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  1. Characteristics, structure and resources of the sector
    1. Summary
    2. History and general overview
    3. Human resources
    4. Farming systems distribution and characteristics
    5. Cultured species
    6. Practices/systems of culture
  2. Sector performance
    1. Production
    2. Market and trade
    3. Contribution to the economy
  3. Promotion and management of the sector
    1. The institutional framework
    2. The governing regulations
    3. Applied research, education and training
  1. Trends, issues and development
    1. References
      1. Bibliography
      2. Related links
    Characteristics, structure and resources of the sector
    Summary
    Despite its large fresh and brackishwater resources Sri Lanka does not have a tradition of aquaculture and only marine shrimp aquaculture and ornamental fish culture have been developed to any extent. Sri Lanka has a low number of indigenous freshwater fish plus another 18 exotic species, among the introduced species, three major Chinese carps, namely grass carp (Ctenopharyngodon idellus ), silver carp (Hypophthalmichthys molitrix ) and bighead carp (Aristichthys nobilis ) and three major Indian carps, catla (Catla catla ), rohu (Labeo rohita ) and mrigal (Cirrhinus mrigala ) are of particular importance to freshwater aquaculture. Despite the availability of 112 edible brackishwater species only one marine shrimp is utilised in coastal aquaculture.

    In more recent years, the export of farmed shrimp has contributed over 50 percent of the total export earnings from the fisheries sector with ornamental fish production contributing another 11 percent. Current production from seasonal village tank culture contributes only 1.2 percent to national inland freshwater fish production, however, due to its perceived potential, it has been identified as an activity which can boost domestic freshwater fish production and enhance the livelihoods of the rural poor. Other sectors of aquaculture which have been identified for development and promotion include coastal finfish culture, sea weed culture and freshwater prawn culture.

    The key institutions related to the development and regulation of aquaculture under the Ministry of Fisheries and Ocean Resources are the Department of Aquatic Resources, the National Aquatic Resources Research and Development Agency (NARA) and the National Aquaculture Development Authority (NAQDA). NARA is the principal national research institution mandated to carryout research and development activities in the field of aquatic resources while NAQDA is entrusted with the activities of developing commercial aquaculture and extension activities. The National Institute of Fisheries and Nautical Engineering (NIFNE) is in charge of education and training. The Aquatic Resources Development and Quality Improvement Project, assisted by the Asian Development Bank, commenced in mid 2002 to address the components of the Aquaculture Inland Fisheries Development in the National Fisheries Development Action Plan. The rationale for the implementation of the project is to utilise the vast potential for the development of inland aquatic resources to ensure food security and uplift the socio-economic status of the rural populations in non-coastal areas as means to reduce poverty.
    History and general overview
    Sri Lanka does not have a tradition of aquaculture, despite the large freshwater and brackishwater resources available in the country, there was virtually no aquaculture carried until the beginning of 1980. Since that time fish culture in seasonal village tanks, marine shrimp culture in coastal earthen ponds and live ornamental fish exports have reached commercial dimensions while other attempted methods such as fish culture in brackishwater ponds, cage culture, mollusc and seaweed culture are yet to be developed.

    Freshwater fish culture in seasonal village tanks was initiated in 1979 by the Inland Fisheries Division of the Ministry of Fisheries with 23 tanks in the country's dry zone and from 1979 onwards the polyculture of fish using tilapia and carp has been carried out. In the early 1980s a number of small-scale entrepreneurs and a few multinational companies responding to the incentives offered by the government, including duty free imports of inputs, embarked on the culture of giant tiger prawn (Penaeus monodon ) in coastal ponds. In the late 1990s the commercial growing of the Indo-Pacific swamp crab (Scylla serrata ) in plasticised wire mesh cages began in coastal lagoons.

