakes, but large populations of tfound in Chinese reservoirs because of the lack of aquatic pspawning substrates. Most of sturgeons live in the bottom laand feed on benthos. Reservoirs provide good water quality their growth. Sturgeons generally grow faster in reservoirs tbe easily caught by gillnets (Wei, 1985). The rivers in the upsized reservoirs may be suitable for the reproduction of sturStocking sturgeons into reservoirs perhaps is a rational choicuse of reservoir resources and improving economic situation

The organic detritus is an important food resource of fishes Heilongtan Reservoir, a eutrophic reservoir of 1693 ha in Sicannual fish production potential based on organic detritus w473 tonnes (Chang 1995; H et al 1998) Ho e er large fi


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fishery products. Furthermore, piscivorous fishes commanand a lower stocking rate may produce a higher economipressure of fisheries (Liu et al., 1998). Studies in North Ashowed that stocking of piscivorous fishes into lakes coulby trophic cascading effects (Carpenter and Kitchell, 198Determination of appropriate stocking number of piscivois important. Bioenergetics models can be used to predicconsumption of fish (Hewett and Johnson, 1992; Brandt aStudies of the productivity of trash fish in a reservoir andmodel of the piscivorous fish will help determining the aprates of piscivorous fish based on predator-prey relations

Catching demersal fish efficiently in reservoirs is somewhstudies on fishing gear technology for capture of demersa

Cage culture practices also need to adopt changes, such location of cages in a water body, which will increase thedecrease pollution, and control incidence of diseases (Pe

A strategy to develop intensive culture of high-valued fishdischarged water below reservoir dams needs to be exploBeijing, several different cold water fish species such as are cultured, resulting in good economic returns. Througpractices, water pollution can be efficiently controlled.

Carrying capacity of reservoirs for aquaculture is a main years because of the deteriorated water quality in reservdetermining the carrying capacity of reservoirs with diffebe established. A standard method for assessing the carrybody for cage culture has been developed (Peng et al.,2validated. Carrying capacity of reservoirs for other aquacalso be developed.

Acknowledgements


35/124

Brandt, S.B., Hartman, K.J., 1993.Innovative approaches models: future applications to fish ecology and managemen

American Fisheries Society, 122: 731-735.

Chang, X., 1995.Preliminary studies on particulate organicHeilongtan Reservoir. Reservoir Fisheries, (3): 24-27 (in Chin

Chen J., Lin Y., Wu Z., 1978.Regularities of succession of population in reservoirs of the middle and lower Chang Jiangdiscussion on the methods of population control. OceanogiaSinica, 9: 49-58 (in Chinese).

Carpenter, S.R., Kitchell, J.F., 1988.Consumer control of BioScience, 38: 764-769.

Dai, Z., Xu, X., 1996.An approach to eutrophication classifireservoirs. Reservoir Fisheries, 2: 3-6 (in Chinese).

Deng, X., 1992.Fish culture with fertilisers. Hunan ScienceChinese).

Gao, H., Chen, C., Lin, Y., 1997.Epidemiological investigadisease of fishes and its prevention treatment in some reserFisheries, 1: 8-10 (in Chinese).

Hewett, S.W., Johnson, B.L., 1992.Fish Bioenergetics ModWisconsin, Sea Grant Institute, WIS-SG-92-250, Madison.

Hu, C., Lin, T., Wu, H., Gao, H., Chang, X., 1998.Studies fishery exploitation of Heilongtan Reservoir in Sichuan ProviInternational Reviews in Hydrobiology,83(special issue): 53

IHHP (Institute of Hydrobiology of Hubei Province), 1976.Yangtze River.Science Press, Beijing (in Chinese).

Li S X S 1995 C lt re and capt re of fish in Chinese


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Liu, J., He, B., 1992. Cultivation of the Chinese freshwScience Press, Beijing, 750 pp (in Chinese).

Liu, J., Hu, C., 2000.Sturgeons and their status and funfisheries, Reservoir Fisheries, 20: 1-4.

Liu, J., Huang, Y., 1998.Fisheries and fish culture practReservoir, China. International Reviews in Hydrobiology, 576.

Liu, J., Peng, J., Yu, F., Jiang, J., Yao, X., Yi, Y., 2001new icefish Neosalanx taihuensisyield in Zhanghe ReservSilva, S.S. (ed.). Reservoir Culture-based Fisheries: BioloProceedings of an International Workshop held in Bangko

18th February 2000.Australian Centre for International ACanberra.

