The Future Of Sushi: Farms?

by Bradford Plumer | August 5, 2009

Is the end of sushi upon us? It may well be. Bluefin tuna stocks all over the world are on the verge of collapse, thanks to overfishing. The World Wildlife Federation has estimated that Northern bluefin could get wiped out within three years, while the Southern bluefin is critically endangered. If those two species vanish, fisherman will set their sights on the only-slightly-less-beleaguered Pacific bluefin, which, presumably, won't appreciate the newfound attention.

So far, conservation efforts have proved inept—last year, the nations that make up the International Commission for the Conservation of Atlantic Tunas (ICCAT) set an annual quota of 22,500 tons worth of tuna per year. Not only is that far above the amount scientists recommend (think 7,500-15,000 tons per year, max), but fisherman are basically ignoring the ICCAT agreement—last year some 60,000 tons of Northern bluefin were hauled ashore. The tuna industry is just too lucrative—and the fishing industry doesn't seem to care if it could evaporate within a decade.

So that leaves a few options. Some environmental groups are talking about trying to constrain sushi demand worldwide by essentially waging a public campaign to make eating bluefin tuna as socially toxic as, say, buying ivory products. Who knows how that will go? The one other possibility, as Brandon Keim in Wired reports, is to try to farm bluefin. It's not as easy as farming, say, salmon (bluefin tuna travel thousands of miles across the ocean and don't tend to spawn in captivity), but scientists may be on the verge of a breakthrough:

It’s now a technology question, not a biology question,” said fish physiologist Christopher Bridges of Heinrich Heine University in Dusseldorf. “How long will this take in terms of development and experimentation? That’s the bottleneck. And I have no doubt this bottleneck will be solved.”

Bridges is one of dozens of European scientists involved with the Allotuna and the Selfdott Northern bluefin-breeding programs. They’ve developed hormone treatments that coax tuna into spawning while they’re held in coastal pens. That seemingly simple feat hadn’t yet been done in the Northern bluefin, whose reproductive habits are in many ways still a mystery.

Of course, there's a catch:

Even if farmed bluefin flourish, feeding them could be a problem. Though the Japanese researchers are trying to develop a grain-based diet, it’s possible — perhaps probable — that bluefin will insist on natural fare. “Presumably that will require vast amounts of bait fish to feed them,” said Richard Ellis, author of Tuna: A Love Story. “From the perspective of catching fish to feed fish, this is a step backwards.”

Fair enough. The other thing to note here is that, even if researchers do figure out how to breed tuna in captivity and ease the pressure on wild stocks, fish farms cause huge ecological problems of their own. You want to see gross, check out the recent news on Chile's massive salmon farms, where fish are bred in cramped pens, smother the coastal bed in feces and antibiotics, and are now ravaged with disease. But if there's no way to persuade the fishing industry (and consumers) to opt for sustainable catch limits—the one proven method for rebuilding fish stocks—then farming may well be the only future for the bluefin tuna.

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