    In contrast, the ornamental fish industry in Sri Lanka has a long history and was started with household based small-scale outlets in cities. In the early 1930s, there were several small-scale importers, breeders and hobbyists in Sri Lanka; a commercial aquarium was started in 1952 in Colombo, the capital of Sri Lanka. This industry was commercialised by a few entrepreneurs about 50 years ago and it has now developed into a thriving industry affording profits and employment for many. Ornamental fish culture is carried out mainly in cement tanks.
    Human resources
    The employment generated from seasonal village tank fish culture is estimated to be around 6 000 of which 13 percent are women (Siriwardena and Jayakody, 2003). It was estimated in 1999 that the shrimp aquaculture industry provided approximately 40 000 jobs both directly and indirectly, which represents 11 percent of the total employment in the fisheries sector (Siriwardena, 1999). However, the previously estimated figure of 20 000 directly employed as a result of shrimp farming has currently been reduced to 8 000 (Hettiarachchi, 2000) due to the repeated occurrence of disease within the shrimp industry. The participation of women in shrimp aquaculture is around 5 percent of the total workforce (Siriwardena and Jayakody, 2003).

    An estimated 2 500 people are engaged in the production and breeding of ornamental fish (Haputanthri et al ., 2001); of which around 30 percent are estimated to be women, however, no thorough survey has been carried out to this effect (Siriwardena and Jayakody, 2003).
    Farming systems distribution and characteristics
    Seasonal village tanks

    Seasonal village tanks are mainly found distributed across the dry zone of Sri Lanka, currently an area of 667 ha of seasonal village tanks is utilised for fish culture (Siriwardena and Jayakody, 2003), this is only 10 percent of the total potential area for development. The management measures adopted in seasonal village tank culture consist largely of stocking with juveniles and their subsequent harvesting; supplementary feeding of the fish is not practiced. The stocking rates practiced range between 2 000 to 3 000 fingerlings producing 750 to 1 000 kg/ha/annum, the average water area of seasonal tanks under culture varies from 4.5 ha to 7 ha. It has been demonstrated that by the addition of inputs such as fertiliser and feed and employing higher stocking rates yields of up to 2 000 kg/ha from these water bodies can be attained.

    Shrimp aquaculture

    The current shrimp aquaculture industry in Sri Lanka is concentrated in the north western coastal belt covering a farm area of more than 4 500 ha with 70 hatcheries, of the total farm area the ponds themselves occupy an area of around 3 000 ha. There are a total of 1 344 farm establishments, of which 47.7 percent are considered to be establishments operating without proper licences (Siriwardena, 2001b). On the eastern coast in Batticaloa District, where shrimp farming in Sri Lanka first began in the late 1970s but was abandoned due to civil unrest, operations have recommenced in recent years. Over 60 small farms with an average farm area of between 1–2 ha were in operation at the end of 2002, with a total pond area of 155 ha.

    Shrimp aquaculture was practiced using an open system of operation in earthen ponds until white spot virus in 1996 and yellow head virus in 1998 caused serious economic losses in the industry. The production cycle is between 140 to 160 days with 1.8 culture cycles completed per year. Following these outbreaks of disease, the industry developed closed and semi-closed production systems as well as fully recirculated systems. The stocking densities employed prior to the disease outbreaks ranged between 20 to 30 post-larvae per m2 , following the disease outbreaks the industry reduced the stocking densities to below 15 post-larvae per m2 . Feed the main input in the shrimp farming sector is imported, as are paddle wheels, pumps and generators. Feed contributes 50–60 percent to the total cost of production of shrimps.

    Crab fattening

    The commercial farm units use different sizes of plastic coated wire mesh cages for crab fattening, but the most commonly used cages are 2m x 2m x 0.5–0.75 m for easy handling (Jayamanne, 2003). The average stocking density employed by the farmers is 10-15 kg of water crabs/m2 . Bivalves, prawn heads, slaughterhouse waste and trash fish are the basic feed used in crab fattening.