Liu, J., Yu, Z., 1990.The paddlefish (Polyodon spathulaUSA.Acta Hydrobiologica Sinica, 14(1): 75-83 (in Chinese

Liu, J., Cui, Y., Liu, J., 1998. Food consumption and grofishes, the mandarin fish and the Chinese snakehead.Jou1071-1083.

Liu, J., Yu, Z., Dai, Z., 1992. Present status and prospecin China. In: Reservoir Fisheries of Asia. Proceedings of tFisheries Workshop held in Hangzhou, Peoples Republic

1990.Interntional Development Research Center, Ontario

McQueen, D.J., 1990.Manipulating lake community strufrom here. Freshwater Biology, 23: 613-620.

Peng, J., Liu, J.,Xiong, B., 2004. Carrying capacity of wculture.Acta Ecologica, 1: 28-34.

Wei Q 1985 An approach to de eloping st rgeon fishe


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38/124

Status of Reservoir Fisheries in I

K.K. Vass1and V.V. Sugunan2*

1. Central Inland Fisheries Research Institute, Barrackpo

2. Indian Council of Agricultural Research, New Delhi, In

IntroductionReservoirs contribute considerably to the inland fish prodhas been estimated at 93,000 tonnes (Anon, 2006) In spitfish production has been treated as a by-product, giving ias a fish production system. For this reason, reservoir fishmade significant progress in the country and do not contrproduction of the country to the extent they could. Howemanagers of a majority of the water and power projects realised that fisheries need to be given its due importancmanagement. Unlike rivers, which are under increasing tdegradation, reservoirs in India offer ample scope for fishthrough effective management (Vass, 2007). The sheer mresource makes it possible to enable substantial increasea modest improvement in yield. Further, the importance mainly from advantages from environmental and social pof increased yield and income generated of fishing commmore equitably distributed. There is also a need to dovetof yield optimisation and environmental conservation.

Reservoirs

Government of India defines reservoirs as man-made impobstructing surface flow, by erecting a dam of any descrior any water course. However, water bodies less than 100e cl ded from this definition The Ministr of Agric lt re


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Karnataka has the most large reservoirs (twelve), but the towhen compared to the cumulative extent of seven reservoir

Morphometric and hydrological features

In reservoir ecosystems, climatic and edaphic factors are refixation and nutrient dynamics, thus considered to be of firsfollowed by morphometric factors (basically area, mean depshoreline) having significant bearing on productivity.

Mean depth (volume/area) in reservoirs is considered to be important morphometric parameters indicative of the extenlittoral zone (Rawson 1952, 1955). A relationship between fibeen worked out in some African reservoirs by Henderson an

Henderson et. el, 1973) For a few Indian reservoirs MEI was Ramakrishna (1990) but no statistical relationship was estabdeeper reservoirs of India with mean depth of 21.1 m and 1productivity. However, other deep reservoirs such as Bargi (Pradesh, Chamera (43.5 m) and Govindsagar (55.0 m) in HimRihand (22.8 ha) in Uttar Pradesh, and Badua (14.5 ha) in Bidue to other favourable factors. Thus, it appears that in Indis not always a constraint to productivity. Fortunately, mostmedium sized reservoirs are of low mean depth (4-7 m) andpotential.

Table 1. State-wise area of small, medium and large reser

State Small Medium LTamil Nadu 315,941 19,577 23

Karnataka 228,657 29,078 179Madhya Pradesh 172,575 149,259 138Andhra Pradesh 201,927 66,429 190Maharashtra 119,515 39,161 115Gujarat 84 124 57 748 144


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State Area(ha)

Mean depth(m)

Eleva(m m

Jammu & Kashmir NA 25 NAHimachal Pradesh 900-15,000 20-55 440-8Punjab 46-280 4-10 NAHaryana NA 3.4-5 NARajasthan 165-1,554 1.7-7.7 NA

Uttar Pradesh 17.5-30,149 3-22.8 119-2Madhya Pradesh 77-66,000 3.4-14 348.7Bihar & Jharkhand 21-3,733 5.2-14.6 NAWest Bengal NA 3.2-11 NA

Table 2. Average range of some morphometric and hydsome reservoirs in different states.

