Coastal Aquaculture Zoning in Sri Lanka

Table of Contents



based on the work of

Charles L. Angell
FAO Consultant on Coastal Aquaculture


The designations employed and the presentation of the material in this document do not imply the expression of any opinion whatsoever on the part of the Food and Agriculture Organization of the United Nations concerning the legal status of any country, territory, city or area of its authorities, or concerning the delimitation of its frontiers or boundaries.

The Food and Agriculture Organization is greatly indebted to the organizations and individuals who assisted in the implementation of the project by providing information, advice and facilities.

This electronic document has been scanned using optical character recognition (OCR) software and careful manual recorrection. Even if the quality of digitalisation is high, the FAO declines all responsibility for any discrepancies that may exist between the present document and its original printed version.

Table of Contents


1. Introduction

1.1 The objective of zoning
1.2 The need for zoning coastal aquaculture

2. The zoning matrix

2.1 Matrix species

2.1.1 Penaeus monodon
2.1.2 Penaeus indicus
2.1.3 Scylla spp.
2.1.4 Artemia
2.1.5 Crassostrea spp.
2.1.6 Perna spp.
2.1.7 Gracilaria spp.
2.1.8 Holutherioidea
2.1.9 Hybrid Tilapia
2.1.10 Marine fin fish

2.2 Matrix criteria
2.3 Ranking parameters

2.3.1 Elevation
2.3.2 Soil pH
2.3.3 Soil texture
2.3.4 Vegetation, land use and user conflicts
2.3.5 Access to infrastructure
2.3.6 Salinity
2.3.7 Water quality criteria

3. Zoning for coastal aquaculture

3.1 Preparation of base maps and overlays
3.2 Field surveys
3.3 GIS data base revision
3.4 Publication and dissemination
3.5 Incorporation into CZM regulations

4. Zoning for species and technologies

4.1 Penaeus spp.
4.2 Scylla spp.
4.3 Artemia
4.4 Crassostrea spp.
4.5 Perna spp.
4.6 Gracilaria spp.
4.7 Holutherioidea
4.8 Hybrid tilapia
4.9 Marine and brackishwater fin fish

5. Zoning for hatcheries

6. Culture based fisheries

7. List of references


Annex 1 List of Survey Department maps of the coastal zone of Sri Lanka
Annex 2 Field data collection form
Annex 3 FAO code of good practice for aquaculture


Shrimp farming is the only commercial aquaculture industry in the coastal zone of Sri Lanka, but other species have potential. Much of the shrimp farming development has occurred without regulation and due concern for the environment. Although a few well capitalized farms are properly sited and managed by technically competent staff, a large number of smaller farms find themselves in the opposite situation. There has been loss of mangrove habitat, outbreaks of shrimp diseases and poor production as a result.

Zoning for coastal aquaculture development can avoid many of the problems that confront the shrimp farming industry in Sri Lanka. While development has occurred only in the Northwestern Province, the lagoons and bays of the eastern and northern coasts have the greatest potential for future development of coastal aquaculture. On the other hand, possibilities are very limited on the southern coast. Many ideal sites can be found here for marine finfish hatcheries.

Species which are currently commercially cultured in Sri Lanka and other Indo-Pacific countries or have shown they have potential include Penaeus monodon, P. indicus, Scylla spp., Artemia, Crassostrea spp., Perna spp., Gracilaria spp., Holutherioidea, hybrid tilapia, and marine finfish (milkfish, sea bass, grouper, rabbitfish and sea bream).

Criteria were identified which impact the development of coastal aquaculture technology. These include elevation, soil pH and texture, vegetation and land use, user conflicts, access to infrastructure, salinity and water quality. The criteria were defined by subdividing them into parameters. The relative importance of each parameter was scored on a scale of 0 to 3. Zero is used to eliminate sensitive areas such as mangroves and wild life sanctuaries or wholly unsuitable sites. The score of each parameter is the product of the criteria by parameter rank.

Potential areas for coastal aquaculture zones have been identified on the basis of maps, current distribution of the industry, past studies and field observations. A detailed Geographic Informations Systems (GIS) data base will be established for each of these areas. The data base will be constructed using sources including coastal survey maps, soil maps, hydrological maps, navigation charts, past studies (both published and unpublished) and primary data collected by the survey team in the field. A study area has been identified in the Northwest Province in collaboration with the GIS consultant. The survey of the study area will encompass the coast line from the southern end of Chilaw Lake to Dutch Bay, Puttalam.

The zoning process incorporates a number of tasks, the first of which will be to digitize available maps and survey data. The base map will be drawn from coastal survey maps at a scale of 1:50,000. Individual overlays will be constructed for each parameter, depending on what data is available. Field surveys should be undertaken only after the first task has been completed and gaps in the data base have been identified. The GIS data base will then be revised based on the results of field surveys.

The publication and dissemination of the coastal aquaculture zoning plan and its incorporation into coastal zone management regulations should be the output of the zoning process.

This document represents the technical report of the coastal aquaculture component of the TCP project. As such, it incorporates the interim report entitled Methods for establishing coastal aquaculture zones in Sri Lanka, TCP/SRL/6712(A) Field Document No. 1.


The author gratefully acknowledges the assistance and collaboration of the Ministry of Fisheries without whose support the mission could not have been completed. The enthusiastic participation and dedication of the staff of the Planning and Information Unit (PIU), NARA was much appreciated. NARA scientists gave freely of their time and provided invaluable insights into the current aquaculture situation in the country. Thanks are also due to the FAO Representative for Sri Lanka and the Maldives and his staff and to the UNOPS staff in Jaffna for assisting in all aspects of this consultant's mission to Jaffna.

1. Introduction

1.1 The objective of zoning
1.2 The need for zoning coastal aquaculture

Sri Lanka has a coastline of 1561 km encompassing lagoons, estuaries, bays and fringing reefs. Fisheries play a central role in supplying about 65% of the animal protein consumed by the populace. It also generates foreign exchange, mainly through the export of captured and farmed shrimp.

Lagoons and sheltered bays are common along the coast and are potential sites for aquaculture development of a variety of species. Coastal habitats have been classified into 7 categories. The district-wise areas of these habitats are shown in Table 1.

Table 1. Areas in ha of principle coastal habitats by province.



Salt marshes


Beaches, barrier beaches, spits

Lagoons, basin estuaries

Other water bodies

Fresh water Marshes





































































































Total Area








The areas of interest for coastal aquaculture include lagoons and mangroves. Comparisons among districts for these habitats are depicted in Figs. 1 and 2. The distribution of mangroves parallels that of lagoons, as would be expected.

Fig. 1 Mangrove area in ha by district

Fig. 2 Area of lagoons by district

It is clear from the above that the majority of habitat suitable for coastal aquaculture development lies on the eastern and northern coasts.

A brief field survey of the western and southern coasts from Colombo to Hambantota indicates this portion of the coast has very little potential for coastal aquaculture. Detailed studies by the National Aquatic Resources Agency (NARA) show that small areas adjacent to lagoons along the south coast are suitable for shrimp culture. An area of about 363 ha at Koholankala, Hambantota has been identified as a potential site for shrimp culture and an Environmental Impact Assessment prepared. However, an elephant migration route cuts across the site. Furthermore, there is reportedly very strong local opposition to shrimp culture, which has halted the project in its initial stages.

Among the constraints confronting aquaculture development on the western and southern coasts are:


Colombo to Galle

Limited area of lagoons and embayments

Colombo to Galle

Use conflicts:


Hambantota to Yala N.P.


