by
Dr. Kitja Jaiyen
Fisheries Policy and Planning Division
Bangkok, Thailand
Aquaculture, although contributes a relatively small portion, about 8% in tonnage, to the total fish production of Thailand, has a potential, in a long term, of increasing fish production for local consumption and could make a major contribution to export earning from high value shrimp and fish species. It has shown slow but steady growth during the past several years. Total production in 1983 was 174,098 mt from a net water surface area of about 480,000 rai. of his total, 65 per cent was mariculture production of bivalve and molluscs, 26 per cent was produced by freshwater aquaculture, and the rest was shrimp, fish and crabs produced in brackishwater ponds.
1. Bivalve Mariculture
In 1983 115,582 mt of bivalve molluscs were produced from 18,960 rai of culture area in the coastal waters of Thailand. Cultured species include bloody cockly (Anadara granosa), green mussel (Mytilus smaragdinus), oysters (Crassostrea commercialis and C. luqubris) and horse mussel (Modiolus senhausenil). Most other bivalve landings are collected from wild stock. DOF data indicate, since 1981, a trend towards a recovery in production. Based on DOF's emphasis in promoting bivalve mariculture and the external aid provided by ICLARM and the Federal Republic of Germany, it is likely that bivalve mariculture will continue to expand at a rapid rate.
The data suggest that Thailand has another 239,000 rai of coastal area that is suitable for development. If annual growth rate equal to 10 per cent of 1982 levels is maintained, it is projected that total production in 1991 will be 215,000 mt from about 41,000 rai.
However, in order to develop coastal resources effectively, conflicts between different sectors for land and water use must be minimized through a better comprehensive coastal zone management plan and to remove the problems of water pollution and seed stock limitations.
2. Freshwater aquaculture
Freshwater aquaculture composes of the following 4 main practises.
2.1 Freshwater Pond Culture
There were 52,247 rai of freshwater fish ponds in 1983, distributed among 28,942 farms with 42,662 ponds. The average farm had 1.5 ponds with a net production area of 1.84 rai. Total production from pond culture in 1983 was 26,071 mt. The main species cultured were catfish (Panqasius spp. and Clarias spp.) with 6,739 mt and 2,743 mt respectively, Nile tilapia 5,783 mt snakehead (Opiocephalus spp.) 3,813 mt and Thai carp (Puntius qonionotus) 3,395 mt.
Average production from pond culture in Thailand is 499 kg/rai with a range of 209 kg/rai in the Northeastern Region to 496 kg/rai in the Western Region. The high productivity of fish ponds in Western Central Region is due in part to the intensive culture of snakehead and Clarias spp. catfish in Suphan Buri Province where 10 per cent of total national production from freshwater ponds, (2,645 mt) is produced in 7.947 rai of ponds, of which 86 per cent is for raising giant prawn. However, during the past few years, fish disease problems have been experienced in and around Suphan Buri Province with reported losses in 1982 of about 300 million worth of cultured fish. There are several theories but most scientists studying this problem relate it to stress caused by water pollution, by low alkalinity in the water supplies and by the high stocking denstities of fish in the ponds. Some farmers are reported to attempt pond carrying capacities of 6 to 10 mt per rai.
It is estimated that the construction of ponds throughout the country will increase by 15 per cent annually over 1982 levels. Therefore, national annual production from freshwater ponds is expected to reach 73,500 mt by 1991.
2.2 Freshwater Cage Culture
There were about 600 cage culture farmers that produced 326 mt of fish from 1,230 cages in 1983. The total production area was about 45 rai, with an average output per square meter of 4.5 kg. This represents a marked decrease from 1982 figures when 625 farmers produced 324 mt from 1,170 cages with a total production area of 14 rai. Average productivity in 1981 was 14.9 kg/m2. The primary culture species were Panqasius spp. catfish and sand goby (Oxyeleotris marmoratus) The production from cages decreased from 1982 to 1983, mainly due to the fish disease in 1982.