The Indus basin catchment is comparatively less fertile thbasin where gangetic alluvial soil boosts productivity of tof the basin as a whole (CIFRI, 1986). The Gangetic basinwith intensely cultivated agricultural lands with a moder(250-4000 mm). In contrast, the upper Indus flows througemerging onto the plains in the lower reaches, also receiless rainfall (100 mm) in the lower plains than in the uppThe predominant soil formation is an illitic clay dominatewith high potassium content and moderate nitrogen and in the Gangetic basin while the Indus basin soils are poorthe upper reaches, with low to moderate nitrogen and phin Punjab, Haryana and Himachal Pradesh (CIFRI, 2006). Tis augmented due to the application of inorganic fertiliselands. Temperature in the upper regions is 2-16C compa24-35C.

De Silva (1988) suggested that in shallow reservoirs, the as a source of autochthonous nutrient loading. However, has been noticed that the catchment determines the watextent than the basin soil (Natarajan, 1976, 1977, 1979; The e tent of catchment has a positi e impact on the res


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the majority of Indian reservoirs drastic fluctuations in wateobserved to impact plankton, benthos and periphyton pulsesthe period of least water level and that all the communitiesduring the months of maximum water level and water disch

Physico-chemical features of reservo

Coarse and fine sand predominate the basin soil in the majoof Rajasthan, Haryana, Uttar Pradesh, and Punjab followed Himachal Pradesh, Jharkhand and West Bengal. Silt depositimainly along the river course and thus in majority of the resplains the sediment is mostly sandy-clay type.

Chemical characteristics

Soil reaction

Soil is mostly neutral to moderately alkaline in reservoirs reproductive trend. Moderately acidic basin soils were observin Bihar and Jharkhand due to the forest-covered catchmenphosphorus is basically dependent on soil pH. Bottom sedimlevel of organic matter with slow decomposition rate develohumic and short chain fatty acids, leading to less productiviDas, 2003). The favourable pH range for biological productiv

Nutrients

Available nitrogen

Nitrogen is the basic and primary constituent of protein andin soil in organic form getting mineralised gradually to ammnitrate (NO

3-) forms thus making their availability to fish foo


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Reservoirs in Punjab, Himachal Pradesh, Madhya PradeshWest Bengal having moderate available nitrogen content high productivity.

Available phosphorus

Soil available phosphorus (mg/100g soil) should be in thehigh biological productivity but it is of low profile in India(mg/100g) in reservoirs, especially in Punjab, Himachal PKashmir, Haryana, was of very high order while it was low

Organic matter and carbon : nitrogen ratio

As per available data comparatively low to moderate orgis recorded in most of the Indian reservoirs. Generally bo1.5-2.5% organic carbon is considered to be productive.

Nitrogen mineralisation or immobilisation is solely governnitrogen (C:N) ratio - the higher the C : N ratio (>20) highof inorganic nitrogen as compared to lower C : N ratio ( 10,000

Floodplain lakes (natural)Upland hydroelectric reservoirs (recent) 7

Mahaweli multipurpose system ofreservoirs (recent)OtherTotal 1

Fish fauna in reservoirs of Sri Lanka

In Sri Lankan freshwaters, 85 native fish species belonging treported to occur (Newrkla and Duncan, 1984; Silva and DavPethiyagoda, 2006; Weliange et al. 2008). In addition, 24 exbeen introduced to Sri Lankan freshwaters since late nineteand three of them (Chitala ornatus, Clarias batrachusand Pmultiradiatus) are accidentally introduced exotic fish specie

et al., 2006; Shirantha and Amarasinghe, 2006). Since the intwo exotics Salmo truttaand Onchorynchus mykissduring tcentury for purposes of establishment of sport fishing, severhave been introduced either deliberately or accidentally intfreshwaters. Introduction of most exotic species during the was to develop inland fisheries in Sri Lanka (Amarasinghe, 1to the differences in habitat preferences, reservoir fish com

essentially similar to the fish communities in associated riveof fish species reported to inhabit in the reservoirs of Sri LaTable 2.

A productive fishery was established in reservoirs of Sri Lintroduction of the exotic cichlid species, Oreochromis mcountrys freshwaters in 1952 (De Silva, 1988). The dram


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fish production in Sri Lanka is best exemplified by the treParakrama Samudra reservoir during 1950s and 1960s (Fig

The capture fisheries in major reservoir of Sri Lanka are cfollowing: (a) the use of non-mechanised fiberglass canoein length manned by two persons; (b) the gear used compgillnets (6-20 net pieces per craft), ranging in mesh size f

cm, with each net piece being of a standard length and hm, respectively; and (c) the predominant catch is exotic mossambicusand O. niloticus.