Galle to Hambantota


Tangalla to Hambantota


Tangalla to Hambantota

Commercial coastal aquaculture is a relatively new undertaking in Sri Lanka and is limited to the production of the tiger shrimp, Penaeus monodon. One of the earliest attempts at shrimp culture was sited in Batticaloa, but had to be abandoned because of the security situation. Other pioneer farms were located around Chilaw Lake. Today, farms are remarkably concentrated from Chilaw to Puttalam Lagoon. The nascent industry is confronting serious problems which bring into question its sustainability. Viral and bacterial diseases have heavily impacted production. Productivity has shown a clear decline since the industry started.

The problems confronting shrimp farmers are the direct result of siting on inappropriate soils and environmental overload. Many farms are located between Mundal Lake and Puttalam Lagoon. Their main source of water, the Dutch Canal, also receives shrimp farm effluent. The carrying capacity of the Canal is very limited by its low flushing rate. The Canal receives waste from agricultural and urban runoff in addition to the load put on it by shrimp farm effluent.

Inconsistent rainfall and reduction of freshwater runoff into Puttalam Lagoon have resulted in rising salinity, which is now beyond the optimum range for tiger shrimp. It is reported that some farms are drawing on ground water to try to control salinity. If this practice continues, the effect on freshwater supplies to local communities will be extremely negative:

The situation of the shrimp farming industry is a classic example of uncontrolled development with little or no regard for the environmental consequences. It is unlikely to be sustainable and the failure of many enterprises can be foreseen.

1.1 The objective of zoning

It is now widely recognized that the future of the aquaculture industry will be assured only if it is based on practices which ensure its sustainability. Five elements of sustainable development were given by Muir (1996), citing Jacobs, et al. (1987):

· Integration of conservation and development,
· Satisfaction of basic human needs,
· Achievement of equity and social justice,
· Provision for social self-determination and cultural diversity, and
· Maintenance of ecological integrity.

The incorporation of sustainability in development is perceived by Jacobs op. cit. as "a reaction against the laissez faire economic theory that considered living resources as free goods, external to the development process, essentially infinite and inexhaustible."

According to Pearce (1991) as quoted by Muir op. cit. most definitions suggest as core values:

· Futurity: a concern for the well being of future generations (inter-generational welfare)

· Equity: Concern for future generations should extend to equity for the present generation (intra-generational welfare),

· Environment: greater emphasis on the environment.

The FAO Code of Good Practice for Aquaculture (Annex 8.3) also reflects these concepts of sustainability. If these elements and their core values are accepted as the basis for sustainable development, then aquaculture development planning should incorporate them. Zoning, through GIS technology or other methods, is a first step in implementing policies which promote sustainable development. It does this by identifying areas which are environmentally suitable and excluding from development those which conflict with the elements of sustainable development.

1.2 The need for zoning coastal aquaculture

Haphazard development of aquaculture inevitably leads to environmental overload, conflict among user groups and serious economic losses to the industry. The uncontrolled expansion of shrimp farming in Sri Lanka is just one of many examples of the consequences of inappropriate siting, overcrowding and destruction of mangroves.

GIS technology gives the planner and developer the capacity to evaluate the interaction of a wide range of environmental and social factors which affect the potential of a region for aquaculture development. This complex of influences is integrated through a ranking and scoring system. Each factor is scored and mapped accordingly. The product of ranks are scores which identify zones where sustainable aquaculture can be developed.

Aquaculture development can be directed to suitable areas through a permitting process such as the Scoping Committees at the national and provincial levels. The developer and financial institutions can evaluate the feasibility of projects more readily.

2. The zoning matrix

2.1 Matrix species
2.2 Matrix criteria
2.3 Ranking parameters

A matrix of species and environmental criteria impacting their culture systems has been constructed (Table 2 at page 13). Only shrimp culture has developed as a commercially viable technology in Sri Lanka, but a number of other species have shown promise. Many are well suited to small scale production and could have a positive impact on the economies of small fisherfolk communities. Various criteria have been selected according to their impact on the technical feasibility of culture of the species included in the zoning matrix. Criteria are ranked according to their relative importance for each species. Criteria are further refined by parameters which usually indicate ranges.

2.1 Matrix species

2.1.1 Penaeus monodon
2.1.2 Penaeus indicus
2.1.3 Scylla spp.
2.1.4 Artemia
2.1.5 Crassostrea spp.
2.1.6 Perna spp.
2.1.7 Gracilaria spp.
2.1.8 Holutherioidea
2.1.9 Hybrid Tilapia
2.1.10 Marine fin fish

The species included in the matrix have been selected from a technical standpoint only. Although it may be technically possible to grow a species in the coastal zone of Sri Lanka, the special conditions which would favor commercial aquaculture may not be present. Zoning should take into account possibilities in the future, as well as present reality. The species included in the matrix are listed below.

There has been considerable experimental work with some of these species, such as oysters and seaweeds, which has indicated potential for development. Others will require further investigation and pilot field trials before commercial development can be undertaken. New species are discussed only as to their technical potential. Detailed studies including marketing and financial analysis of model enterprises are required to estimate the economic viability of the technologies.

2.1.1 Penaeus monodon

Tiger shrimp farming is the only commercial technology developed in Sri Lanka's coastal zone. Development has been concentrated in the area from just south of Chilaw Lake to the mouth of Puttalam Lagoon. There was not control over the development of the industry which is now suffering the consequences of environmental overload.

The extensive lagoon systems and low relief coastal plain of the eastern sea shore will allow the shrimp farming industry to expand considerably. Innovative systems can be developed for open coastal sites. Sea water wells supplying water to closed systems may lead to the expansion of the industry in a much more sustainable manner.

2.1.2 Penaeus indicus

The white shrimp, P. indicus, is not widely cultured but is well suited to high salinity environments beyond the optimum range for P. monodon. Salinity beyond 35 ppt is inimical to good growth of tiger shrimp, whereas P. indicus thrives up to 50 ppt. The average size after 150 to 180 days of culture is 20 g. The lower size is compensated for by much higher stocking densities with increased aeration which result in yields of 5 to 7 tons/crop. The white shrimp has the advantage of readily maturing and spawning in captivity. Larval survival in the hatchery is higher than P. monodon. Although higher stocking rates of 30 to 60 PL's/m2 are used, good hatchery survival and lower cost of brood stock should result in lower PL prices.

A management strategy could include tiger shrimp production during low salinity and white shrimp during high salinity. Intensive white shrimp culture might be possible in lined ponds constructed on sand on open sea coasts where moderate surf prevails. However, the economic feasibility of white shrimp production needs to be demonstrated in Sri Lanka.

2.1.3 Scylla spp.

Two species of mud crab are found in Sri Lankan waters, S. serrata and S. oceanica. S. serrata is smaller than S. oceanica and is sold locally. Crab fattening operations usually use S. oceanica . Mud crab "fattening" is increasingly popular in the shallow lagoons and bays around the country. Recently molted "water crabs" are held for 2 to 3 weeks and fed fish offal. The fattened crabs are exported through Colombo to SE Asian markets. Both sexes are used in fattening operations, so there is the danger of damaging the fishery if the capture of female crabs continues.

Mud crab culture has not yet developed in Sri Lanka, but is well suited to small scale operations and can be done in a way that minimizes environmental impact. Expansion of mud crab production confronts two major constraints: lack of hatchery produced seed and reliance on low value fish as feed. Commercial hatchery production has not been achieved anywhere, although the life cycle has been closed in captivity. Cannibalism at the megalopa stage seems to be the bottleneck in hatchery production.

