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4. Invited papers and discussions
Socio-economic aspects of brackish-water fish
culture in southeast Asia in comparison with the aquaculture
system in Japan
Buginese colonization of sumatra's coastal
swamplands and its significance for development planning
S. Iwakiri
Recently, interest has been growing in many Southeast Asian countries in the importance of inland fisheries. One of the main objectives of this interest is to have self-sufficiency in protein in the local food supply. But it has been observed that there is insufficient knowledge about the socioeconomic aspects of inland fisheries in the Southeast Asian countries. So here I would like to explain the relationship between inland fisheries and the rural socio-economic pattern.
Inland fisheries in Southeast Asia can be classified roughly into two categories. These are fresh water fisheries and brackish-water fisheries, each of which includes fish culture and fishing. At the present stage, the fresh-water fisheries in lakes, reservoirs, rivers, and paddy fields are the main sources of fresh water fish for the farming villages. On the other hand, brackish-water cultures are operated in manmade ponds and swamps near the coast, and have been developed in the Philippines, Indonesia, and Thailand. These brackish-water cultures are unique because they perform the role of a mass-production system, resembling an enterprise management system in each rural society.
In the case of Thailand, where it is a traditional technique, tiger-shrimp culture has been developing for more than several decades. In the Philippines and Indonesia, with a background of about 200 to 400 years, the milk-fish (chanoschanos; in Taiwan, sabahi) culture is practiced by releasing the fingerlings into the brackish-water ponds. In the early 1970s the area of fish culture ponds was 150,000 ha in the Philippines and 170,000 ha in Indonesia.
First, I would like to describe the ownership of fish culture ponds in Indonesia and the Philippines. Where brackishwater fish ponds are located in urban areas the approved land prices are estimated in terms of units of a hectare per dealing. These fish-culture ponds are owned mainly by merchants, especially the overseas Chinese merchants who live in urban areas and a few other owners living in the country area. Most of the ponds located in rural areas of sparse population are government owned rather than privately owned, but some of them belong to the military authorities or bureaucrats. This is because of the imperfection of the personal possession system. It is not uncommon to find that in remote sections where the brackish-water ponds are located in naturally swampy or marshy areas, such ponds are being treated in units of 1 0,000 ha.
Only a few ponds are managed by their owners; most of them are run by absentee owners. Also the ownership registration can be leased or sold. The actual control and operation of fish culture is often contracted with the supervisor, who is an experienced manager of fish ponds. The responsibility of the supervisor is to repair and rebuild the ponds, buy fish fry, manage fish culture, and harvest the fish for sale. He shares the profits with the owner according to his contract. Usually a change in ownership by sale or lease does not call for any change of supervisor.
Almost all the owners of the self-managed ponds are overseas Chinese merchants. Recently, however, selfmanagement is increasing gradually among the local landowners. This tendency should contribute to the increase of commercial profits by improved efforts through capitalintensive management. Productivity is rising and the harvest of milk fish ranged from 300 kg/ha to 10,000 kg/ha in the various ponds. However milk fish is originally categorized as a high-class fish, due to its popularity as a food, and fishculture pond management offers a profitable type of business in primary industry. It is observed that the value of purchases and leases rises with the technical progress of pond construction as well as the rationalization of fish-culture technology.
Labourers are employed at a rate of one person per hectare pond area on a time basis. Full time employees are very few, a large number of neighbouring farmers being employed in the traditional working system of pond operation, which is organized particularly during the fish harvest and pond renovation seasons. Workers employed are controlled entirely by supervisors and are not affected by changes in pond ownership.
The activities of the fish-pond culture have influenced greatly the economic aspects of local community life, because the managers of ponds purchase materials necessary for their operations from the locality. Also, the local inhabitants employed as part-time workers are freely supplied with miscellaneous fish.
Recently, there have been suggestions that tiger-shrimp culture be introduced instead of milk-fish culture. It may be useful in suitable locations to change milk-fish to tiger shrimp through a capital-intensive technique. But if we consider the relationship between the traditional fish ponds and the economy of the rural communities, it becomes obvious that the introduction of a too intensive fish culture might lead to confusion. In view of the above, it should be considered that an increase of fish-pond productivity will be achieved by the application of ecology to the existing system of fish culture.