Figure 1. Trends in the fishery of Parakrama Samudra r1967 (Adopted from De Silva 1988).

50

100

500

10

5

CAT

% O

O. mossambicus

Entering the

shery

Introduced

T

OTALCATCH(mt)

Table 2. List of fish species reported from the reservoirs o(De Silva 1988; Amarasinghe and Samarakoon, 1988; AmaWeliange et al., 2008). * = Exotic.


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Family/species Max. length

(cm)

Contribution to th

Anabantidae

Anabas testudineus 25.0 Not caught in majo

Anguillidae

Anguilla bicolor bicolor 120.0 Caught in some res

A. nebulosa nebulosa 120.0 Caught in some res

hooks

Bagridae

Ompok bimaculatus 45.0 Low contribution t

Wallago attu 240.0 Rarely caught in so

Channidae

Channa striata 100.0 Caught in small pe

Cichlidae

Etroplus maculates 8.0 Not caught in comm

E. suratensis 28.0 Low contribution t

Oreochromis mossambicus* 42.0 Major species in th

O. niloticus* 46.0 Major species in th

Tilapia rendalli* 34.0 Caught in some res

Clariidae

Clarias batrachus* 47.0 Accidentally introd

fisheries industry;

C. brachysoma 50.0 Widely distributed

Clupeidae

Ehirava fluviatilis 5.6 Not caught in comm

Cobitidae

Lepidocephalichthys thermalis 8.0 Not caught in comm

Cyprinidae

Amblypharyngodon melettinus 8.0 Very abundant but

Aristichthys nobilis* 112.0 Hatchery reared fin

small village reserv

Catla catla* 182 0 Hatchery reared fin

Family/species Max. length

(cm)

Contribution t

Garra ceylonensis 15.0 Not caught in c

Hypophthalmichthys molitrix* 105 0 Hatchery reare


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Hypophthalmichthys molitrix 105.0 Hatchery reare

small village re

Labeo dussumieri 35.0 High catches du

reservoirs

L. rohita* 75.0 Hatchery reare

small village re

naturally breed

Puntius bimaculatus 7.0 Not caught in c

P. chola 15.0 Very abundant

fisheries

P. dorsalis 25.0 Abundant but n

fisheries

P. filamentosus 18.0 Very abundant

fisheries

P. sarana 30.0 High catches du

reservoirs

P. vittatus 5.0 Not caught in c

Rasbora caverii 10.0 Not caught in c

R. daniconius 15.0 Abundant but n

fisheries

Tor khudree 50.0 Rarely caught i

Gobiidae

Glossogobius giuris 35.0 Low contributio

Hemiramphidae

Hyporhamphus limbatus 25.0 Small-scale fish

Heteropneustidae

Heteropneustes fossilis 30.0 Not caught in c

Loricariidae

Pterygoplichthys multiradiatus* 50.0 Accidentally in

fisheries indust

species in some

preference.

Mastacembelidae

in Sri Lankan reservoirs and its high contribution to fish landand Indrasena (1969) suggested that due to the extensive avshallow littoral zones in Sri Lankan reservoirs, reproductive


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O. mossambicusis high. Fernando and Holcik (1991) stated treservoirs of Sri Lanka are due to ability of exotic cichlid sptheir lacustrine habitats, which the indigenous fish fauna, laspecies and entirely comprising of riverine and marsh-dwellcannot sustain dense populations in lacustrine habitats. Cos(1978) mentioned that as O. mossambicusis able to digest tphytoplankton group, blue-green algae, which is not preferrfish species, the introduced O. mossambicus has occupied aSri Lankan reservoirs. De Silva (1985) has shown that due to

mossambicusto change its dietary habits from season to seathe availability, this species has successfully colonised reser

However, a recent study indicates that at present, O. mossathe most dominant fish species in reservoirs of Sri Lanka (Ta

reservoirs,O. niloticusis also equally dominant. ChandrasoAmarasinghe (1997) have also reported similar trends in somLanka.