The current reliance on juvenile wild crabs for seed stock is not sustainable and threatens the viability of the fishery. Hatchery research is underway in Australia, Malaysia and Taiwan. Successful technology developed in these countries could be transferred to Sri Lanka. Ceylon Grain Elevators has had promising results with artificial feeds for grow out which might lead to less dependence on low value fish.

2.1.4 Artemia

Brine shrimp are widely used in the ornamental fish industry both in Sri Lanka and abroad and are vital to the shrimp and prawn hatchery business. Extensive field trials by NARA have demonstrated the feasibility of both biomass and cyst production in Sri Lankan salterns. Some commercialization has developed to supply local markets in the ornamental fish and hatchery sectors. The Great Salt Lake of Utah, USA continues to be the major supplier of brine shrimp cysts to the aquaculture industry, but this source is* in jeopardy due to over exploitation. Although the production potential of existing salterns appears too small to enter the international market, cyst production can be increased to insure the Sri Lankan aquaculture industry has a sufficient supply of this basic input.

2.1.5 Crassostrea spp.

Field trials by NARA have demonstrated the technical feasibility of culturing oysters. The most promising sites are to be found in the extensive lagoons and embayments of the east and northeast coasts of the country. Abundant spat are reported from Trincomalee Bay. Weak local market demand is the most important constraint confronting development of oyster farming in Sri Lanka. Tourism offers opportunities, provided the product can be certified as sanitary. Export to Singapore and Malaysia would also be possible if the oysters are depurated.

Farming systems for oysters are very diverse. Farmers adapt the system to their local environment. Intertidal culture is done on racks, rocks, cement poles and stakes. Long lines, racks and rafts are employed in deeper water. The spat source and market influence the culture method as well as the environment. The most common method in Thailand is intertidal cement poles to which spat are cemented. Intertidal racks and stakes are popular in Thailand, while in Malaysia long lines, rafts and racks are used for subtidal farming. In the western tropical Pacific, the majority of commercially cultured tropical oysters belong to the genus Crassostrea and include C. belcheri, C. irredalei and C. arakensis. There is more limited production of Saccostrea echinata and S. cucullata. Commercial culture has not yet developed in south Asia although NARA scientists have developed appropriate methods for farming C. madrasensis in Sri Lanka.

Oysters show promise as a component of biological treatment of shrimp pond effluent water. Provided sufficient spat are available, shrimp farms could become a major source of farmed oysters.

All species of the genus Crassostrea have similar characteristics. They tolerate moderate to high turbidity, are euryhaline but do best in a range of salinity from 15 to 25 ppt. Crassostrea are also fast growing, reaching market size in 6 to 9 months. Species are difficult to differentiate from external shell characteristics and the taxonomy of Indo Pacific species is not very clear.

2.1.6 Perna spp.

Mussels are another species which has been experimentally cultured in Sri Lanka but not yet commercialized. The market potential is not known, but probably has poor export prospects. It is reported that dried mussel meats from Trincomalee can be found in some fish markets. Mussels can be incorporated in biological treatment systems for shrimp farms, but are less tolerant of salinity fluctuations. They have been grown in Galle and Puttalam Lagoon, but are best suited to the lagoons and bays of the east and northeast coast.

Perna is grown subtidally on ropes suspended from rafts or on long poles pushed into the sea bed. Spat are sometimes collected from mussel beds on subtidal rocks or they may set directly on poles. Growth is rapid and thinning may be required. Marketable mussels are obtained in 6 to 8 months under normal growing conditions. Like oysters, mussels are well suited to small scale production and their culture is compatible with the mangrove environment.

2.1.7 Gracilaria spp.

Red algae of the genus Gracilaria are found associated with seagrass beds in the lagoons and bays around the coast of the country. Experimental work by NARA has been incomplete, but indicated there may be potential for its culture. The main product extracted from the seaweed is a phycocolloid known as agar. Agar has both a domestic and export market depending on its quality. A pilot project has been completed in Puttalam lagoon with support from the Canadian International Development Agency (CIDA). Gracilaria was propagated vegetatively and harvested by selective pruning. The results indicated that commercial development by poor fisherfolk might be viable.

Gracilaria can be grown in open water or ponds. Open water culture is suitable for small scale production. It can be incorporated into treatment systems for shrimp farm effluents. Grazing by juvenile rabbit fish is the most serious constraint facing open water culture, while pond construction costs influence the economic viability of pond production unless it is part of a biofiltering system for closed system shrimp culture. Open water culture is done adjacent to natural stocks, usually in sea grass beds. The depth of culture is approximately 0.6m. Propagules are taken from the natural stocks. Spore setting has succeeded experimentally, but needs to be tried on a larger scale. The ideal salinity range for G. edulis in Sri Lankan waters seems to be from 18 to 35 ppt.

There are 2 open water systems currently in use for commercial Gracilaria culture. These are the stake and line method and the floating method. The stake and line method has been tested in Puttalam Lagoon and appears to be successful. The lines are set at a depth of 0.6 m below MLLWS.

The floating method enables seaweed culture in deep water, although the location should be sheltered. Any inexpensive floatation can be used. A bamboo frame supporting a grid of lines is used in the West Indies with success. Simple longlines can be made with plastic jerry cans, fish net floats or other locally available materials. Longlines are suitable for more exposed locations. The seed line should be set about 0.5 m below the surface. Floating methods are one way to avoid grazing fish, which usually inhabit reefs or shallow sea grass beds. It is not unusual to have to test many sites until a suitable location is found.

2.1.8 Holutherioidea

Sea cucumbers, also known as trepang or beche de mer, are highly prized in east Asian markets. Many stocks in the Indo-Pacific region have been over exploited to satisfy the growing demand from China, Taiwan and the SE Asian countries where ethnic Chinese live. The rising prices and increasing scarcity have prompted attempts to culture these animals. Some success has been achieved in China and experiments have had positive results in India. NARA scientists are currently investigating culture techniques, but probably a decade will be required to develop commercially viable culture technology. .

The value of trepang depends very much on the species, since quality is species dependent. Culture would have to be developed for Holutheria scabra, H. scabra var. versicolor, H. nobilis and H. fuscogilva, the most valuable species. Their habitat requirements under culture conditions are not well known, but these species are found on muddy and muddy sand sea floors. They may be encountered in sea grass beds and occasionally in waters subject to river influence. H. scabra is an inner reef flat species, H. nobilis and H. fuscogilva frequent reef passes and slopes, while H. scabra var. versicolor is found in lagoons (Conand 1990). Sri Lanka exports 60 tons per year, of which 20% are from Puttalam. This represents 0.01% of the world market of 600,000 tons. Dried trepang currently sells for 3000 to 6000 SLR/kg, with about 20 pcs per kg.

Experimental culture of H. scabra and H. atra will be undertaken at the NARA Kalapitiya Field Station. Fisherfolk could do the farming from the juvenile stage using cages or pens. Sea cucumbers are stenohaline requiring about 32 ppt. The larval rearing temperature is 30.2 °C.

2.1.9 Hybrid Tilapia

Hybrids of Oreochromis spp. have been developed for brackishwater culture. Some breed in seawater, while others reproduce in freshwater. The fry of freshwater breeding varieties can acclimatize to brackishwater and may be sex reversed to provide all male fingerlings for stocking in pens or cages. Hybrids exhibit rapid growth and have high feed conversion ratios. They adapt readily to artificial pelleted feeds. Small scale culture in pens and cages has proved profitable in Malaysia, Thailand, and Indonesia to name a few countries of the many where hybrid culture has been successful. They could also be cultured in abandoned shrimp farms.

