Japanese scientists may have found a way to save wild bluefin tuna from extinction by successfully breeding and raising the fish in captivity for the first time.
Scientists from Kinki University in Wakayama have been working on the technology for 30 years.
“The first challenge was to increase survival rates from harvested eggs to hatchlings, and we got it to 5 per cent,” the university’s Professor Yoshifumi Sawada said.
“The bluefin hatchlings ate each other, so we then had to introduce other types of hatchling species for them to eat.”
The scientists also faced the difficulty of replicating the best conditions for bluefin, which are notoriously hard to breed in captivity due to their sensitivity to water temperature, currents and noise.
Swimming at up to 80 kilometres per hour and weighing up to 350 kilograms, half of the bluefins die in collisions despite being kept in huge circular pens.
After four years in the pens the fish are killed with an electric shock before being processed to help meet Japan’s appetite for sushi and sashimi. Each fish can serve about 200 people.
Scientists are now in the process of mapping the bluefin’s entire DNA from blood samples, in a bid to isolate the best genes for disease resistance and high growth.
Tokihiko Okada, general manager of Kinki Fisheries, checks on the development of the 4,000 bluefin tuna every day.
“Our mission is to supply about half of the Japanese domestic market,” Mr Okada said.
“We’ll need about 300,000 but we’ll get there and reduce the pressure on tuna in the wild.”
Restaurant profits from tuna go back to science
As well as mastering the technology to ensure sustainable bluefin supplies, the scientists at Kinki University have developed a business model in which they own the restaurants the tuna are sent to.
The profits they make at the restaurants then fund future research and development for bluefin tuna.
The notion that farmed tuna has less taste and flavour than wild tuna has dissolved, as evidenced by the number of customers who line up outside the Kinki University restaurant from the early morning to secure a seat.
Farmed tuna also has the added health benefit of containing less mercury than wild fish.
As well as the satisfaction of using sustainable produce, Kinki restaurant’s head chef Tauya Sugimura has significant control over the taste of the bluefin.
“If we want to change the taste we just ring the farms at Wakayama and ask them to reduce or increase the fat content and it happens,” Mr Sugimura said.
The scientists at Kinki University are now selling their unique technology and business model to the rest of the world with America and Malaysia taking up the franchise.
In 2009 Australian tuna baron Hagen Stehr warned that aquaculture was the only viable way of meeting a growing demand for seafood.
“That is the only way we will be eating seafood into the years ahead. Anyone who invests in sustainable aquaculture practices will make it big time in the future,” Mr Stehr said.
In 2008 Mr Stehr’s aquaculture business Clean Seas Tuna became the first company in the world to create an artificial breeding program for southern bluefin, but struggled to produce viable adult fish and has since refocused its efforts on breeding kingfish.
sumber: http://www.abc.net.au/news/2015-04-08/bluefin-tuna-farming-japan/6373310
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