Reservoir Om On Es LdBadagiriya 27.36 43.24


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Small sized cyprinids are however, abundant in Sri Lankan1967; Schiemer and Hofer, 1983). Several studies have incyprinids could be exploited using small-mesh (15-52 mmgillnets without catching juvenile cichlids (Amarasinghe, and Sirisena, 1987, 1989; Pet and Piet, 1993). Juvenile Oniloticusare only found in shallow (


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Figure 2. Relationship betweenfi

sh yield andfi

shing inteSri Lanka (adapted from Amarasinghe, 2003).

5

50

0

10 15

100

150

200

250

300

350

Fishing intensity (Boat-days ha-1

Fishy

ield(

kgh

a

-1y

r-1)

Y = 11.036X + 24.867

(r = 0.775 p < 0.01)

Amarasinghe et al. (2002b) have shown by comparing actuaseveral Sri Lankan reservoirs with the fish yields predicted b

that the predictive power of these models is very high. As inand Kapetsky (1991), GIS can be used as an effective meansand processing for a wide range of planning and managemenUsing the models presented in Table 2, extents of different catchment areas of reser oirs that can be determined from

These analyses indicated that the optimal size of first caspecies is about 20 cm total length. Gillnet selectivity stu1988; Amarasinghe and De Silva, 1994) indicate that the

fi


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Table 4. Relationships between fish yield (FY in kg ha-1

different catchment land-uses to reservoir area (RA) a(RC). FC Extent of forest cover; SL- Extent of shrub laexpressed in km2. R2= Coefficient of determination. (S

2001; Amarasinghe et al., 2002b).

RelationshipFY = 64.931 + 43.32 ln (FC/RA)FY = 16.558 + 47.124 ln [(FC + SL)/RA]FY = -154.42 + 41.283 ln (FC/RC)FY = - 170.7 + 38.265 ln [(FC + SL)/RC]

Figure 3. Relationships between fish yield (FYFSL) andcatchment land-use types to reservoir area and reservAbbreviations are as stated in Table 4.

In (FC/RA)

40

80

120

160

200

0

3210-1

FY(kg,

ha-1y

r-1)

(A)

40

80

120

160

200

0

10

In [(

FY(kg,

ha-1y

r-1)

(B)

corresponding to this optimal size atfirst capture of cichreservoirs is 8.5 cm.

Strategies for management of capture

perennial reservoirs


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During 1979-1989 period, the government of Sri Lanka took the capture fisheries in reservoirs of Sri Lanka by providingglass canoes and gillnets under a subsidy scheme. De Silva (that as a result of this subsidy scheme, fishing effort in reseconsiderably. The fisheries authorities have also imposed fiscontrol fishing effort and size of fish landed. Use of mechan

kind of shore seine nets are forbidden in perennial reservoirpermissible mesh size for the gillnet fishery is 8.4 cm. Howemesh sizes smaller than minimum permissible size (


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In Muthukandiya reservoir, the FCS collects one Sri Lankaof fish landed from the fishers to provide a welfare fund fFCS maintains a receipt book and issues receipts to eachfor the money collected. As such, based on these recordswelfare fund, daily data on weight of fish landed by indivcollected. Through this procedure, total enumeration ofpossible in Muthukandiya reservoir. A similar community-

system is in operation in Senanayaka Samudra (7,680 ha)in Sri Lanka, where fishing trips are also regulated by thesociety (Dr. M. van der Knapp, pers. com.). Nathanael anhave also shown that co-management strategies could befishery of Victoria reservoir in Sri Lanka.

Figure 4. Trends in the inland fish production in Sri Lan

Percent contribution of the inlandfi

shery to the totalfi

indicated here (modified after Amarasinghe, 2003)

15

20

25

30

35

40

45

oductionX103(

mt)

Fish stocking in perennial reservoirs: How

Stocking of fish fingerlings is a commonly practised strategy

k h i l i l h


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stocks, enhance recreational or commercial catches, restornew fisheries (Cowx, 1994). In Sri Lankan reservoirs, stockinis carried out to enhance commercial catches. De Silva (198stocking practices in inland reservoirs of Sri Lanka and recog

First phase: stocking with giant gourami, Osphronemus gothe 1940s followed by O. mossambicusin 1950s and O. niSecond phase: stocking with Chinese major carps beginni

followed by Indian major carps in the early 1980s.