Brackish ground water is common along the coast of Sri Lanka and could be used to culture hybrid tilapia in small ponds. While these fish can tolerate a wide salinity range, there should not be abrupt changes. High salinity tolerant hybrids like the Florida red tilapia are suitable for cage culture in sea water.

2.1.10 Marine fin fish

Commercial culture of tropical marine finfish is limited to sea bass (Lates calcarifer), sea bream (fishes of the family Sparidae), groupers (Epinephulus spp.), milkfish (Chanos chanos), mullet (Mugil cephalus) and snappers ((Lates calcarifer)).

Sea breams belonging the Sparidae are commercially cultured in the Mediterranean Sea and the Persian Gulf. Japan has had a substantial production of sea breams for several decades. Promising species in Sri Lanka are Rhabdosargus sarba and Mylio latus.

Marine fin fish may be reared in land based or cage systems. Only a very high market price can justify land based systems. The high cost of hatchery production is a further impediment to the development of marine fin fish culture in Sri Lanka, at least in the initial phase of development. A publicly supported hatchery and demonstration farm could provide the necessary impetus to start an industry.

The milkfish, Chanos chanos, has been the object of experimental culture in Sri Lanka in the past, but there was no commercialization. Milkfish are cultured in tide fed ponds in the Philippines and Indonesia. A tidal range of at least 1.5 meters is required for adequate water supply, whereas the maximum tidal range in Sri Lanka is about 70 cms. A serious environmental constraint facing inter tidal pond development is its interference with the mangrove ecosystem.

It might be interesting to look at the viability of milkfish culture in abandoned shrimp ponds or pens. Supplementary feeding could possibly allow sufficient production to cover pumping costs in ponds. In any event, much less water exchange would be required compared to shrimp farming. Milkfish may also be cultured in pens with supplementary feeding using low cost inputs such as rice bran and oil cake. Resolving user conflicts would be an important component of developing pen culture of milkfish. Community-based or cooperative culture might be one approach. Women's groups could become involved in pen culture. The capital investment for pen culture is relatively low, but there is a high risk of social conflict.

Hatchery production of fingerlings can also serve as the basis for developing culture based fisheries in lagoons and other semi-enclosed water bodies. In light of declining coastal fisheries and over exploited lagoon resources, there is increasing interest in this approach to enhancing fish production. Culture based fisheries combine aquaculture technology and community management of local fisheries resources.

2.2 Matrix criteria

Criteria which impact or control aquaculture systems development were identified and ranked. Ranking was done on a 4 point scale which will be represented on overlays by a monochrome shading scale. The ranking scale will be as follows:

0 Not suitable for development
1 Moderately suitable, affects the culture system negatively
2 Neutral, or favors the development of the culture system
3 Positive, successful development highly likely

Each criterion is, in turn, further refined by sub division into parameters. Parameters are ranked using the same scale as applied to criteria. The score for a criterion is the product of the criterion rank by the parameter rank. In situations were data is insufficient to rank parameters, an approximation of the score for a criterion may be used. In this case, the score is more intuitive than objective as it would be based on general experience. A sample matrix is shown in Table 2.

2.3 Ranking parameters

2.3.1 Elevation
2.3.2 Soil pH
2.3.3 Soil texture
2.3.4 Vegetation, land use and user conflicts
2.3.5 Access to infrastructure
2.3.6 Salinity
2.3.7 Water quality criteria

Physical, chemical and social parameters impact aquaculture development but obviously not all parameters are applicable to every system considered in our GIS data base. Ranking scores for parameters are shown in Table 2.

Table 2. Matrix for ranking coastal aquaculture zones

2.3.1 Elevation

Elevation (or depth) in reference to mean sea level is a unique criterion because it is germane to all coastal aquaculture systems. Shrimp culture in the supratidal zone is now the preferred technology, but pumping costs and sea water intrusion into freshwater aquifers limit pond construction to elevations less than 5 m. The tidal range along most of the coast of Sri Lanka is less than 1 m, practically eliminating the possibility of intertidal pond construction. Furthermore, pond construction in the intertidal zone conflicts with mangrove and salt marsh conservation.

Submerged culture systems employing rafts or cages require sufficient clearance between the culture system and the sea floor. Fin fish cages should be sited in at least 5 m depth to allow adequate cage depth and water circulation.

Sea cucumbers are cultured in shallow water less than 5 m depth. Seaweed may be grown in less than 1 m but below MLLWS tides. Oysters can be cultured in the intertidal zone or completely submerged. The elevation depends on the degree of fouling which is usually higher in higher salinity water.

2.3.2 Soil pH

Acidic soils are common in the coastal zone, originating from anaerobic decomposition of organic matter. The end product is iron pyrite, which when oxidized by exposure to air, yields sulfuric acid. Very low pH soils may produce toxicity through the release of aluminum ions. Primary production is also very poor because phosphate is precipitated as insoluble calcium phosphate.

The ideal pH range for shrimp farming is 6.5 to 7.5. Soils above pH 5 may be used, but more acid conditions cause problems. Reclamation of acid sulphate soils is possible, but may be costly if the pyrite load is high. Potential acid sulfate soil is one reason for avoiding mangrove forests, which usually have high potential sulfate acidity.

Soil pH is somewhat related to soil texture, but one often encounters pyritic loam and sandy loam slightly above the elevation of mangroves, such as along the western shore of Chilaw Lake.

Soil pH is of little relevance to aquaculture systems which do not involve pond construction or other excavations. Sea water is a highly buffered medium, consequently pH of the aquatic medium is seldom a limiting factor. In extreme cases of acidic runoff from disturbed mangrove forests or land clearing, excessive acidity could cause an acute problem.

2.3.3 Soil texture

The feasibility of pond culture is directly related to soil texture, but has little relevance to other technologies such as raft and cage culture. Mangroves develop on alluvial soils in which clay predominates. As elevation increases, pyrite content declines while pH normally rises. At the same time, particle size tends to increase unless alluvial soils dominate, in which case clay would be the most common soil type. Clay to sandy loam soils are suitable for pond construction. Ponds constructed in sandy loam soils experience seepage water loss, but the loss may amount to only a few cms a week.

Pond liners can be used in sandy soils if high value crops like shrimp are to be cultured. There are examples of lined ponds in Saudi Arabia and Mexico. Pond liners have also been used in very acidic soils to isolate the culture system from the negative effects of high acidity.

2.3.4 Vegetation, land use and user conflicts

Vegetation reflects soil texture, pH and influences pond development costs. The importance of the mangrove ecosystem to coastal fisheries and biodiversity precludes its occupation and destruction for pond culture. On the other hand, mangroves are ideal sites for non-intrusive forms of aquaculture such as bivalve molluscs, mud crab and cage culture. Similarly, the sanctity of wild life preserves must be respected.

Saline ground water underlies significant portions of the coastal zone. Coconut plantations, halophytic vegetation, salt pans and single crop padi lands can be found over saline ground water. These areas are ideal for pond development, particularly shrimp farms. Construction costs and environmental impacts are low. Shrimp culture usually is the most profitable use of these lands. Because of saline ground water and soils, irrigated agriculture is impossible.

Other than pond culture, vegetation is of minor importance. Holuthurians require sediments suited to their normal habitat, but this varies with the species. The most valuable species prefer muddy sand. Open water Gracilaria farming has more chance of success if done in its natural habitat. In Puttalam Lagoon, for example, it is found in association with sea grass which inhabits sand to sandy mud substrates.