    Ornamental fish culture

    Ornamental fish culture is widely spread in Sri Lanka but the breeders and exporters are mainly limited to the Colombo area. Grow-out facilities tend to be cement cubicles, glass aquaria and earthen ponds, with the breeders practicing simple natural spawning techniques to breed freshwater ornamental fish. The most commonly used feed supplements in the sector are farm-made feeds, shrimp and poultry feeds.
    Cultured species
    Sri Lanka has relatively limited number of freshwater fish species with 111 recorded species (Pethiyagoda, 1991). The 80 species of indigenous freshwater fish belonging to 11 families consist of riverine marsh dwelling species and lack truly lacustrine species (Fernando and Indrasena, 1969), twenty seven species are endemic and the Cyprinidae constitute the most commonly represented family (De Silva, 1988). In contrast to its poor indigenous fauna, there are 18 exotic species, including one estuarine transplant, the sea trout (Salmo trutta ), that have been introduced into Sri Lanka (Chandrasoma, 1983). It is generally accepted that a commercial inland fishery only developed in Sri Lanka after the introduction of the exotic Mozambique tilapia (Oreochromis mossambicus ).

    Among the introduced species, the following three major Chinese carps and three major Indian carps are of particular importance in aquaculture.
    1. Chinese carps: grass carp (Ctenopharyngodon idellus ), silver carp (Hypophthalmichthys molitrix ) and bighead carp (Aristichthys nobilis ).
    2. Indian carps: catla (Catla catla ), rohu (Labeo rohita ) and mrigal (Cirrhinus mrigala ).
    Among the indigenous freshwater fish, 54 species are regularly exported and presently form the mainstay of the ornamental fish export industry. Of the 27 endemic freshwater species 21 have ornamental value.

    Pillai (1965) has recorded a total of 112 edible species from the brackishwaters of Sri Lanka: 65 percent migrants from the sea, 30 percent strictly brackishwater species and 5 percent freshwater. Of the 112 species, only one, the milkfish (Chanos chanos ) and the giant tiger prawn (Penaeus monodon ) are used in coastal aquaculture.
    Practices/systems of culture
    Development of seasonal village tank culture has been identified for priority aquaculture development by the National Fisheries Development Plan to boost domestic freshwater fish production. In contrast, the shrimp farming industry is a valuable foreign exchange earner and it has been earmarked for further expansion as it comprises the largest quantity of any export product and earns the highest amount of foreign exchange. Crab fattening is also gaining attention as an export orientated activity.

    Brackishwater fish culture, coastal fish culture in net enclosures, sea weed culture and mussel mariculture have not yet reached commercial dimensions. Fifty eight farms were recorded as engaged in milkfish culture in 1987 with a total water area of 3.70 ha and a production of 6.6 tonnes, valued at SLR 92 000 (Siriwardena, 1989), however, despite substantial yields of milkfish from some experimental pens (Siriwardena, 1986); it has not fully developed to a commercial scale due to marginal returns.

    The production of South American rock mussel (Perna perna ), is being carried out by a few farmers in western and southern regions and production of the seaweed Gracilaria edulis is also providing some promising results.
    Sector performance
    Production
    The graph below shows total aquaculture production in Sri Lanka according to FAO statistics:
     

    Reported aquaculture production in Sri Lanka (from 1950)
    (FAO Fishery Statistic)

    (Source: FAO Fishery Statistics, Aquaculture production)

    Market and trade
    Freshwater fish raised in seasonal tanks are simply sold at the local fairs known as 'pola' by the farmers themselves or sold to an intermediate to sell at local markets. In contrast more than 90 percent of the farmed shrimps are exported and sold directly from the producer to the processor / exporter, the balance of production is sold at the local market outlets.

    An increase in ornamental fish exports has been observed following technological developments in the breeding and rearing of more than 46 species of freshwater ornamental fish. The export of marine ornamental fish, however, is totally dependent on the capture of wild stocks and currently over 200 marine species belonging to 40 families are exported. Increasing pressure on marine ornamental wild fish stocks has consequently led to the depletion of several wild fish populations; as a result government has prohibited or restricted certain marine and freshwater fish species from export.