The Indonesian tambak productivity, or annual harvest of milk fish per 1 ha of tambak, is lower than that of the Philippines-approximately one half on average. This is because tambak are operated on a large scale in the Philippines, and owners are eager to introduce new technology to their ponds, while in Indonesia small-scale tambak operation still prevails and most of the owners live away from their ponds, leaving the management to employees who tend to make little effort to improve technology. This difference, in my opinion, accounts for the vast gap in production volume between the two countries.
Although tambak are being developed at a tremendous rate in the Philippines through large-seala machine deforestation of mangrove trees along with the promotion of artificial feeding and mixed culture, all of which certainly help improve productivity, these methods also do great harm to the ecosystem and environment. This is exactly why interdiseiplinarity in science and technology is important for tambak development.
In discussing the coastal zone of Indonesia, I shall first mention the wide coastal zone of North Sumatra which is still undeveloped. This coastal zone is lacking in many facilities like water and electric supply, a transportation system, and river flood control measures; it has a humid climate and muddy, swampy soil. This type of environment is unfavourable for development.
Considering the problems faced by each coastal zone, a practical approach for coastal utilization should be adopted. Tambak, brackish-water fish culture in the coastal area, could be the most practical, providing attention is paid to keeping a proper balance with the biological ecology.
The historical fish-culture system, with naturally grown plankton and grass food produced by the management of the biological ecology of wetlands, will provide an effective fish culture at low cost. Second, avoiding artificial feeding systems, food can be provided through culture of plankton, using feedback and other transformation techniques. By the way, recently in Japan there has been an excessive cost involvement in shallow water fish culture by artificial feeding. In the case of sea bream and yellow-tail fish culture, to produce a fish of 1 kg requires food materials equivalent to 7 kg of fish, which is more than 60 per cent of the production cost. Moreover the cost of making frames, nets, and other accessories makes the system uneconomical.
During the collection of an artificial supply of food, fish like mackerel, sardines, and so on are caught for a regular food supply, but the ecology systems are noticeably unbalanced, and the fingerlings of yellow tail and sea bream have been reduced as a result of over-fishing and disturbing the growth of marine resources. The generation of these fish varieties is drastically changed, which could mean a loss of potentially valuable edible marine resources.
It is also found that in the case of shrimp culture the construction work for regulating a clean water supply and other auxiliary facilities makes the investment cost higher, resulting in the market price becoming undesirably high. As such investments are unavoidable in fish culture, the prime need is the introduction of a high productivity system without the costs due to the provision of an artificial food supply; that is, a natural environment must be created for growing fish food within the culture system.
A further problem is water pollution, which has become alarming in Japan. The Japanese government's policy of rapid industrialization and high economic growth has contributed to the pollution of the nation's fishing waters. Industrial pollution greatly reduced Japan's marine resources in the 1960s, and after 1970 people began gradually to get interested in pollution problems. By this time, however, various kinds of deformed fish had been found in over 300 places throughout Japan. A report published by the Ministry of Health and Welfare in 1973 concerning mercury and PCB contamination in offshore waters caused a national uproar.
The water pollution is attributed mainly to industrial effluent, household waste, and wastes left over from artificial fish feeding, as well as the accumulation of fish excretion. Red tides resulting from water pollution have occurred off some parts of Japan, especially in Setonaikai, where a large aquaculture field has been spoiled, leaving no possibility of fish production in that area in the near future.
Aquaculture has also suffered from water pollution in Japan. Pollution risks should be carefully checked in other countries with this kind of fish culture so that eutrophication problems due to the supply of artificial food do not arise.
Thus it is clear that for different reasons the experience from the capital-intensive aquaculture system in Japan has not been encouraging. In seeking to develop aquaculture by the tambak system in Indonesia, emphasis should be given to the management of natural biological production as a basis for fish culture, a technique which requires much less capital and results in the improvement of the biological ecology of the environment rather than pollution and spoliation.
It was observed in some Asian countries that where a highcapacity machine brought from Japan was used to construct ponds for shrimp culture, the results were ultimately found to be unsuccessful. This type of investment in large scale mechanization is not only a waste of money, but also a fruitless effort; it is a misuse of resources which could be better utilized for improving the natural biological ecology for fish culture.
Discussion
Sujastani: In what way was the machinery imported for pond construction unsuccessful?
Iwakiri: It was ecologically damaging; it caused excessive disturbance of the ecological systems.