User conflicts are serious impediments to aquaculture development and have led to conflicts in almost every country in which the industry has developed. The western coastal zone is heavily populated. Resources are already under pressure and in many cases over exploited. Mechanisms for resolving conflicts should be encouraged if aquaculture is to develop as a sustainable industry.

2.3.5 Access to infrastructure

Open water culture, among which are rack and raft culture, need little infrastructure. Even remote areas accessible only by boat are quite suitable for these systems. Shrimp farming is the prime example of a technology requiring substantial infrastructure support in the form of all season roads and 3 phase electricity in sufficient quantity.'

2.3.6 Salinity

Marine organisms can be broadly characterized as euryhaline or stenohaline. Shrimp and oysters belong to the former, while many marine finfish species are in the latter group. Even euryhaline organisms thrive only within a range, albeit wide, of salinity. Thus salinity is an environmental parameter controlling the selection of species and technologies. Very few brackishwater species grow well at either extreme (0 to 10 ppt and above 35 ppt), although they may be able to tolerate them for short periods of time.

The parameters selected in the salinity category reflect the optimum ranges for the various matrix species. There is overlap in many instances, particularly in the mid range of 15 to 25 ppt.

2.3.7 Water quality criteria

Water quality indicators include dissolved nitrogen, hydrogen sulfide and biological oxygen demand (BOD). Dissolved nitrogen is partitioned into ammonia nitrogen, nitrite and nitrate. The most critical parameter is dissolved ammonia due to its toxicity if tolerance limits are exceeded.

Optimum ranges and limits for some of these parameters are known for shrimp, but little data exists for other species. Data collected during the survey will be useful as a baseline against which to measure the impact of future aquaculture development.

3. Zoning for coastal aquaculture

3.1 Preparation of base maps and overlays
3.2 Field surveys
3.3 GIS data base revision
3.4 Publication and dissemination
3.5 Incorporation into CZM regulations

The zoning process consists of 5 steps:

1) preparation of base maps and overlays,
2) field surveys,
3) GIS data base revision,
4) preparation and publication of zoning for each species,
5) incorporation into coastal zone management (CZM) regulations.

3.1 Preparation of base maps and overlays

There appears to be a substantial amount of data relevant to coastal aquaculture zoning, but it is dispersed among several ministries and departments. Maps, reports, studies and surveys from both the published and unpublished literature can be availed of to build a GIS data base. The first task is to find, collect and collate these materials in the Planning and Information Unit.

Digitized maps of the coastline of the country including lagoons, bays and harbors will serve as base maps on which specialized overlays will be superimposed to identify areas suitable for various culture species. These 1:50,000 scale maps currently not available in the PIU are listed in Annex 8.1 and are available from the Survey Department. A valuable source of maps and aerial photographs is Bandara, CM. Madduma. 1989. A survey of the coastal zone of Sri Lanka. Coast Conservation Department.

Large areas of coastline may fall within certain isopleths of some parameters, for example, elevation. An exclusionary screening process has to be applied to reduce potential zones to a reasonable area. Very general criteria may be considered at this stage. Some obvious exclusionary criteria or parameters are urban areas, harbors, sea cliffs, swamps, navigation channels, irrigated padi, and heavily exploited lagoons.

After excluding obviously unsuited areas, the next step is to construct a series of digitized overlays of criteria relevant to each species or species group. The construction of the overlay will depend on the particular criteria. The vegetation overlay for P. monodon or P. indicus, for example, would consist of plots of the various vegetation parameters found within the zone. At this stage, plots are developed from data shown on 1:50,000 scale maps or from specialized maps of soils, ground water or particular types of vegetation. The overlay of some parameters like salinity will be a plot of isohalines.

After the overlays of criteria have been completed, the parameters can be ranked by the color coding scheme. The suitability of areas within a zone would be indicated by combinations of the primary colors or if unsuitable, blacked out.

3.2 Field surveys

The field survey has several roles: fill lacunae identified in the construction of the GIS data base, ground truth remote sensing data, and establish base line data. Field surveys are time consuming and expensive and should be limited to these functions. A sample survey form is shown in Annex 2.

The survey plan is developed prior to the field survey. Information needs are identified during the preparation of base maps and overlays as described in section 3.1. Sampling is based on transects perpendicular to the shoreline. Preliminary transects and station locations are identified on the base map according to the information to be acquired in the field. The coordinates of the sampling station are listed for GPS referencing in the field. If GPS is not available, triangulation must be used. The samples or measurements which have to be taken will be determined by the lack of corresponding data in the GIS data base. For example, contour intervals on 1:50,000 scale maps are 100 m, which is far too coarse for our purposes. Therefore, in zoning for shrimp culture, we will have to identify points along the transects where elevation will be measured with a transit or theodolite in reference to mean sea level at intervals of 0.5 m up 5 m or a distance of 2 km from the shoreline, whichever comes first. The precise positioning of the transect or sampling points along it may have to be adjusted in the field.

If soil data is required, sampling points can be tentatively identified on the basis of vegetation cover, each point representing a vegetation type since vegetation is a good indication of both soil texture and elevation. Bathymetry, salinity and undersea vegetation will require the use of small boats and water sampling apparatus such as Van Dorn bottles. Sampling can also be done while swimming with snorkeling gear. The terminus of the transect is marked with a stake or buoy referenced to 2 stakes set on the land side of the transect line. GPS positioning would greatly facilitate sampling point identification. Marine transects can be marked with a light line or raffia and sampling points marked and measured along the line. Defining salinity ranges may require repeated observations at the same sampling points over a long period of time. Dry and wet season peaks may be measured, but at least one year and two samplings would be required.

Acquiring base line data will enable development to be monitored and controlled. It is particularly important to establish water quality baseline data in zones that have not yet been developed for aquaculture. The base line data will tie the zoning process to regulatory measures through the granting of permits and monitoring of project performance. When water quality or other environmental standards begin to show signs of deterioration, development can be stopped permanently or until remedial measures are taken.

During the course of this mission, three brief field surveys were conducted. The objectives were to assess the state of aquaculture development in the northwestern, western and southern provinces and to indicate where detailed field surveys might be made.

3.3 GIS data base revision

Data acquired in the field will be incorporated into the corresponding overlay in the GIS data base. Data collected in on-going surveys in the context of other projects can be used to continuously update the GIS database.

Land use changes, sometimes rapidly, and is an example of the kind of data which needs constant updating. Aquaculture itself may be a significant contributor. Shrimp farm development may occur very rapidly and should be carefully tracked by the PIU. Other forms of coastal aquaculture are likely to develop rather slowly in Sri Lanka, but nevertheless need to be monitored and included in the GIS database, should development proceed.

3.4 Publication and dissemination

The outputs of the zoning process are the publication and dissemination of results to the interested public and the incorporation of coastal aquaculture zoning into CZM regulations. A special publication could be produced explaining the methodology used to establish coastal aquaculture zones with presentation of maps indicating appropriate zones for different species. The publication could serve as a guide for investors as well as policy makers.

3.5 Incorporation into CZM regulations

Zoning will only be effective if it is incorporated into enforceable CZM regulations. When the eastern and northern coasts become accessible for development, there may well be a "shrimp gold rush" to the area. It will be imperative to control development to avoid the situation which occurred in over development of the industry, exemplified in the Chilaw - Puttalam area.

4. Zoning for species and technologies

4.1 Penaeus spp.
4.2 Scylla spp.
4.3 Artemia
4.4 Crassostrea spp.
4.5 Perna spp.
4.6 Gracilaria spp.
4.7 Holutherioidea
4.8 Hybrid tilapia
4.9 Marine and brackishwater fin fish

General zoning for aquaculture is not feasible since each culture system or species has its peculiar requirements. Some criteria are common to several species, which we have referred to as a species group. Zoning parameters are, in general, discussed for grow-out systems. Hatchery siting is discussed briefly in section 5.