Chandrasoma (1992) reported that in three reservoirs namelKandalama (777 ha) and Udawalawe (3,374 ha), L. rohitathstocked in 1980s produced high yields. However, stocking ofnot result in high yields in majority of reservoirs (De Silva, 11998b). Fish yields of exotic carp species showed negative c

relationship with the reservoir area indicating that highfi

shstocking can only be achieved in small (


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Indian carps attached to submerged macrophytes could bareas of the reservoir. This evidence suggests that self-reof Indian major carps have been established in the Walawon the reproductive biology of Indian major carps in Sri Ltherefore necessary for defining reservoir fisheries manag

Strategies for the management of culturin village reservoirs

In culture-based fisheries, artificially propagated seed stointo water bodies not primarily and traditionally used forrecaptured upon reaching a desirable size (Lorenzen, 200

mentioned that as a rule, culture-basedfi

sheries involve as in the case of Vietnam where farmers lease out small et al., 2001), or collectively, in the form of a cooperativeoxbow lakes in Bangladesh (Middendrop and Balarin, 1999

The seasonal reservoirs are highly productive due to the accumulated in the draw-down areas from cattle grazing

residues of terrestrial vegetation. Small puddles in most do not dry up completely so that they can harbour some carnivorous fish species with accessory respiratory organs(Channaspp.), climbing perch (Anabas testudineus), catfispp.). These indigenous species, although harvested in sonot produce high yields. The potential of small village redevelopment of culture-based fisheries was first pointed Accordingly, attempts were made in 1960s to utilise thesfor the development of culture-based fisheries (Indrasena(1965) reported that in 1960s, some seasonal reservoirs wmossambicusfingerlings of 7.5-10.0 cm and that during 8retention period the gre pto 25 30 cm in si e

Table 5. Fish harvests from three seasonal reservoirs in tprovince of Sri Lanka in early 1960s. Oreochromis mossampractically the whole catch (Source: Fernando and Ellepo

area of a seasonal reservoir is considered as 50% of the el l (FSL) Th fi h i ld i i d f ff i


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Based on the recommendations by Rosenthal (1979) and Oglprogramme has been implemented to formulate a suitable sdevelopment of culture-based fisheries in seasonal reservoir(Thayaparan, 1982). De Silva (1988) estimated fish yields of reservoirs, mean survival rates and mean weight at harvestispecies in seasonal reservoirs, based on the data reported bSamaranayake (1983). These estimates indicate that fish yiecycle have varied considerably from 18 kg ha-1to 1961 kg hahighest survival was reported for O. mossambicuswhereas fwere observed for Cyprinus carpio, C. idellaandA. nobilisexperimental project was funded by FAO/UNDP (FAO/UNDP, studies have shown that there is a high potential for the devculture-based fisheries in seasonal reservoirs, Asian Developa project on aquaculture development in Sri Lanka, the maiwas the utilisation of seasonal reservoirs for culture-based fi(De Silva, 1988). This project commenced in 1984 and it alsostrengthening of 6 fish breeding centres and 8 fingerling-reawere owned by the Ministry of Fisheries (Thayaparan, 1982)

The culture-based fisheries development trials were carriedreservoirs in 1980s with rural community participation. Fingcarp, Chinese and Indian major carps of 5-8 cm size, producbreeding stations ere stocked in the reser oirs At the en

area of a seasonal reservoir is considered as 50% of the elevel (FSL). The fish yield is estimated for effective area o

Reservoir Cultureperiod

Extent atFSL (ha)

Effectivearea (ha)

Total c(kg)

Timbirigaswewa 1963 12 6 1,587Moragaswewa 1963 41 20.5 3,175Dalukanawewa 1963 12 6 1,587Dalukanawewa 1964 12 6 2,268

seasonal reservoirs exclusively rely on common carp, Chicarps. These species have been artificially spawned succe(Weerakoon, 1979; Balasuriya et al., 1983; De Silva, 1988

T bl 6 S d t il f th fi h i ld f i


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Species % Survival Mean weight (kgBighead carp 57.0 (5.0-87.3) 1.14 (0.31-2.05)Common carp 26 9 (0 37-50 0) 1 29 (0 46-4 55)

Table 7. Mean survival rates, mean weights at harvestistocked species in seasonal reservoirs in 1979/80, 198Ranges are given in parentheses.

