SRI LANKA

Although bivalve resources have been reported to be considerable in the coastal waters of Sri Lanka, bivalve culture is still at the experimental stage. At present, the National Aquatic Resources Agency (NARA), partly supported by the International Development Research Centre (IDRC), is the main governmental agency involved in the applied research of mollusc culture in the country.

A considerable number of edible oyster species has been identified by the agency, however research work is mostly concentrated on the large oysters Crassostrea madrasensis and C. belcheri and on the smaller Saccostrea cucullata. Other bivalve species which are receiving considerable attention as potential aquaculture candidates include the mussels Perna viridis, P. perna, the cockle Gafrarium tumidum and the clams Marcia opima and M. hiantina.

Although this kind of food is not particularly popular among Sri Lankans, increasing numbers of fishing families involved in deep sea fishery turn to bivalves during the monsoon seasons and in some areas during peak tourist seasons.
These protein-rich organisms are usually salted and dried and sold in the areas where the resources are plentiful. An export-orientated industry for some bivalves in some areas of the country has just started (Indrasena and Wanninayake, 1986).
A series of on-going experiments on the culture of the above mentioned species has shown that these organisms can be successfully cultured in numerous locations along the coastal waters of Sri Lanka. With the introduction of culture methods for the Indian large oyster (C. madrasensis) in 1982, this oyster has become particularly popular among people around the culture areas.
No information has been made available on the distribution of natural mollusc fisheries in Sri Lanka. It is believed that both C. madrasensis and C. cucullata are found throughout most of the Island's coasts. According to the limited information available important oyster grounds and culture areas occur in Trincomalee Bay on the East coast, Kalpitiya on the West coast and in several localities in the Southern Province. Natural beds of the brown mussel P. perna are mainly distributed along the coast going from Chilaw to Hambantoka. The clams are also believed to be widely distributed along the entire coastline, however important natural beds have been detected off Kalipitiya and Trincomalee Bay.

Mollusc production figures in Sri Lanka are not available. It is presumed that the annual landings are relatively low due to the overall lack in popularity of molluscs as a food item as well as the virtually non-existent export market. However, the combined landing for the cockle (G. tumidum) and the two clam species (M. opima and M. hiantina) reported for 1987 amounted to 10,820 Kg (Table 1).

The mollusc industry in Sri Lanka is currently facing all the typical constraints of establishing a culture system previously non-existent in the country. Very little information is available on the natural distribution of edible species, spatfall seasons and suitable culture techniques. In addition, there are very few trained personnel (Table 2).
Although oysters and other bivalve species are gaining popularity among small fishing communities, it is generally a food item not highly accepted.
Culture experiments on C. madrasensis, P. perna and P. viridis being conducted by NARA are facing problems due to the limited supply of seed. The above situation is probably due to the lack of experience in seed collection by the personnel involved.

Table 1: Annual production of commercially important shellfish in Sri Lanka, 1980–1986. (Values: Kg).

Due to the rich resources of bivalves, especially oysters, in certain coastal areas and lagoons of the country, considerable effort is being channelled towards the collection of required biological and environmental information (i.e. culture site selection, culture methods, spat collection timing, etc.).
The technical staff of the National Aquatic Resources Agency is the only group currently active in the field of applied mollusc culture research. The on-going experiments on oyster and mussel spat collection and culture carried out by the Agency have produced encouraging results. But much more research is required.

Table 2: Information on status of mollusc culture in Sri Lanka.