4.1 Penaeus spp.

Both P. monodon and P. indicus share most criteria necessary for successful culture. P. indicus may be better adapted to salinity above 45 ppt. Shrimp farming in Sri Lanka is restricted to the supratidal zone as a consequence of the very narrow tidal range of less than 1 m. After excluding areas obviously unsuited to aquaculture, one can identify potential shrimp culture zones based on siting for some of the existing shrimp farms, as well as general site selection criteria and applying corresponding criteria to maps. Several local farms such as Indiwary and Link Aqua Farms have used innovative technology to expand the area suitable for shrimp farming.

The first step is to digitize the 1:50,000 map which includes the potential shrimp culture zone. Features of this base map will include the shoreline, including all water bodies (lagoons, channels, rivers, etc.). Other information on the 1:50,000 map can also be included in the base map. Vegetation, settlements, roads and highways, and land usage such as padi land and salterns are examples of information which can be digitized from the survey maps. The contour interval is 100 m which is far too low a resolution for siting shrimp farms, but it can be useful to include. The inland boundary of the zone map should be about 2 km from the shoreline, but this should not be rigid if suitable elevation, soil and ground water conditions are found further inland or the 5 m contour is reached in less distance.

When the base map is completed, overlays can be prepared for elevation, soils, aquifers, mangroves, salinity of adjacent water bodies, depth contours up to 5 meters and water quality parameters.

4.2 Scylla spp.

Two species of mud crab are found in Sri Lanka, of which only S. oceanica is being used for "fattening." There is no culture of either species at the moment. However, the criteria for culture and fattening should be similar for both species. Mud crabs are one of the species well suited for culture in the intertidal zone in or adjacent to mangroves or in other shallow, protected waters.

The first overlay on our base map would be the distribution of mangroves. The bathymetric overlay would contain the MLLWS isobath. The mud crab culture zone is that area encompassed by the intertidal zone within lagoons and bays.

The crab fattening zone coincides with the culture zone but also extends to elevations above MHHW. This is because shore based installations are possible. They may use tanks above ground level or shallow excavated lined pools. In heavily utilized lagoons such as Negombo, this may be the only practical way to do fattening or even culture. The higher limit of this zone would be the 1 m contour interval. Culture and fattening are possible anywhere along the lagoon shoreline. They can be so-called "backyard" operations which can be carried out even in lightly urbanized areas. Open sea coasts are not suitable, however.

Mud crab culture and fattening depend on a reliable source of fish offal and low value by catch. Proximity to fishing ports would be a definite advantage to the culturist, so the infrastructure overlay could show fishing ports, feeder roads and highways.

4.3 Artemia

Anemia or "brine shrimp" occupies a unique niche in which it has few predators other than birds. Because it inhabits only extremely saline water, its distribution and culture is restricted to salterns, mainly the two large commercial operations in Puttalam and Hambantota, respectively.

The first overlay on the base map will plot existing salterns, both small and large scale. These mark the zones where brine shrimp can be cultured with some modification to the existing salterns, particularly if they are small scale operations. The second overlay should encompass the one meter contour adjacent to lagoons. The third overlay would be for soil. The brine shrimp zone is identified where soils of low permeability coincide with the area between the MHWS and the 1 m contour.

4.4 Crassostrea spp.

The first step in zoning for oyster culture is to select lagoons and bays where successful trials have been conducted and those sheltered water bodies which might be suitable. Zones for oyster culture should include depths from MLLWS to 5 meters in sheltered waters such as lagoons and bays. These isobaths can be plotted on the first overlay. The second overlay should show isohalines for the lagoon or bay selected for zoning. Another overlay can indicate mangroves, which are compatible with oyster farming when done around the fringes of the forest and in channels coursing through the trees. Oyster culture in Sri Lanka is likely to depend on natural spatfall, so the locations of oyster stocks should be mapped to the extent they are known.

4.5 Perna spp.

Depth and salinity are controlling criteria and can be plotted overlays. The overlay prepared for oysters may be suitable with minor modifications, as well as the overlay of isohalines. Mussels can be cultured from about 2 m to 5 m depths or more, depending on the culture method. Poles are used in shallow water and rafts or long lines in deeper water. Natural mussel beds can be plotted on overlays similar to those plotted for oyster stocks. The locations of natural mussel beds will be likely sites for mussel culture using either poles or suspension methods.

4.6 Gracilaria spp.

It is likely that Gracilaria will be produced from open water culture and as a by product of biofiltration and treatment in shrimp farms. Seaweed culture zones coincide with seagrass beds, which are the natural habitat of Gracilaria edulis. Therefore the first overlay for the seaweed culture zone will be a plot of the distribution of seagrass beds. The isohalines for 18 ppt and 35 ppt can be superimposed as the second overlay. Salinity within this range should occur at least 6 months of the year. Lines are set at 0.6 m depth when the stake and line system is used so the water depth must be at least 1 m below MLLWS tide.

The floating method allows seaweed culture in deep water so the most important criteria are salinity and exposure. Deep lagoons and bays are ideal and can be zoned for this technology provided salinity falls within the required range at least 6 months of the year. The area between the 2 m and 5 m isobaths can be used to define the depth overlay, although floating seaweed culture could be done in deeper water.

4.7 Holutherioidea

Sea cucumber culture is at the experimental stage in Sri Lanka so the parameters used to define potential zones are not well known at this point. However, we can use the known requirements for species which are harvested from wild stocks. For zoning, sediment data and salinity isopleths and depth of-1 to -5 m can be combined.

Isohalines enclosing water with a year round salinity of 32 ppt will be the first overlay. Isobaths of the -1 and -5 meter depth contours can be the second overlay, while sediment maps indicating the extent of muddy sand bottom are overlaid to indicate the area suitable for trepang culture.

4.8 Hybrid tilapia

Three culture systems can be zoned for: pen, cage and pond. Pen culture requires shallow water of 2 to 3 m below MLLWS, sandy to muddy sea floor.

Brackish ground water is a resource which could be used to culture hybrid tilapia in the coastal zone in ponds. The criteria to be plotted are ground water salinity, soil texture and land use. Where brackish ground water underlies seasonal rain fed rice fields, hybrid tilapia culture could be a profitable alternative. For these sites, it is critical to identify discharge points for pond effluent. Alternatives are to inject back into the aquifer after treatment or discharge into an existing brackishwater lagoon, again after treatment. Ground water salinity data is available from NARA studies and possibly from the Water Resources Board. Soil texture suitable for pond construction ranges from sandy loam to clay. The zone map for tilapia pond culture will , consequently have the following overlays: ground water salinity, soil texture and land use. The topography should also be taken into account to identify discharge routes for pond effluent.

4.9 Marine and brackishwater fin fish

Marine finfish species usually require oceanic quality water for their hatchery and grow-out phases. Brackish water finfish include sea bass (Lates calcarifer), mullet (Mugil cephalus) sea bream and milkfish (Chanos chanos). These fish require oceanic water for hatchery fry production, but grow well in brackish water. Sea bream and rabbit fish are better adapted to the marine environment and have both local markets and export potential to the Arabian Peninsula.