    The main Sri Lankan export market for farmed shrimps is Japan followed by the United States of America and the European Union countries. The European Union market takes mainly small shrimps in both head-on and tail only products. The Fish Product (Export) Regulations of 1998 and Aquaculture (Monitoring of Residues) Regulations of 2000 require inspection and certification of compliance to these regulations by the licensee for each export consignment. A special emphasis has been placed on monitoring to ensure there are no residues of antibiotics as per European Union's guidelines and requirements. The competent authority for issuing residue free certificates is the Director General of the Department of Aquatic Resources.

    Sri Lanka exports ornamental fish to more than 18 destinations, the 10 main export markets, based on the value of ornamental fish exported are: Germany, France, United Kingdom, Belgium, Netherlands, Spain, Switzerland, Japan, United States of America and Italy. According to Customs statistics, there are 66 large and small-scale ornamental fish exporters in Sri Lanka, of which 10 exporters have exported ornamental fish valued at over SLR 10 million per annum.

    Documentation certifying the bacterial types and counts, especially for Vibrio cholerae , is requested by certain buyers prior to export of ornamental fish, this is to prevent the spread of disease through trans-boundary movements of live aquatic animals. The health certification for export of live fish is issued by the Department of Animal Health and Production in compliance with the infectious pathogens and diseases listed by the Network of Aquaculture Centres in Asia-Pacific (NACA) and the Office International des Epizooties (OIE).
    Contribution to the economy
    Inland freshwater fish are supplied mainly from the capture fisheries in reservoirs, seasonal village tank culture and freshwater pond fish culture have not impacted significantly either on the volume of inland fish production and income nor in its ability to enhance livelihoods. Due to the lack of village level organisation with the ability to manage seasonal tanks and community/private sector participation in seed supply, the development of seasonal tank culture and freshwater pond culture collapsed following the withdrawal of state patronage for aquaculture in 1990, this support was, however, reinstated in 1994.

    Current productivity of seasonal village tank culture is 0.46 tonnes per ha and contributes 330 tonnes to the total inland freshwater fish production, this is equivalent to only a 1.2 percent contribution to the national inland freshwater fish production. Nevertheless, due to its potential to enhance livelihoods of the rural poor it has been identified as an area for support.

    Over the last decade earnings from foreign income as a result of shrimp farming ranged between SLR 551.70 million in 1992 and SLR 4 000 million in 1998. In more recent years, the export of farmed shrimp has contributed over 50 percent of the total export earnings from the fisheries sector. In absolute terms, the industry has consistently netted well over SLR 2 000 million in foreign exchange since 1995, moreover, shrimp farming has contributed towards the development of support industries such as lime outlets/producers, fibreglass manufacturers, feed outlets, machinery supply and repair facilities, hardware stores and laboratories.

    A considerable amount of foreign exchange is earned through the export of ornamental fish. In 2002 this was SLR 680 million, which represents around 11 percent of the total export earnings from fish and fishery products. The contribution by ornamental fish exports from Sri Lanka, in monetary terms, amounts to just over 1 percent of the value of the global trade in ornamentals.

    Development of aquaculture in Sri Lanka has mainly targeted potential export commodities with the opportunities available to the rural poor coming in the form of employment, mainly as labourers. When compared with shrimp aquaculture, ornamental fish breeding and culture has more impact on people's livelihoods as this sector has developed as a cottage industry across Sri Lanka, mainly in the form of on growers and small-scale breeders.
    Promotion and management of the sector
    The institutional framework
    The Ministry of Fisheries and Ocean Resources (MFOR) holds the overall responsibility for aquaculture activity in Sri Lanka. Within the Ministry there are three departments and agencies with specific responsibilities relating to aquaculture spread across the divisions under their control, namely:
    1. Department of Fisheries and Aquatic Resources (DFAR).
    2. National Aquatic Resources Research and Development Agency (NARA).
    3. National Aquaculture Development Authority (NAQDA) under the control of which is the Inland Aquaculture Development Division (IAD) and the Coastal Aquaculture Development Division (CAD).
    The governing regulations
    The Fisheries and Aquatic Resources Act (1996) addresses the management, regulation, conservation and development of fisheries and aquatic resources in Sri Lanka. Part VI of the Act addresses aquaculture. Part X of the Act grants the Minister of Fisheries and Aquatic Resources general power to make regulations with regard to all matters stated in the Act, including the management and regulation of aquaculture. Several regulations have been adopted under the Act, which have an impact on aquaculture and aquaculture products.