Reservoir / Year SD Species (%)T GC BC CC L

Tunkama (4 ha)

1979/80 6250 12 44 36 8 -

1980/81 5410 53 - 19 28 -

1981/82 3475 - - 81 19 -

1982/83 1726 Not available

Thimbirigaswewa (5.7 ha)

1979/80 9825 50 - - 50 -

1980/81 5000 98 - - 2 -1981/82 3684 33 33 33 - -

Maduwanwela (2.5 ha)

1980/81 3780 86 - 11 3 -

1981/82 2214 - - 77 - 23

1982/83 2129 40 27 13 20 -

Kudahatawewa (7 ha)

1979/80 9143 50 - - 50 -1980/81 4615 10 - - - -

1981/82 3000 33 33 33 - -

Table 6. Some details of the fish yields over four growiseasonal reservoirs (adopted from De Silva, 1988). SD ha; CP Culture period; T Tilapia; GC Grass carp; BCCommon carp; LD L. dussumieri.

kg ha-1could be achieved (Charkabarty and Samaranayake, and Kumarasiri, 1986; De Silva, 1988). To achieve these highavailability, selection of suitable seasonal reservoirs and pomanagement are essential. It is highly unlikely that fingerlinavailable in sufficient quantities to stock all seasonal reserv


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available in sufficient quantities to stock all seasonal reservsuch, it is important that wise use of the available seed stoca selection of reservoirs that are suitable for developing andbased fisheries.

Figure 5. Fish yields within a single culture cycle (1983-1reservoirs. Drawn from the data presented by Chandrasom(1986).

0

500

1000

1500

2000

2500

Weheragala

Bogas

wewa

Karametiwewa

Angunakola

wewa

Nika

wewa

Welap

ahala

Komaligama

Epitagoda

Tun

kama

Maha

wewa

M a d uw a

nw e l a

Reservoir

Yield(kg/ha)

Pushpalatha (2001) and Pushpalatha and Amarasinghe (2007studies of rural aquaculture in Sri Lanka for the production ponds and cages. In eight earthen ponds ranging in size fromof C. mrigala, C. carpio, L. dussumieri and L. rohitawere sgrowing period of 62-78 days, survival rates of fingerlings we8; P shpalatha 2001) P shpalatha (2001) also reported tha

practised in China (Li, 1988), production of bigger fingerlhelp to minimise mortality rates of juveniles. As fingerlinstocking in seasonal reservoirs during all the seasons, thesmall perennial reservoirs (Chandrasoma, 1992). Amarasithat in small (


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that in small (


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Regulatory processes

De Silva et al. (2005) have indicated that as the culture-basare community dependent, the final yield from individual rebe dependent on biological criteria such as the natural prodbodies and the hydrological regime but also on socioeconomthe degree of participation and cooperation within the comrelative easiness of marketing the produce.

Small village reservoirs come under the jurisdiction of the DAgrarian Services, which establishes a village farmers organreservoir. This farmers organisation is responsible for day-tmanagement. In the 1980s, the liaison between the DepartmServices and the Ministry of Fisheries has improved. Since ththe liaison between the Department of Agrarian Services anFisheries in 1980s, a well-structured institutional link has bebetween the National Aquaculture Development Authority oDepartment of Agrarian Services through which the field-levconsiderably facilitated (Figure 7). In fact, theAgrarian Dev46of 2000 provides legal provision for the establishment of institution, farmers organisation the mandate of within whfisheries and aquaculture development whenever the farmeto adopt it. In most seasonal reservoirs, farmers organisatioaquaculture committees. These committees are responsibleof culture-based fisheries. A proportion of the profit from thfisheries is utilised for improvement of reservoir such as streearthen bund so that there is a strong relationship betweencommittee and the farmers organisation.

The reservoir beds need to be prepared in most seasonal resstocking Remo al of impediments to fishing s ch as s bmer

seine nets for harvesting stocked fish. Members of the aqare actively involved in these labour-intensive activities.have experienced that in some reservoirs, farmers do notuntil the onset of harvesting because presence of macropprevents poaching of stocked fish.


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prevents poaching of stocked fish.

The National Aquaculture Development Authority of Sri Lextension activities pertaining to inland fisheries and aquextension staff have been appointed in place of the formwhose major responsibility is technology transfer, rather regulation. The enabling policy, legislative environment aempower communities are positive aspects for realising tbased fisheries development in village reservoirs.

Figure 7. Institutional links associated with the culturevillage reservoirs of Sri Lanka.

