As the importance of engineering to aquaculture becomes more apparent it is also realized that the physical properties of a pond have a strong influence on its productivity. This article reports the plans and programmes of the SEAFDEC Leganes station on pond design with reference to site location, ponds and supportive facilities, their general layout, design and specifications and construction. Shrimp and milkfish culture is mentioned. Problems are considered and finally recommendations are made.

With the advent of new research and studies into aquaculture practices there is a need to improve the size and shape of brackishwater ponds in the Philippines and to make their management more efficient. This article discusses the survey and layout of the project and the engineering aspects of pond management. Milkfish pond management is also considered.

The sugpo, Penaeus monodon, is a very important prawn species in Southeast Asia. It is extremely euryhaline and fast growing. Interest in the farming of this prawn species is very high. Unfortunately, the supply of natural fry is not sufficient. It is, therefore, necessary to develop the technology of breeding them in captivity and producing sufficient seed material. The Southeast Asian Fisheries Development Center, Aquaculture Department in Tigbauan, Iloilo, Philippines, operates a hatchery to produce fry for experimental rearing in brackish water ponds and for various laboratory studies.

T. mossambica were grown to marketable size in floating cages in Laguna de Bay at a stocking density of 75/m². Those given supplemental feed 1 (rice bran:ipil-ipil:fish meal, 60:20:20) showed significantly faster growth than those fed with supplemental feed 2 (chopped snails:rice bran, 30:70). Controls, without supplemental feeding, showed slower growth rates as compared to the supplement-fed lots. A more efficient feed conversion ratio was obtained for feed 1 (4:1) as compared to feed 2 (6:1). Laboratory experiments in aquaria showed the feasibility of improving the growth of tilapia with ipil-ipil (Leucaena leucocephala) leaf meal alone. Varying levels of ipil-ipil, given at 3, 6, and 9% of the body weight, increased the body weight to 0.75 g, 1.68 g, and 2.94 g, respectively. Moreover, the crude protein content of tilapia increased proportionately with increasing levels of ipil-ipil leaf meal. The significance of the above results in the light of establishing a tilapia lake farming industry and its effect on the improved nutrition of the people were discussed.

The objective of the inoculation described in this paper was to test the feasibility of culturing Artemia in man-made earthen salterns and of producing adults and cysts for use in aquaculture projects in the Philippines. San Francisco Bay (California, USA) Artemia were inoculated in two concrete tanks and in four earthen ponds which are part of a small local salt factory. It was found that Artemia can be grown (with continuous production of nauplii and cysts) year-round in covered concrete tanks and in open concrete tanks and earthen ponds during the dry season (February to June). Lethal effects of too high water temperatures (>35°C) to the cultures were anticipated by the use of green coconut fronds placed on the water surface alongside the walls of the tanks and the earthen dikes. Rice bran enriched with vitamins and traces of minerals appeared to be a good food for Artemia cultured in aerated concrete tanks; in the earthen salt ponds the brine shrimp grew well on the natural food present. Over a 3 month production period, 26 kg dry weight cysts and 150 kg live weight adults have been harvested from a total surface of 1.7 ha of salt ponds and brine tanks.

A review is presented of some practical methods that may be applied by fish farmers in producing food organisms for fish and prawn hatcheries. Organisms involved in the discussion include Moina, chironomid larvae, mosquito (Culex) larvae and earthworm (Lunbricus).

The use of yeast as feed in aquaculture is discussed. It has been successfully used as feed for Penaeus japonicus larvae, for Brachionus plicatilis mass culture, and for the improvement of nutritional quality of Tigriopus japonicus. It has been found most effective as supplemental food when enough phytoplankton cannot be supplied.

It is a common belief that the zoea of Penaeus monodon are completely filter feeders. Thus, diatoms like chaetoceros and phytoflagellates are maintained at high feeding densities as much as 80 000 cells/ml in hatchery tanks during the zoeal states of the P.monodon. This feeding scheme often results in the reddening of the larvae followed by weakening, loss of appetite and eventual mass mortality. It was found out recently that zoea larvae are not completely filter feeders. It was observed as early as Zoae 1, the mouth parts of the larvae are already functional and can eat food particles as big as Artimeia and Brachionus. Based on this observation, a new feeding scheme was developed. Boiled egg yolk is fed to the larvae at 15-22 particles (as big as Brachionus) per ml from Zoea 2 to Mysis 3 stages. Tetraselmis is given from Zoea 1 to Mysis 3 stages at a low density level of 5 000 cells/ml. Artemia is also fed at 10-15 individuals/ml from Mysis 1 to Postlarvae 5. If Tetraselmis is not available, bread yeast is given from Zoea 1 to 3 at 0.1-03 g/ton as supplementery feed. With this new feeding scheme, the hatchery producers have been greatly simplified considering that the most difficult and tedious part in larval rearing is the maintenance of algal food especially diatoms. This feeding scheme was tested in a private hatchery in Bataan, Aklan province by the SEAFDEC Aquaculture Department from July to October 1981. All 44 runs were successful, yielding survival rates ranging from 22 to 75 percent and an average rate of 52.9 percent. The hatchery system was further simplified when experiments at the Bataan Substation of the SEAFDEC AQD revealed that as high as 60 percent survival can be attained with minimal aeration. Instead of centralized aeration system using compressors or blowers, portable aquarium-type aerators (5-watt) could be use thus minimizing energy consumption. Based on these developments, a new model for a small-scale hatchery system is proposed. based

Research on larval rearing of Macrobrachium is reviewed. The future of prawn culture is discussed.

This paper discusses the handling and rearing of hatchery-produced Penaeus post larvae. The survival and growth of hatchery produced fry and wild caught fry are discussed.