In this issue:

Cage aquaculture of tilapia in Lake Taal, Philippines. Development and adoption of BMPs by farmer groups. Lotus - an aquatic plant of versatile qualities. Integrated aquaculture-agriculture systems in Bangladesh: Potential for sustainable livelihoods and nutrititional security of the rural poor. Spreadsheet model of the market chain for the live reef food fish trade. Regional Grouper Hatchery Production Training Course. Replacing marine fish oil in aquafeeds with tropical palm oil products. NACA Newsletter.

In this issue:

Peter Edwards writes on rural aquaculture: Recent developments in Chinese inland aquaculture. Reducing feed costs in aquaculture: Is the use of mixed feeding schedules the answer for semi-intensive practices? Seed production technology of ornamental gouramis Colisa fasciata and C. lalia under captive conditions. Marine finfish market information and aquaculture development trends in selected locations in Indonesia and Malaysia. Market analysis of the live reef food fish trade.

This manual provides guidelines for attaining better practices in culture-based fisheries, an emerging practice in rural areas in the Asian region. It deals with the principles of culture-based fishery practices, primarily based on relatively long-term experiences in Sri Lanka and Vietnam. It deals with the gross factors that are applicable to improving fish yields and therefore revenue; and sustaining culture based fisheries as a development activity in the long-term.

These guidelines provide advice on producing fish seed in small-scale hatcheries. This publication is also available in Oriya.

‘Spawn’ is the name for the young fish about three days old that are available from hatcheries. Sometimes these young fish are also called hatchlings. The spawn of catla, rohu and mrigal is about 6-8 mm long. At this stage, the ‘yolk sac’ is absorbed, the mouth opened and the fins fully developed. Spawn are reared intensively, first to the ‘fry’ size and then to the ‘fingerling’ size. All the three stages are marketed and collectively called ‘seed’.

The “fast fingerling system” can produce advanced fingerlings about two months earlier than they are normally available from fish farms.  The farmer uses just one pond for continuous growing until fingerling size is reached, and fewer fish are stocked. A farmer with a small, seasonal pond can produce fingerlings in one month. These can then be sold for a high price because everyone wants fingerlings as early as possible.

The fingerling rearing pond, like the nursery pond, should be free from weeds and predators. Submerged weeds and predators are killed by mahua oilcake, which then acts as a good fertiliser. If there are no weeds, to kill predators and competitors quickly you can just add 100 kg of urea followed 24 hours later by 200 kg of fresh bleaching powder for a 1-ha area of a 1-m deep pond.

In watersheds, medium irrigation projects can be useful for aquaculture even though these water bodies are many times larger than ponds, and are basically built for irrigation or water storage. However, the full potential of these water bodies is not yet realised. Net pens or cages can be used to rear fingerlings in such environments.

It is best to stock advanced fingerlings in large ponds, tanks, and in both small and large reservoirs, since they can better escape predators and competitors. Seasonal ponds, often 0.10-0.15 ha and 1.5-1.8 m deep can be used as rearing ponds for raising advanced fingerlings. Low water levels at the end of the season will make netting and harvesting easy.

Everyone wants advanced fingerlings as early after the rains as possible. They fetch a good price and make marketable fish production possible in seasonal ponds. One way to produce early season advanced fingerlings is to grow them in perennial ponds and store them at high density with minimal feeding for the coming year. Whe such "stunted" fingerlings are stocked into ponds with good feed they grow fast and can be marketed in about 6-8 months.