The oyster industry in the selected Asian countries are facing similar constraints most of which are strongly interrelated. The pollution of oyster on-growing sites is one of the major problems of the industry today. Apart from some of the most developed countries in the region, only few industrial plants in the region have waste treatment facilities often partially operated due to high operating costs. In the Philippines for example the traditional oyster grounds in Manila Bay and Cavite are being severely polluted by industrial wastes. One serious and lasting impact of pollutants on the shellfish industry is on the seed supply situation, as bivalve larvae are acutely sensitive to even low levels of industrial wastes.
A further constraint which is affecting oyster mariculture in
many areas of the region is the undependable seed supply. Oyster
culture depends solely on the availability and abundance of wild
seed supply. Although natural seed supply has generally been
sufficient to support the minimal needs of the industry, the
recent irregular spatfall seasons and insufficient spat supply
have made the supply of wild seed increasingly unreliable for
maintaining present production levels or for increasing
production output through seafarming practices. The reduction of
the traditional seed collection grounds is also rapidly
decreasing owing to pollution and competition of the grounds for
other uses.
The poor sanitary quality of shellfish in general is another
serious problem of the oyster industry. Increasing incidences of
food poisoning, gastro-enteritis and hepatitis in the region,
especially in the most southern of the selected countries have
been attributed to the consumption of contaminated bivalves.
This has been one of the major reasons for the low consumer
acceptance and limited export market. Many of these countries
are now doing research on depuration as an answer to the
sanitation problems.
Other major problems related to oyster production are: 1) lack of standard criteria for selecting sites for shellfish farms; 2) lack in conservation and regulatory measures and 3) threat of poisonous shellfish due to toxic red tides or other shellfish toxins. Problems related to marketing have been identified mainly to be: 1) inadequate processing and packing systems; 2) lack of product-development efforts to produce innovative product forms to win new markets, and 3) limited market demand and low prices. The above constraints generally prevail in most of the countries under consideration. However, the more developed countries such as the Republic of Korea are certainly ahead of other South East Asian nations in dealing with these constraints.
Other problems that need to be solved are related to the culture practices themselves. Although each country has adopted one or more culture methods in order to suit its own coastal environments, it is generally felt that transfer of culture technologies should be aided so that each country can introduce or further develop new and existing culture systems respectively. Spatfall-forecasting techniques deserve particular attention particularly in tropical environments where the breeding season frequently extends over several months.
One last constraint within the oyster industry which is particularly affecting countries like Sri Lanka, where the industry is still young, is the lack of qualified technical personnel and trained extension workers.
Security of tenure of bivalve on-growing areas is important in encouraging ventures in mollusc culture. In many of the selected countries current legislation for leasing culture grounds is minimal, and regulations must be considered in the future.
Because of the reproductive capacity and high growth rates of most bivalves in the tropics, they are a food resource that cannot be ignored. While there has been considerable utilization of the resources in the region, their full potential has yet to be realized in most of the countries.
