Skretting develops feed concept for captive tuna

Skretting develops feed concept for captive tuna

Skretting ARC and Skretting have developed a feed concept for bluefin tuna in captivity.

Companies and research teams worldwide are approaching the successful breeding and rearing of bluefin tuna in captivity.

Skretting Australia has been involved in research on bluefin tuna since 1997. Over the past year, Australian tuna farmers have been able to conduct commercial farming of this lucrative species using the company''s feed.

Farmers have had a difficult time with the task because bluefin tuna apparently have what the firm calls ''''a discerning palate.''''

''''The main challenge was to develop a feed with a texture and size that the bluefin tuna wanted to eat, at the same time as containing sufficient and the correct nutrients,'''' said Karl Sveinsvoll, a researcher in Skretting ARC. ''''This problem was solved by using the feed block concept, Aurora Gel, which was patented in 2003.''''

According to Sveinsvoll, ARC and Skretting are also now testing a new generation of feed blocks, which they have named AquaSoft Tuna.

''''There are significant advantages of feeding formulated feed to bluefin tuna, as the alternative has usually been to feed them ''trash fish,'' such as herring and mackerel, with a feed conversion ratio of up to 20. Formulated feed contributes toward greater sustainability, traceability, less risk of transmitting disease and better control of the nutritional profile of the fish,'''' he added.

Skretting is also currently testing the bluefin tuna feed in Japan, Spain and Turkey. The results in Japan have been positive thus far.

The trials ran in Spain and Turkey, however, were not successful until recently, when the team saw a breakthrough in Spain with the new feed.

Although Skretting has produced a feed that the bluefin tuna has agreed to eat, some pressing problems remain to be solved before commercial farming of the species is possible.

Bluefin tuna farming is currently based on catching wild fish and feeding them until they reach harvesting weight.

''''The challenge is to get the fish to reproduce in captivity and to get the fry to survive into adulthood,'''' Sveinsvoll explained.

The challenge of ''''closing the life cycle'''' is the topic of SELFDOTT (SELF-sustained aquaculture and DOmestication of Thunnus Thynnus), a European Union (EU) funded research project, in which Skretting ARC, among others, is taking part.