    The National Aquaculture Development Authority of Sri Lanka Act (1998) establishes the National Aquaculture Development Authority and regulates its functioning and constitution. The Authority has general policy responsibility for the development of the aquaculture sector in Sri Lanka.

    For more information on aquaculture legislation in Sri Lanka please click on the following link:
    National Aquaculture Legislation Overview – Sri-Lanka
    Applied research, education and training
    The National Aquatic Resources Research and Development Agency (NARA) is the principal national research institution mandated to carryout research and development activities in the field of aquatic resources while the National Aquaculture Development Authority (NAQDA) is entrusted with activities in developing commercial aquaculture and extension. The Research priority settings are mainly decided on depending on national requirements. The research is oriented towards meeting the targets set in the National Fisheries Development Plan, which is the policy document of the fisheries sector. Industrial problems, institute-industry partnerships and regional trends are also considered when prioritising research. More recently rural aquaculture development has received priority as one of the measures to enhance livelihoods and reduce poverty among the rural poor. Problems for research are identified through farmer/community consultations and feed back received from extension activities in addition to areas high lighted through scientific forums. In addition to NARA and NAQDA several universities engage in aquaculture research, although mainly academic in nature.

    Currently there are several associations active in the aquaculture sector:
    1. Prawn Farmers and Exporters Association.
    2. Shrimp Breeders Association.
    3. Local small-scale shrimp farmers associations.
    4. Ornamental Fish Breeders and Exporters Association.
    With respect to aquaculture research there is very little partnership between the institutions and industry, despite research having been offered to the institutions from the aquaculture sector. NARA has accorded high priority for farmer/community participatory research more than for institutionalised research, currently NARA carries out on-farm participatory research in the areas of integrated aquaculture in rural areas, freshwater prawn breeding and culture, disease diagnosis, control and prevention in ornamental as well as in shrimp aquaculture, management of fish culture in seasonal village tanks, farmer made aqua-feeds, community participation in fry to fingerling rearing in reservoirs, fish breeding technology and the promotion of good management practices.
    Trends, issues and development
    A policy decision was taken in July 1990 to withdraw state patronage from inland fisheries and aquaculture and hence the proposals contained in the National Fisheries Development Plan for this sub-sector were dropped, except for those relating to shrimp culture and ornamental fish breeding and culture where operations were entirely in the hands of the private sector. However, a World Bank Study estimated that in 1990 the inland fisheries and aquaculture sector was contributing US$ 24 million per year to the rural economy of Sri Lanka. The period immediately following the removal of patronage i.e. between 1990–1994 shows a sharp decline in inland fisheries and aquaculture production to 12 000 tonnes in 1994. Termination of the supply of seed, as well as the extension and technical support provided by the government were the major causes of this decline.

    The government in 1994 announced a reinstatement of the policy to develop inland fisheries and aquaculture covering a 10 year period from 2002–2012. A major component in the Action Plan of the Ministry of Fisheries and Ocean Resources for 2002–2010 relates to the Aquaculture and Inland Fisheries Development Plan.

