9/2002: Successful research helps make aquaculture more profitable

 MEDIA RELEASE

Successful research helps make aquaculture more profitable

A breakthrough in the breeding of live fish in aquaculture, made by Indonesian scientists working cooperatively with Australian scientists as part of an Australian Government development project, promises to boost the viability of local aquaculture in Indonesia.

Breeding groupers, such as barramundi cod, has proven almost impossible in the past, with survival rates for larvae averaging less than 5 per cent.  Through a project commissioned by the Australian Centre for International Agricultural Research, survival rates of up to 50 per cent have been achieved.  The techniques behind this success are now spreading to backyard hatcheries near the project site in Gondol.

The project aimed to develop techniques to improve live breeding of fish in aquaculture.  Up to now, most aquaculture of finfish has involved the capture and rearing of juvenile fish caught in the wild, rather than breeding in captivity.  The capture of juvenile fish, though profitable, quickly depletes wild fish stocks.

For smallholder fish farmers, getting mature fish to lay eggs has not been the problem.  However it has been almost impossible to keep the larvae alive until they reach the juvenile stage.  The main barrier, which the project scientists set out to overcome, has been rearing the tiny larvae, which depend on getting feed of the right size – small enough to swallow and nutritionally sufficient to support growth.

Working at Gondol’s Central Research Centre for Aquaculture, the project team found that food supplied to the larvae of barramundi cod and tiger grouper was too big to be swallowed, and nutritionally poor.  The inevitable result of using such feeds is almost total failure to rear fish.  Most died after 20 to 30 days of rearing, wasting the time and money invested.  This also deprived smallholders of the valuable income they could get from delivering healthy fish to the live fish markets of Asia.

The team of Indonesian and Australian scientists made a breakthrough when they identified a new food suitable for rearing fish larvae.  The fish larvae were first fed a super-small species of rotifer ( a small invertebrate species) which allowed them to consume enough food to grow through the early stages of development.  Once past this stage an artificial diet of nutritious particles, designed to simulate particles falling through the water in wild conditions was developed.

The survival rates have been between 30 per cent for tiger grouper and 50 per cent for barramundi cod.  Such has been the success of the rearing techniques developed that local smallholders around the Gondol research station have quickly adopted them.  For the first time local smallholders have been able to rear larvae through to market ready stage, and produce enough fish to make local enterprises viable.