Because marine finfish require the highest water quality, culture systems must be located in deep bays which have high exchange rates with the open sea. The most common technology is cage culture. Cages are 2 to 5 m deep and require at least 2 m clearance between the bottom of the cage and the sea floor at MLLWS. Cages also require sheltered locations protected from open sea swell and storm waves. Shallower areas of lagoons and bays can be zoned for pen culture. At least one meter below MLLWS is required for milkfish, but should be deeper for sea bass.

Sites for cage culture appear somewhat limited. Trincomalee Bay may have the necessary conditions, but other coastal lagoons are subject to wide variations in water quality, including salinity. Recent advances in cage design have led to the development of units which can be operated on the high seas. It might be feasible to rear sea bream and sea bass in such systems, although they are costly. Shore based systems are technically feasible, but are probably not financially viable because of high construction and pumping costs.

5. Zoning for hatcheries

Much of the Sri Lankan coast is suitable for marine hatcheries. The most important requirements are access to oceanic seawater and adequate distance from river mouths to avoid any freshwater influence. Sand beaches are preferable for the ease of constructing a seawater intake. The hatchery site must be within easy reach of 3 phase electricity and all-weather roads. Excellent sites can be found along the Northwest Province on the sea coast and the dry zone of the south coast from Tangalle east to the boundary of Bundala and Yala Wildlife Sanctuaries. This coast fronts the open Indian Ocean and there is very little fresh water influence. The reefs along the south coast are in relatively good condition and could serve as a source of brood stock.

Fry and fingerlings produced in the marine finfish hatchery can be marketed to cage and pen farmers and can be supplied to fishers to establish culture based fisheries.

6. Culture based fisheries

All the coastal lagoons of Sri Lanka are heavily exploited by surrounding villagers. The growing pressure on inshore fishery resources imperils their recovery. Culture based fisheries can be undertaken to meet the growing demand for fresh fish and at the same time improve the income of fisherfolk who depend on the inshore fishery.

Culture based fisheries blend aquaculture technology and capture fisheries. Hatcheries produce fry and fingerlings which are stocked in lagoons and sheltered bays. Species are selected which will tend to remain in the target water body or migrate into it some time after release. Fish low on the food chain are preferable to top carnivores although market factors must also be taken into account in species selection. Suitable species might include sea bream and mullet, both of which can be bred in hatcheries.

The problems confronting aquaculture development on the south coast have been mentioned. The introduction of culture based fisheries is an ecologically sound way to increase fish production and at the same time involve local communities in a culture based fishery. Some initial work is underway in Rekawa Lagoon with tiger shrimp and could readily be expanded to include sea bream, rabbit fish and mullet. Other lagoons around the coast could also benefit from the development of culture based fisheries.

7. List of references

Al-Thobaiti, S.; C.M. James. 1996. Shrimp farming in the hypersaline waters of Saudi Arabia. Infofish International 6/9 (26-31).

Anonymous. 1981. Coast conservation act. No. 57 of 1981.

Anonymous. 1994. Wetland Site Report. Puttalam Lagoon, Dutch Bay and Portugal Bay. Wetland Conservation Project. Central Environmental Authority/Euroconsult.

Anonymous. 1994. Wetland Site Report and Conservation Management Plan. Mundel Lake & Puttalam Corridor Channel. Wetland Conservation Project. Central Environmental Authority/Euroconsult

Anonymous. 1985. Coastal environment management plan for the west coast of Sri Lanka: preliminary survey and interim action plan. Econ. Soc. Comm. Asia and the Pacific. United Nations.

Arulananthan, K.; L. Rydberg; U. Cederlof; E.M.S. Wiyeratne. 1995. Water exchange in a hypersaline tropical estuary, the Puttalam Lagoon, Sri Lanka. Ambio V 25 No. 7-8 (438-443).

Bandara, C.M. Madduma. 1989. A survey of the coastal zone of Sri Lanka. Coast Conservation Dept.

Bandara, C. M. Madduma; I.M. Ismail; R. Wijeratne; D. Jayawickrama; C. Wijenaike; R.S. Jayaratne. 1986. Second Interim Report of the Land Commission. Strategies for conservation and development of coastal lands. Land Commission, Colombo, Sri Lanka.

Coastal Conservation Department. 1990. Coastal zone management plan. Sri Lanka Coast Conservation Dept. Colombo, Sri Lanka.

Conand. C. 1990. The fishery resources of the Pacific island countries. Part 2. Holothurians. FAO. Fisheries Tech. Paper 272.2 142 pp.

Corea A.S.L.E.; J.M.P.K. Jauasinghe; S.U.K. Ekaratne; R. Johnstone. 1995. Environmental impact of prawn farming on Dutch Canal: the main water source for the prawn culture industry in Sri Lanka. Ambio V 25 No. 7-8 (423-427)

Coutts, R.R.; C.A. McPadden. 1994. The use of remote sensing and GIS techniques to survey and map the Malacca Straits coastal environment and shrimp aquaculture in North Sumatra Province. In Geographical Information Systems for natural resource management in South East Asia. S.T.D. Turner and R. White, eds.

Dayaratne, P.; A.B.A.K. Gunaratne; M.M. Alwis. 1995. Fish resources and fisheries in a tropical lagoon system in Sri Lanka. Ambio V 24 N 7-8 (402 - 410)

Dayaratne, P.; 0. Linden; M.W.R.N. De Silva. 1995. Puttalam Lagoon and Mundel Lake, Sri Lanka: A study of coastal resources, their utilization, environmental issues and management options. Ambio V 25 No. 7-8 (391-401)

Dayaratne, P.; O. Linden; M.W.R.N. De Silva. 1997. The Puttalam/Mundel estuarine system and associated coastal waters. NARA. Colombo Sri Lanka. 98 pp.

Funge-Smith, S. 1997. Disease prevention and health management in coastal shrimp culture. Sri Lanka. Field Document 1 TCP/SRL/6614, FAO Bangkok.

Ganewatte, P.;LA.D.B. Smaranayake; J.I. Samarakoon; A.T. White; K. Haywood. 1995. The coastal environmental profile of Rekawa Lagoon, Sri Lanka. Coast Conservation Dept. NARA, Coastal Resources Management Project.

Jacobs, P. Garner, J and Munro, D.A. 1987. Sustainable and equitable development. In: Conservation with Equity (ed. P. Jacobs and D.A. Munro), Proceedings Conference on Conserv. and Develop. - Implementing World Conservation Strategy. Ottawa 31 May-5 June 1986. International Union for the Conservation of Nature, Cambridge, U.K.

Jayakody. S. 1997. MS. Shrimp fishery and related biological process Rekawa Lagoon, Tangalla. Working Paper No. 1/1997. NARA/Coastal Resources Management Project University of Rhode Island.

Jayasinghe, J.M.P.K. 1995. Regional study and workshop on aquaculture sustainability and the environment. Sri Lanka Study Report. ADB RETA 5534 NACA,

Jayasinghe, J.M.P.K. 1997. Treatment systems for shrimp culture. NARA. Colombo.

Jayasinghe, J.M.P.K. 1997. Investigations on the disease out-breaks in shrimp culture systems developed on problem soils. NARA Research Grant ARP/12/153/163. National Aquatic Resources Research and Development Agency Colombo 15 Sri Lanka.

Johnson, P.; R. Johnstone. 1995. Productivity and nutrient dynamics of tropical sea-grass communities in Puttalam Lagoon, Sri Lanka. Ambio V. 24 N 7-8 (411-417).

MOFARD. 1990. National Fisheries Development Plan

Muir, J. F. 1996. A systems approach to aquaculture and environmental management. In: Aquaculture and -water resource management. D. J. Baird, M. C. M. Beveridge, L.A. Kelly and J. F. Muir, eds.

