Development and directions in milkfish (Chanos chanos ) research in the Philippines from 1976 to the present are reviewed and analyzed. The problems of milkfish culture are dichotomous: low productivity vis-a-vis seasons of glut and price fluctuations. To intensify fish production extensive research has been conducted on fertilizer management, reclamation of acid sulfate soils, and pond construction and engineering. Research efforts have also been heavily directed toward increasing fry production through artificial propagation, improvement of fry collecting gear, and increasing fry survival through nutrition, control of parasites, and proper handling. Research on improved icing, packaging, and processing techniques along with market analysis are necessary for maximizing economic returns.

The induced breeding of milkfish (Chanos chanos ) has been attempted by many institutes in the Philippines, Taiwan, Tahiti, Indonesia, and Hawaii. So far, a few successful trials have been achieved only in the Philippines and Taiwan, although different sources of spawners were used. In Taiwan the spawners used were reared from fry to sexual maturity in ponds and concrete tanks. This paper summarizes the gonadal development of captive milkfish at various stages of sexual maturation investigated from 1975 to 1980 and describes three successful trials of induced breeding in 1979, 1982, and 1983 in Taiwan. Finally, the problems that need further study are discussed.

This paper presents all known parasites of milkfish (Chanos chanos ) in the Philippines. The major parasitic groups include acanthocephalans, copepods, isopods, and heterophyid flukes. The number of parasitic species found in ponds is small compared with those harbored by the fish in its natural environment. Parasites with a direct life cycle usually survive in ponds as flagellates, ciliates, myxosporidians, coccidia, and parasitic arthropods under improper management. The methods of treatment, prevention and control of these parasites are discussed.

Historically, milkfish (Chanos chanos Forsskal) has been the premier aquaculture product in Indonesia, the Philippines, and Taiwan. However, there are significant differences in the industry's performance among and within these places, especially in terms of yield. These differences can be explained by different factor (land, labor, capital) endowments and by the fact that producers have generally been responsive to these conditions. In Taiwan and the Philippines, milkfish production is becoming less profitable over time. In both places, brackishwater pond producers of milkfish are caught in a cost-price squeeze as input costs have increased more rapidly than market prices. Indonesian producers also face market constraints because high regional transport costs often isolate them from major market centers. In response to declining profitability of milkfish, producers have been changing their production techniques and shifting to the culture of other species such as tilapia that currently have greater domestic or export market potential. Although total milkfish production continues to increase, in the Philippines and Indonesia at least, milkfish's traditional share of total aquaculture production in all these places has declined quite dramatically over the last 10 years, and this trend is likely to continue.

A special workshop among participants was conducted to assess the status of the aquaculture industry in Southeast Asia, particularly in Malaysia, Philippines, Singapore, and Thailand. Although hatchery, nursery, and grow-out culture techniques had already been developed for most of the economically important species cultured in Southeast Asia, the outcome of the workshop showed that there are still major constraints to be able to increase production. Further studies have to be conducted to have greater control of factors that lead to better production. The participants prioritized the economically important species and the research area for each species for the Region.

The aquaculture sector of the Philippine fishing industry registered the highest growth rate of 12.5% in 1977-1986. The contribution of aquaculture to the total fish production was equivalent to 24% in 1986 compared to only 85 in the early 1970's. In terms of quantity, the mariculture subsector registered the highest growth rate of 10.2% in 1982-1986, whereas in terms of value the brackishwater fishpond subsector showed the highest growth rate of 33%. Meanwhile, freshwater aquaculture production exhibited a negative growth rate due to reduction of activities in Laguna de Bay and the slow expansion in hectarage of the commercial freshwater fishponds. Research by several agencies concentrated heavily on the culture of milkfish (Chanos chanos), tilapia (Oreochromis niloticus), Chinese carps (Aristichthys nobilis and Hypophthalmichthys molitrix), tiger prawn (Penaeus monodon), and sea bass (Lates calcarifer). Innovations in seaweed, oyster, and mussel farming are also discussed. Research directions are presented to assure an ecologically sustainable growth in aquaculture with emphasis on countryside development.

