Pollution is increasingly becoming a serious threat to the fishing industry in the South China Sea area and coastal aquaculture sites are usually the first affected. Some countries have passed rigid anti-pollution laws and regulations, but there is a general lack of information that could serve as bases for rational action, especially in already seriously affected areas. Preliminary studies have been made (Lesaca 1972, Rabanal and Datingaling 1973, Thorslund 1972), and some information has been gathered recently in the participating countries of the South China Sea Programme.
Some aquaculture developments near population centres in Java were affected by pollution and had to be adandoned; a brackishwater experimental station was closed.
Pollution of fishpond areas, swamps and inland waters has been attributed to the use in adjacent fields of highly potent pesticides used in the control of rice pests. Studies on the effects of these pesticides on fish are now being conducted at the Inland Fisheries Research Institute at Bogor. The Indonesian Government has shown great concern and has issued a presidential decree prohibiting the use of pesticides found to be most noxious to fish.
Some inland fish culture has been developed, but very little coastal aquaculture. Danger from pollution is small.
Pollution from industries has affected existing and potential coastal aquaculture sites. A highly productive, extensive tidal flat in West Malaysia, used previously for the culture of cockles (Anadara granosa), had to be abandoned. A wide area of mangrove swamps which could be used for brackishwater fish or shrimp ponds in the southern part of Western Malaysia has been rendered unfit by pollutants from a fruit canning factory. Undoubtedly there are other areas similarly affected, since industry is reported to be developing briskly.
Both sewage and industrial pollutants have affected coastal aquaculture in this country. The centre of the Chanos nursery ponds, consisting of nearly 200 ha located north of Manila, was forced to move to other parts of the country by pollution from breweries, chemical plants and sewage. A government experimental farm and other sites along river mouths and creeks where mining establishments discharge operational wastes are similarly affected. Many such areas are suitable for the development of estuarine fish/shrimp ponds. Litigation on these pollution cases are not uncommon, with the National Water and Air Pollution Control Commission providing the technical and administrative arm of the government.
The collecting grounds for the Chanos fry in southern Philippines are being threatened by pollutants from lumber sawmills. The Philippine Bureau of Fisheries has been conducting investigations in these areas.
Land reclamation has seriously affected the expansion and even the continuing maintenance of aquaculture sites in Singapore. Rapid industrialization has caused spectacular rises in the price of land, and reclamation interests have taken the upper hand. Although the government continues to support projects for the production of fish and other fishery products through aquaculture, production will be confined to highly-priced species (Macrobrachium, Penaeus, Anguilla, Epinephelus, Oxyleotris, etc.). The government is well aware of the dangers from pollution in the coastal areas and has issued very strict control regulations embodied in The Prevention of Pollution of the Sea Act, 1971.
Pollution from population centres and from industry has severely affected the south central part of the country. The Chao Phya River carries domestic and industrial effluents from Ayudhaya in its upper reaches and from Bangkok-Thonburi just before it reaches the sea. The Mae Klong River is also highly polluted by organic industrial wastes, mainly from the sugar factories located along its course. The lower reaches of these rivers are important reproduction and nursery grounds for the fish and shrimp population of the inland and coastal waters. Fish and shrimp farms and potential sites for this type of farm have been reported to be badly affected.
Control of water pollution in Thailand is chiefly the responsibility of the Ministry of Industry, but its facilities are limited. The Ministry of Public Health is also responsible, particularly with respect to sanitation and public health. The Department of Fisheries, which is under the Ministry of Agriculture, has recently become involved in the problem of water pollution, but its facilities are inadequate for the work required. It is apparent that there is a need for a coordinating agency.
Due to rapidly increasing population and urbanization, Hong Kong is faced with a major pollution problem. The large areas of tidal flats and bayous along the northeastern coast that formerly were beds for extensive oyster culture have been abandoned. Search for new sites has been futile. The outlook is improved since pollution is largely from organic substances and there are no big industrial developments, and the country's proximity to the open sea alleviates the situation.
The use of powerful polluting agents in the execution of war has become a threat to certain fishery areas. Fortunately, the extensive water bodies serve to dissipate pollutants and damage does not seem too great so far. The danger from pollution will increase with the population and industrialization of the country. Appropriate safeguards should be raised now against irreversible effects.