    The Aquatic Resources Development and Quality Improvement Project, assisted by the Asian Development Bank, commenced in mid 2002 to address the component on Aquaculture and Inland Fisheries Development. The rationale for the implementation of the project is to utilise the country's vast potential for the development of inland aquatic resources to ensure food security and uplift the socio-economic status of the rural populations in non-coastal areas as a means to reduce poverty.

    Despite the potential of seasonal village tanks to boost the domestic inland freshwater fish production, development has progressed at a slow rate mainly due to a shortage of juvenile fish to stock the seasonal tanks. There is a need to strengthen the community participation in fry to fingerling rearing operations to meet this demand for juveniles, in this regard, it is recommended that there is the establishment of seasonal tank management groups consisting of farmers, mini-hatchery operators, juvenile fish producers and a technical support unit to manage seasonal tanks.

    In the coastal shrimp aquaculture sector the management of outbreaks of disease has become the main issue. Uncontrolled expansion exceeding carrying capacity as well as water quality deterioration have been the main causes for disease outbreaks which have resulted in a production loss valued at up to one SLR billion in foreign income (Siriwardena, 2001a).

    The rapid expansion of the shrimp farming industry over the past decade has contributed to the environmental problems together with conflicts between stakeholders as well as the recent disease outbreaks. The following resources have been or thought to have been affected by shrimp farming operations (Siriwardena, 2001b): ecologically sensitive habitats, wildlife, agricultural land, wild fish populations and ground water. According to estimates made by the Ministry of Fisheries of the Northwestern Province, more than 1 200 ha of mangroves have been subjected to total destruction as a result of shrimp farming activity. Despite recommendations made to declare the northern part of Mundal Lagoon as well as its southern mudflats as sanctuaries (De Silva and Jacobson, 1995), a significant proportion of these areas have been developed for shrimp farming.

    The main agricultural lands that have been affected in the north western coastal belt due to shrimp farming are rice paddies and coconut production land. The attractive profits from shrimp farming do not justify the conversion of these agricultural lands into shrimp ponds.

    According to the Ministry of Fisheries in the Northwestern Province the farm area utilising ground water for shrimp aquaculture is 720 ha. Based on the actual water area under culture with a 25 percent renewal of freshwater for dilution, the ground water demand is estimated to be around 1.0 million m3 /dilution (Siriwardena, 2001b). As a result, due to lack of adequate supplies of freshwater for drinking and other uses in this area, shrimp aquaculture has led to a degree of user conflict. The likely cause for the reported fish kills in the Dutch Canal, which is the main source of water for the industry, were the high recorded levels of sulphides, un-ionised ammonia and nitrite (Corea, et al ., 1995).