The trend of fish production in Singapore is towards increasing contribution from marine and brackishwater aquaculture. Aquaculture production in 1986 represented 6.8% of local fish production. It is envisaged that this sector will provide about 37.5% of production by 1995. Freshwater aquaculture will focus mainly on production of ornamental fish. Production from farming of freshwater food fish is not likely to increase significantly. Commonly farmed marine finfishes are groupers (Epinephelus tauvina), sea bass (Lates calcarifer), and golden snapper (Lutjanus johni). Crustaceans include prawns (Penaeus merguiensis), crabs (Scylla serrata) and mussels (Perna viridis). Of the freshwater finfishes, the most commonly cultured are the grass, silver and bighead carps, red tilapia (Oreochromis niloticus hybrid), Lampam jawa (Puntius gonionotus), marble goby (Oxyleotrix marmorata) and the snakehead (Channa sp.). Aquaculture systems use a combination of floating and shorebased techniques. Earthen ponds are utilized for the culture of freshwater carps, floating netcages for marine finfish, ponds and floating netcages for marine crustaceans, and rope culture for mussels. Some research and development studies conducted presently include maturation studies to solve the problem of inconsistent supply of prawn spawners, experiments or use of dry formulated feed to do away with dependency on trash fish as main feed for grow-out marine finfish, and investigations on diseases of prawns under intensive culture. Constraints for large-scale production of finfish seeds lie in the large tank facilities required for producing live feed; for nursery operations, time and manpower required for grading and feeding; for growout systems, disease prevention and control; for prawn production, inconsistent spawner supply; and for mussel production, low consumer demand. The species with the highest potential for fanning in Singapore is the banana prawn, Penaeus merguiensis as its culture can be intensified and high yields can be obtained.

With training as one of its three mandated functions, the SEAFDEC Aquaculture Department offered its first training course in 1974. Since then it has trained some 6 519 participants in various degree and non-degree programs. The degree courses are MS. Fisheries (Aquaculture) and M. Aquaculture in collaboration with the University of the Philippines in the Visayas. The non-degree programs include regular short-term courses, onsite seminars internship training and practicum for graduating students. The "hands-on" short-term courses cover Prawn Hatchery and Nursery, Marine Finfish Hatchery, Brackishwater Pond Culture, Sanitation and Culture of Bivalves, Freshwater Aquaculture, Aquaculture Management, Aquaculture Engineering, and Aquaculture for Social Scientists. A profile of 637 1982-1986 training participants show 82.3% from Southeast Asia, 79% male and 57.5% from government sector. The paper discusses planning and implementation of training programs, funding support (Japanese Government, International Development Research Centre of Canada, FAO Network of Aquaculture Centres in Asia), and future trends.

Southeast Asia, a Subregion of the Asia-Pacific Region, is composed of countries of diverse socio-economic circumstances. Fisheries production, particularly that of the aquaculture sector, is relatively developed and is important to the economy of this area. Some 80 economic aquatic species are the subject of culture. Many of these species, which include fin fish, crustaceans, molluscs, and seaweeds, are produced in consequential quantities. Total production from the Subregion in 1983 amounted to about 880 000 mt which represented nine percent of total world aquaculture production in said year, and a 100% increase in the area within the decade (1975-1983). Unit production is comparatively low as it is usually done with the use of the extensive level of management developed after long years of experience by fish farmers. Higher rate of production in recent years is a trend especially for high value and exportable species like the penaeid shrimps. Aquaculture production tends to have accelerated growth while capture fisheries production tends to increase very gradually or levels off. Technical and non-technical constraints occur which hinder rapid progress of aquaculture in Southeast Asia. This will require the attention of research institutions and governments. However, bright prospects for future increase in production in this industry are developing in the area. Specific instances to support this forecast are discussed.