But some scientists are betting on bluefin aquaculture to save the species and lessen pressure on wild stocks. The Australian company, CleanSeas, has been been working closely with scientists from Japan's Kinki University breeding programs with two different strains of tuna: Northern Pacific genetic strain for Kinki University, and CleanSeas' from the Southern Pacific genetic strain. Both programs are in their infancy, which means fish is currently trickling into U.S. restaurants.
Unlike tuna ranching, where juveniles are harvested from the wild and fattened in open pens, Kindai tuna are farm-raised from eggs hatched in a laboratory, rather than being taken from wild stocks -- a process so revolutionary that it ranked second on Time Magazine's 50 Best Inventions of 2009. Chef Chris Chung, at the newly opened AKA Bistro near Boston, embraces the farmed bluefin, and says it is very close to wild bluefin in flavor. It's the single most expensive item on his sashimi menu, and is listed as "Kindai Toro (special featured low mercury tuna belly)" for $23. Less mercury, he says, because the tuna is taken from the water at a younger age. Many of Chung's customers are very aware of Kindai.
"They ask me, 'When did you start getting this laboratory tuna?'" says Chung.
But some say the farming of bluefin is akin to farming tigers.
"You are farming a very inefficient top predator," says Pete Bridson, aquaculture research manager for Seafood Watch.
When you consider the economic realities, Kindai's claims of lessening pressure on wild stocks don't add up. Fishermen will still go after wild bluefin which can be sold for upwards of $100,000 a fish, Bridson says. And then there's the issue of the fish-in/fish-out ratio. While the exact numbers CleanSeas has reached remain unclear, overall, farming large predators like bluefin is considered unsustainable.
Martin Reed, founder of I Love Blue Sea, a sustainable fish wholesaler and retailer based in San Francisco, agrees that Kindai is not a good alternative.
"I absolutely would not carry it. Kindai does a good job of marketing. It's a step in the right direction from eating wild bluefin, which is the worst thing you could to, but it's not a very far step," he says.