Agrarian Services

Department

NatonalAquaculture

Development

Authority

Regional

Extension

Centres

Fish Breeding

Centres

Divisional Officers RAEOs Aquaculturists

ARDAs AEOs

Issuing Aquaculture

Licenses

Seed Supply; Technical

Know-how

can be used to determine the reservoir area with a great pret al., 2005). This is of particular importance due to the readetermination of the reservoir area accurately is crucial forbased fisheries and that the available information on reservdatabases is largely underestimated as they were based on


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g y yfrom aerial photographs.

In view of the large number of seasonal reservoirs in Sri Lanto rank the suitability of them for development of culture-bTo develop a suitable ranking system or scale, aspects such chemical, biological, catchment and hydrological characterbodies, as well as socioeconomic aspects need to be taken iAccordingly, De Silva et al. (2005) have performed a prelimidevelop a ranking system to determine the suitability of 14 reservoirs in southern Sri Lanka. The ranking was achieved uinformation systems and analytic hierarchy process. The latheterogeneous factors to be equated to a common denominThematic layers of water quality, catchment characteristicsaspects and socioeconomic factors corresponding to each ofreservoirs studies were evaluated using the scores that wereto the weighted linear combination. The final weightings foreservoirs indicated that none of the reservoirs could be conone reservoir was considered as excellent, six reservoirs was fair and the remaining seven reservoirs were considereresults indicated the possibility of developing such a rankingresearch is presently being carried out more extensively in fidistricts of Sri Lanka.

Figure 8. Relationship between fish yield and stocking dereservoirs (Wijenayake, unpublished).

2000

1500

y = -0.0001x2+ 0

R2= 0.

Summary and conclusions

The reservoir fishery in Sri Lanka is very productive and isource of animal protein for rural communities. It is one best documented in tropical Asia. The stock assessment p


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p passessing the fisheries of Sri Lankan reservoirs enabled idfishing strategies. Potential fish production can be estimaland-use characteristics, which can be quantified by GIS mthe fish yield and fishing intensity are linearly related in of Sri Lanka the number of boats to be employed in eachdetermined using this relationship on the basis of estimaproduction. Length-based fish stock assessment methodothe optimal size of first capture of the two major cichlid total length. This corresponds to the stretched gillnet medetermined from gillnet selectivity studies.

Small cyprinids are abundant in perennial reservoirs of Srexploited mainly due to poor consumer preference. Gillntargeting cichlids also make it difficult to catch small sizethese small sized cyprinids can be differentially exploitedjuvenile cichlids. Due to high fishery potential of these cygillnet fishery can be introduced to exploit small cyprinid

Except in a few reservoirs where fingerlings of Indian majintensively stocked in 1980s, stocked exotic carps did notin majority of reservoirs. There has been a recent tendenreservoirs stock fish fingerlings using the funds raised for outcomes of such stocking regimes need to be evaluated

In Udawalawe reservoir, Indian major carps (mainly CatlaLabeo dussumieriform a significant portion of the landinrainy seasons. According to the information gathered fromIndian carps attached to submerged macrophytes could bareas of the reservoir. This evidence suggests that self-reof Indian major carps have been established in the Walawon the reprod cti e biolog of Indian major carps in Sri L

detrimental effects on capture fisheries. Also there has beeemphasis on the need of fisheries management in an ecosysof the fact that the fisheries have a direct impact on the ecalso impacted by other human activities (Garcia et al., 2003fisheries in seasonal reservoirs of Sri Lanka however, involve


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inputs especially due to the reason that supplementary feedbeing water bodies which completely dry-up during some moseasonal reservoirs do not harbour rich indigenous fish commother hand, under the inland fisheries development plan in culture of fish fry to fingerling in perennial reservoirs is promthat this aquaculture strategy will produce part of the fingefurthering the development of culture-based fisheries in sea

For the management of reservoir fishery of Sri Lanka, it is imcommunities be made active partners in decision the makinevidence is found from reservoirs of Sri Lanka that scientificbe collected through the active participation of fishing comby Ticheler et al. (1998) and Neis et al. (1999) for comparabother parts of the world. A co-management procedure in whadministration authority (i.e., Ministry of Fisheries) and fishshare the responsibilities of making decisions for fishery res(Berkes, 1994; Pomeroy, 1995; Sen and Raajaer-Nielsen, 199introduced for effective management of the reservoir fisher

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