Helene N. Chinivasagam
National Aquatic Resources Agency
I. INTRODUCTION
The total fish production in Sri Lanka in 1987 was around 190,000 MT while, total exports of fish and fishery products amounted to 2,417 MT. In addition to the 1987 national catch 7,740 MT of canned and 28,481 MT of dried/cured fish was imported to satisfy the increasing demand for fish which constitutes one of the major components of the local diet. Several species of crustaceans (crabs, shrimp, lobsters, etc.) and cuttlefish are the major marine organisms for export. Earnings in 1988 for frozen seafood amounted to Rs 627 million (1 US$= Rs 40). In contrast, the molluscan shellfish industry is still poorly developed although there is a great scope for further expansion in both the local and export markets. The extent of expansion would depend on various limitations pertaining to this industry, which otherwise could be of great economic importance to the country.
II. MAJOR MOLLUSC SPECIES AND THEIR DISTRIBUTION
A survey carried out by Fernando (1977) lists 32 species of bivalves of which 6 are edible. Among these only 2–3 species are regularly harvested in commercial quantities for local consumption and export. The major species and their distribution is shown in the table below (Fig. 1):
| Species | Distribution |
|---|---|
| Marcia opima (clam) | South Western, Eastern, Southern coast |
| Marcia hiantina (clam) | South Western, Eastern, Southern coast |
| Gafrarium tumidium (cockle) | South Western, Eastern, Southern coast |
| Perna perna (brown mussel) | Eastern coast |
| Perna viridis (green mussel) | Eastern coast |
| Crassostrea madrasensis (oyster) | North Western coast |
| Crassostrea belcheri (oyster) | North Western coast |
| Saccostrea cucullata (oyster) | North Western. eastern coast |
| Geloina coaxans (clam) | Eastern, South Western coast |
Figure 1. Recorded sites populated with commercially important molluscan shellfish in Sri Lanka.
Marcia spp. are the most popularly harvested species of molluscan shellfish as they are widely distributed along the Eastern and South Western coasts. They are harvested from natural grounds from April to June/July. The total harvest is not available, however it is estimated that about 15,000–20,000 kg of boiled product are harvested annually along the South Western region. Other species of bivalves are also popularly consumed in specific location, however they are not harvested for commercial purposes. Although mollusc culture, in the true sense of the word, is not yet practiced in Sri Lanka, its technical and economic feasibility is being investigated by the National Aquatic Resources Agency (NARA), particularly in the North Western, Eastern and Southern coasts of the country. Culture trials conducted by the Agency have produced promising results for culturing a number of selected species on a large commercial scale (Indrasena, 1987).
III. HARVESTING METHODS AND TRADITIONAL PROCESSING PRACTICES
As stated above the entire mollusc production in Sri Lanka comes from natural fisheries along the entire coastline. Most of the harvesting sites are located far from urban settlements and sources of industrial pollution. Rich grounds are also found near urban and industrial centres, however it is most likely that they are affected by contaminants and waste products from these centres.
The nature and distance of markets, and availability of ice and transport facilities determine the type of product processed at the harvest site. In most cases supply and demand are attributed to the marketability of the products and the availability of raw material at a particular time.
Harvesting is generally carried out manually by fishermen or members of their families at low tide. The bivalve gathered are then collected into boats and ferried ashore when the tide moves in.
Locally produced molluscan products
Mollusc are mostly boiled and boiled/dried, however, fresh products are also marketed.
| Boiled products: | Freshly collected mussels and clams (mainly Marcia spp.) are boiled directly in seawater and shucked. This practice is commonly carried out due to the convenience of handling and marketing a dried product. |
| Boiled/dried products: | Boiled molluscs are sun-dried and consumed as dried fish. Similar to the above, this form of processing is popularly practiced where marketing and transportation problems are encountered. |
| Fresh products: | Freshly harvested bivalves are sold directly to prospective processors with or without ice depending on its availability. Fresh shellfish are also sold directly to consumers located near the harvesting grounds. |
| Animal feed: | Boiled meat of a number of mollusc species is also used as shrimp feed in most farms. |
It has been observed that women play a major role in all stages of processing which is a fairly labour-intensive activity compared to the processing of most other fishery products. On average, one woman is able to produce 7–8 kg of shucked meat per day, earning about 800 rupees per month.
Products for the export market
The export of molluscan shellfish is at present carried out by a limited number of exporters already involved in trading crustaceans. The export of mollusc from Sri Lanka is a relatively new activity and the specifications of the product itself are dependent on the requests and needs of the respective buyers.
Molluscs are exported from Sri Lanka in two forms: frozen and canned. For the frozen products, the processors collect the shellfish from the usual harvesting sites either fresh or boiled. The shellfish are allowed to undergo self-purification in wooden barrels of seawater for at least 24 hours, after which they are boiled, shucked, packed into polythene bags and stored in ice. These operations are carried out on the shore next to the fishing villages and it is at this stage that the buyer collects and transports the molluscs to the processing plant. In other instances depuration is carried out in shallow cement tanks into which seawater is pumped from a nearby lagoon and changed at regular intervals. The shellfish are then transported live to the plant where they are boiled, shucked and cleaned prior to further processing. Ultimately the shellfish are frozen and packed for export. Although the above simple depuration practices are carried out, such activity is not carried out in an organized way either by the mollusc suppliers or the processors. With canned products, boiled molluscs are canned in brine or other canning media as specified by the buyers. The export of canned mollusc is a relatively new activity and only limited quantities have been exported before 1986.