NARA. MS. Survey to identify suitable areas in the coastal belt of Sri Lanka for prawn culture. Phase I.

NARA. MS. 1995. Report on the preparation of a zonal plan and identification of land for further development for shrimp farming in Northwestern coast.

Olsen, S. D. Sadacharan, J.I. Samarakoon, A.T. White, H.J.M. Wickremeratne, M.S. Wijeratne. 1992. Coastal 2000: recommendations for a resource management strategy for Sri Lanka's coastal region, Volumes I and II. CRC Technical Report No. 2033., Coast Conservation Dept, Coastal Resources Management Project, Sri Lanka and Coastal Resources Center, The University of Rhode Island.

Pearce, D. 1991. Blueprint 2. Measuring Sustainable Development. Earthscan, London

Rajasuriya, A.; M.W.R.N. De Silva; M. C. Ohman. 1995. Coral reefs of Sri Lanka: human disturbance and management issues. Ambio V 25 No. 7-8 (428-437).

Walberg, P.; R. Johnstone. 1995. Diurnal variations in pelagic bacterial and primary production during monsoon and intermonsoon seasons: Puttalam Lagoon, Sri Lanka. Ambio V 24 No. 7-8 (418-422)

White A. T.; M. Wijaratne. 1989. Are coastal zone management and economic development complementary in Sri Lanka?

Wiyeratne, E.M.S.; U. Cederlof, L. Rydberg; K. Arulananthan. 1995. The tidal response of Puttalam Lagoon, Sri Lanka: a large shallow tropical lagoon. Ambio V 25 No. 7-8 (444-447)

Wanninayake, W.M.T.B.; A.A.D. Sarath Kumara; WV.F. Udaya. 1990. Settlement of oyster spat Crassostrea madrasensis (Preston) on four selected substrates in the Kala Oya estuary of Puttalam Lagoon, Sri Lanka. Proc. Inter. Interdisc. Symp. Ecology and Landscape management in Sri Lanka. Colombo, Sri Lanka 12-26 March 1990.

Wanninayake, W.M.T.B.; A.A.D. Sarath Kumara; WV.F. Udaya. 1990. Experimental studies on raft culture of oyster Crassostrea madrasensis (Preston) in Sri Lanka. Proc. Inter. Interdisc. Symp. Ecology and Landscape management in Sri Lanka. Colombo, Sri Lanka 12-26 March 1990.


Annex 1 List of Survey Department maps of the coastal zone of Sri Lanka
Annex 2 Field data collection form
Annex 3 FAO code of good practice for aquaculture

Annex 1 List of Survey Department maps of the coastal zone of Sri Lanka

Map list for 1:50,000 sheets covering the coastal area of Sri Lanka


Area Name




Point Pedro





































































Annex 2 Field data collection form

Site Location





District G.N.













Soil pH





Soil Texture


pyrite/clay loam

clay/to am

sandy clay

sandy loam

loamy sand


Vegetation/Land use


coconut plantation

rice fields in semi saline soils

salt tolerant scrub

wild life refuge/protected forest

sea grass w/Gracilaria

salt pans

saline ground water

User conflicts


small scale fisheries


wildlife and forest conservation

Access to infrastructure

distance to nearest paved road

distance to nearest 3 phase line

Salinity, ppt (annual range)






> 35

Nitrate, mg/l (annual range)



Nitrite, mg/l (annual range)




Ammonia, mg/l (annual range)




Hydrogen sulfide, mg/l




BOD, mg/l

< 10


Annex 3 FAO code of good practice for aquaculture

Aquaculture Development

Responsible development of aquaculture, including culture-based fisheries, in areas under national jurisdiction:

· States should establish, maintain and develop an appropriate legal and administrative framework which facilitates the development of responsible aquaculture.

· States should promote responsible development and management of aquaculture, including an advance evaluation of the effects of aquaculture development on genetic diversity and ecosystem integrity, based on the best available scientific information.

· States should produce and regularly update aquaculture development strategies and plans, as required, to ensure that aquaculture development is ecologically sustainable and to allow the rational use of resources shared by aquaculture and other activities.

· States should ensure that the livelihoods of local communities and their access to fishing grounds are not negatively affected by aquaculture developments.

· States should establish effective procedures specific to aquaculture to undertake appropriate environmental assessment and monitoring with the aim of minimize adverse ecological changes and related economic and social consequences resulting from water extraction, land use, discharge of effluents, use of drugs and chemicals and other aquaculture activities.

Responsible development of aquaculture including culture-based fisheries, within transboundary aquatic ecosystems:

· States should protect transboundary aquatic ecosystems by supporting responsible aquaculture practices within their national jurisdiction and by cooperation in the promotion of sustainable aquaculture practices.

· States should, with due respect to their neighboring States, and in accordance with international law, ensure responsible choice of species, siting and management of aquaculture activities which could affect transboundary aquatic ecosystems.

· States should consult with their neighboring States, as appropriate, before introducing nonindigenous species into transboundary aquatic ecosystems.

· States should establish appropriate mechanisms, such as databases and information networks to collect, share and disseminate data related to their aquaculture activities to facilitate cooperation on planning for aquaculture development at the national, subregional a, regional and global level.

· States should cooperate in the development of appropriate mechanisms, when required, to monitor the impacts of inputs used in aquaculture.

Use of aquatic genetic resources for the purposes of aquaculture, including culture-based fisheries:

· States should conserve genetic diversity and maintain integrity of aquatic communities and ecosystems by appropriate management. In particular, efforts should be undertaken to minimize the harmful effects of introducing normative species or genetically altered stock used of aquaculture including culture based fisheries into waters, especially where there is a significant potential for the spread of such non native species or genetically altered stocks into waters under the jurisdiction of other States as well as waters under the jurisdiction of the State of origin. States should, whenever possible, promote steps to minimize adverse genetic diseases and other effects of escaped farmed fish on wild stocks.

· States should cooperate in the elaboration, adoption and implementation of international codes of practice and procedures for introductions and transfers of aquatic organisms.

· States should, in order to minimize risks of disease transfer and other adverse effects on wild and cultured stocks, encourage adoption of appropriate practiced in the genetic improvement of brood stocks, the introduction of normative species, and in the production, sale and transport of eggs, larvae or fry, broodstock or other live materials. States should facilitate the preparation and implementation of appropriate national codes of practice and procedures to this effect.

· States should promote the use of appropriate procedures for the selection of brood stock and the production of eggs, larvae and fry.

· States should, where appropriate, promote research and, when feasible, the development of culture techniques for endangered species to protect, rehabilitate and enhance their stocks, taking into account the critical need to conserve genetic diversity of endangered species.

Responsible aquaculture at the production level:

· States should promote responsible aquaculture practices in support of rural communities, producer organizations and fish farmers.

· States should promote active participation of fish farmers and their communities sin the development of responsible aquaculture management practices.

· States should promote efforts which improve selection and use of appropriate feeds, feed additives and fertilizers, including manures.

· States should promote effective farm and fish health management practices favouring hygienic measures and vaccines. Safe, effective and minimal use of therapeutants, hormones and drugs, antibiotics and another disease control chemicals should be ensured.

· States should regulate the use of chemical inputs in aquaculture which are hazardous to human health and the environment.

· States should require that the disposal of wastes such as offal, sludge, dead or diseased fish, excess veterinary drugs and other hazardous chemical inputs does not constitute a hazard to human health and the environment.

· States should ensure the food safety of aquaculture products and promote efforts which maintain product quality and improve their value through particular care before and during harvesting and onsite processing and in storage and transport of the products.

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