2.3 Rice cum Fish Culture
Fish production from paddy fields totalled 19,697 mt in 1983. Net area under production was 185,450 rai in that year as compared to 130,800 in 1978 when 21,300 mt were produced. The primary species cultured are Puntius spp. tilapia and common carp.
There are no clear growth trends in paddy fish culture activities. This culture practice requires careful administration of low levels of insecticides and herebicides this is at odds with current trends to use high-yielding rice strains which require heavy application of pesticides. Although this culture practice is theoretically quite cound and is an attractive integration of farming and fish culture that appeals to technicians, local farmers are less enthusiastic and culture output is expected to remain at about 1982 levels in the foreseeable future.
2.4 Ditch Culture
A variety of fish species are cultured in irrigation ditches throughout Thailand. Culture practices vary and are generally not a well developed subsector. Total production in 1983 from 1,692 rai was 872 mt, slightly increase from 640 mt in 1982.
3. Brackishwater Pond Culture
There were 192,453 rai of brackishwater ponds and 3,943 family farms. Total production was 11,590 mt, of which 99 per cent consists of shrimp. Thailand's shrimp farmers were early to recognize the economic advantages of using pumps to fill, stock and exchange water in their ponds. The area of ponds under culture has been growing at an average annual rate of about 9 per cent since 1980.
The principal species cultured are banana shrimp (Penaeus merquiensis), school shrimp (Metapenaeus spp.) and jumbo tiger shrimp (P. monodon). Current culture practices are limited by an inconsistent and seasonal supply of wild P. merquiensis fry and a shortage of the more valuable P. monodon fry and other constraints, i.e, limitation of existing ponds, water pollution. etc. To reach a production target of 68,000 mt by 1991 will require a rapid expansion of the shrimp hatchery capacity, as well as capital investment by farmers to build new ponds, upgrade their existing ponds and facilities and to purchase seed and supplemental feed.
AQUACULTURE DEVELOPMENT PLAN
1. Freshwater aquaculture development plan has an objective to produce high value fish, mainly, for local consumption, with some exceptional species, e.g. sand goby, and also giant freshwater prawn for export. This plan places emphasis in producing fish seeds, which are self-propagating and fast growing species, enough to supply the aquaculturists, and conducting propagation scheme to increase fish production. Accordingly, the activities will include: research and experiment on genetic improvement of cultivated species; Identification of diseases and parasites; establishment of effective measures to control and prevent these diseases; and transfer technical know-how on aquaculture technique to those who are interested in culture practises in order to improve their business more efficiently.
2. Brackishwater aquaculture since the brackishwater aquaculture development will emphasize on the culture of penaeid shrimp of high foreign market demand. it will be aimed, mainly, for export. This plan emphasizes in extending the cultured coastal areas. The activities will include: research and experiment on culture technology and fish nutrition: identification and prevention of fish diseases and parasites; and extension the culture technique to those who are interested so as to attain the maximum output. In the long run, the exploration of coastal resources and environment will be carried out along the coast of Thailand in order to classify the possible culture areas. Exploration and research on water pollution will also be conducted in order to set up the effective measures to prevent and control the problems occuring to the coastal resources.
3. Marine culture this plan stresses promotion and expansion of marine fish and mollusc culture in order to replace fishing occupation along the coastal area which tend to be worsen because of over-fishing. Its production will be consumed locally and exported. Accordingly, the activities will include research on life history seed production and culture technics, establishment of training center for aquaculturists. Furthermore, the development of small scale fisheries is major concern in order to improve the living standard of fishermen resided along the coast of Thailand.
The targets are to produce fish seeds not less than 38 million within five years, cultured marine fish not less than 1,000 tons and 500 coastal fishermen will be promoted to engage in marine fish cage culture.
The growth rate of total production from aquaculture is projected at 2 per cent annually or to reach 329,000 tons in 1986. Of which 231,375 tons are contributed by freshwater fish culture.