IV. SANITARY MEASURES AND OTHER PRACTICES TO MONITOR AND ENFORCE QUALITY CONTROL
Since molluscs are almost entirely harvested from natural beds, which may or may not be subjected to environmental or industrial pollution, the product harvested may face certain sanitation problems. It must be mentioned however that all local mollusc preparations are subjected to traditional cooking which usually generates a heat level sufficiently strong to destroy most bacterial pathogens.
In Sri Lanka there is a limited control with regard to the quality of the growing sites and the harvested product. This is mainly due to the non enforcement of sanitary standards for most of the local fish and fish products as well as the absence of an established export industry as the one existing for crustaceans. The Sri Lanka Standards Institution and the National Aquatic Resources Agency are concerned with the enforcement of quality standards for all crustacean exports due to competition in the export market and to maintain the reputation of the country's export industry. Thus the expansion of the mollusc culture and processing industry as a response to an export activity would ensure the enforcement of practice codes and standards.
Studies are now in progress at NARA to ascertain the distribution of selected indicator organisms and pathogens in some commercially important bivalves.
V. MARKETING AND DISTRIBUTION OF MOLLUSCS
Molluscs are commonly marketed under some kind of processed form, particularly when they are distributed to rural or urban areas at some distance from the growing beds or when they are aimed for the export market. A rather small proportion of the harvest is retailed fresh or iced in localities adjacent to the fishery grounds. Retailing is carried out by small-scale vendors or intermediaries who collect and market the processed products to small towns and cities.
Most shellfish products are consumed in coastal areas near production sites. Molluscs, in general, have not gained wide popularity among Sri Lankans unlike fish and crustaceans. The limited supply and the seasonal availability may be partly responsible for this situation. In addition to human consumption, boiled mollusc meat is now being used as feed for cultured shrimp.
Local market. The local marketing pattern usually involves an intermediary who collects the products and distributes them to local and/or urban markets. The boiled/dried product, and to a lesser extent, the fresh unshucked product are the major market product forms. The boiled/dried product is retailed at around 45–108 rupees a kg and it is particularly demanded in rural/urban areas close to the sites of production. For some ethnic group these products are delicacies. The harvesting and marketing of molluscs is generally carried out by fishermen who are involved in the more lucrative local fish and crustacean export industry. One basket (approximately 1 kg) of freshly harvested molluscs is sold at Rs 5–10/kg depending on species. The boiled product prepared as shrimp feed fetches around Rs 20/kg. Most cottage scale producers earn an additional income from the sale of shells which are sold at around Rs 9/kg. Mollusc shells constitute an independent industry as a whole and in some cases the edible part of the mollusc is allowed to decay while only the shell is retained and utilized.
Export market. The export industry was first established in 1987 when crustacean processors began to export molluscs. Such industry in Sri Lanka is limited mainly due to the unreliable supply of raw material whereby the exporters find it difficult to fulfill their order requirements. The boiled product is purchased at about Rs 18/kg. It has been reported that the buyers are particularly concerned with product quality and are therefore very cautious in placing orders.
In spite of these limitations Sri Lanka exported 26 MT in 1987 and 5.6 MT of molluscs in 1988, earning a total revenue of Rs 3.9 million and Rs 1.6 million, respectively. Major markets for the frozen and dried products are Japan, USA, Hong Kong and the Maldives. As mentioned earlier a steadier export market could be established with the development of a culture industry backed by an enforced sanitary programme. Until then the Sri Lankan mollusc export industry will remain at an elementary stage.
VI. FUTURE OF THE MOLLUSC INDUSTRY IN SRI LANKA
The future expansion of this industry greatly depends on a demand increase for the export market and as feedstuff for the shrimp culture industry. Such expansion would also be facilitated by the development of the culture industry itself. Local consumption could be increased through more promotion and marketing to encourage the consumption of molluscs as a valuable protein source. Thus with potential for further development of this industry in Sri Lanka, great emphasis should be placed on monitoring and enforcing sanitary conditions in the culture, harvest and processing stages, as seen in the crustacean industry. Needless to say, with the development of the industry such measures would naturally be implemented. This would ensure a steadier market and more attractive returns to the producer and to the industry. The Sri Lankan government is supporting and promoting the fishery export industry as a means of earning valuable foreign exchange, and therefore it is likely that the mollusc industry will receive increasing attention in the future.
BIBLIOGRAPHY
Fernando, D. H. (1977). Lamellibranchiate fauna of the Estuarine and Coastal Areas in Sri Lanka. Bulletin of the Fisheries Research Station, Ceylon, vol. 27, 29–54.
Indrasena, W. M. (1987). Mollusc Culture Project. Technical Report. National Aquatic Resources Agency, Colombo, Sri Lanka.