    In addition, the following issues have been raised by the village communities living in shrimp farming areas (Siriwardena, 1999).
    1. The community has greater rights to state land than the 'intruding' non-resident shrimp farmers.
    2. Salt water intrusion into wells and agricultural lands.
    3. Clearance of mangroves affecting local community who make sustainable use of this resource.
    4. Loss of grazing land affecting livestock.
    5. No provision for anticipated employment opportunities for the local community.
    6. Obstruction of traditional access routes to fishing grounds.
    7. Loss of ground water due to extraction of large volumes of the latter.
    References
    Bibliography
    FAO . 2005 . Aquaculture production, 2003. Year book of Fishery Statistics - Vol.96/2. Food and Agriculture organization of the United Nations, Rome, Italy.
    Corea, A.S.L.E. , Jayasinghe, J.M.P.K. , Ekaratne, S.U.K. & Johnstone, R.W. 1995 . Environmental impact of prawn farming on Dutch Canal: The main water source for the prawn culture industry in Sri Lanka. AMBIO, 24:423-427.
    Costa, H.H. & De Silva, S.S. 1995 . Limnological research and training in Sri Lanka: State of art and future needs. In: B. Gopal and R.G. Wetzel (eds.) Limnology in developing countries. Pp. 63-203, International Association for Limnology.
    Dayaratne, P. , Linden, O. & De Silva, R. 1997 . The Puttalam/Mundel estuarine system and associated coastal waters. A report on environmental degradation, resources management issues and options for their solution. 98 pp.
    De Silva, S.S. 1988 . Reservoirs of Sri Lanka and their fisheries. FAO Fisheries Technical Paper No. 298: 128 pp.
    De Silva, R.I. & Jacobson, S. 1995 . Mundel Lake (Sri Lanka): An important habitat for migratory shore birds. Published by the Wlidlife and Nature Protection Society of Sri Lanka.
    Fernando, C.H. & Indrasena. 1969 . The fresh water fisheries of Ceylon. Bull. Fish.Res. Stn. Ceylon, 20:101-134.
    Haputanthri, S. , Perera, P.A.J.C. & Vidanage, S.P. 2001 . Development of ornamental fish production and culture for increased export earnings and employment opportunities. Unpublished report of NARA, Colombo 15, Sri Lanka. 49 pp.
    Jayamanne, S.C. 2003 . A manual for crab fattening. National Aquatic Resources Research and Development Agency, Colombo, Sri Lanka. 12 pp.
    Pethiyagoda, R. 1991 . Fresh water fishes of Sri Lanka. Wildlife Heritage Trust, Colombo, Sri Lanka.
    Pillai, T.G. 1965 . Brackish water fishery resources. Bull. Fish. Res. Stn. Ceylon, 18:5-85.
    Siriwardena, P.P.G.S.N. 1986 . Milkfish pen culture in Sri Lankan lagoons. In J.L. Maclean, L.B. Dizon and L.V. Hosillos (eds). Proc. The First Asian Fisheries forum, Asian Fisheries Society, Manila. Philippines: pp. 89-92.
    Siriwardena, P.P.G.S.N. 1989 . Survey on aquaculture - Phase II (Sri Lanka): A descriptive report. Asian Productivity Organisation, Tokyo, Japan.
    Siriwardena, P.P.G.S.N. 1999 . Shrimp culture in Sri Lanka: The benefits, problems and constraints associated with the development and management and responses to address problems. Bangkok FAO Technical Consultation on Policies for Sustainable Shrimp Culture. Pp. 99-110, FAO Fisheries Report No. 572.
    Siriwardena, P.P.G.S.N. 2001 a. Management strategies for major diseases in shrimp aquaculture in Sri Lanka. In R. Subasinghe, R. Arthur, M.J. Phillips and M. Reantaso (eds.) , "Thematic Review on Management Strategies for Major Diseases in Shrimp Aquaculture", Proceedings of a workshop held in Cebu, Philippines, 28-30 November 1999. WB/NACA/WWF/FAO Consortium Programme on Shrimp Farming and the Environment.
    Siriwardena, P.P.G.S.N. 2001 b. Shrimp farming and associated problems. In N. Farmer (ed.). Report of the Workshop on Effective Management for Biodiversity Conservation in Sri Lankan Coastal Wetlands: Muturaawela Marsh, Negombo Lagoon and Chilaw Lagoon (MMNCL), Centre for the Economics and Management of Aquatic Resources, University of Portsmouth. Report No. 55: pp. 55-66.
    Siriwardena, P.P.G.S.N. & Jayakody, D.S. 2003 . Aquaculture technologies and fishing practices of Sri Lanka. Report submitted to ICLARM on the Strategies and options for increasing and sustaining fisheries and aquaculture production to benefit poor households in Asia, ADB - RETA 5945 Project. Sri Lanka (in press).
    Wanninayake, W.M.T.B. 1998 . Raft culture of brown mussel, Perna perna, in Rumassala Bay, Sri Lanka. A manual on culture. National Aquatic Resources Research and Development Agency, Colombo, Sri Lanka. Pp. 12.
    Wijesekera, R.G.S. Techno-economical evaluation of freshwater ornamental fish industry in Sri Lanka. M.Sc. Thesis, Asian Institute of Technology Bangkok, Thailand, pp. 112 (Unpublished thesis).
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