What an extraordinary fish. Bluefin tuna have the potential to grow huge, the largest of all bony fish – the record for one caught is 1496 lbs, and 1000 lbs (450 kg) used to be common. Like all tuna, they thermoregulate, staying relatively warm in cold water, and that lets them chase down colder, slower fish. A magnificent predator.
Their story as human food is well known, for they are by far the most valuable of fish, provided they are frozen quickly and properly as soon as they are caught, decapitated and gutted, and sent to the famous fish markets of Japan. The Japanese pay dearly for their bluefin sashimi (raw slices, dipped in a delicate sauce) and for their bluefin sushi. Communities around the world depend on bluefin fishing, paid for by the Japanese market.
As the whole world also knows, stocks of bluefin tuna are in serious decline, and collapse looms ahead. In the Mediterranean, the average size of a captured bluefin in 2001 was 124 kg; now it is close to 60 kg. That’s not just small – that’s too small to have had a chance to reproduce. Reproductive failure is the usual cause of collapse.
As a result, bluefin ranching has become widespread, for instance in the Mediterranean, where the small tuna are fed massive amounts of bait fish to grow and fatten them to then harvest, freeze, and send off to Japan. Sounds more sustainable? It isn’t. Each tuna eats many times its own weight in bait fish to grow large enough to become sushi.
This past week, bluefin tuna have gathered headlines once again. Despite efforts to ban the global bluefin hunt, the 175 nation Convention on International Trade in Endangered Species (known as CITES) easily voted down the ban. Japan lobbied furiously, and all the countries that need the income provided by their tuna fishing added their support. The hunting and the ranching will continue, at least for another two and a half years when CITES meets next. That is coincidentally about as long the World Wildlife Fund considers it will take for the collapse to occur.
Japan is very defensive. They deny that bluefin collapse is imminent, and accuse the rest of us of attacking their culture. If they had lost the UN vote, they intended to ignore it anyway.
There is, however, a solution. The problem is not eating sushi or sashimi, it is eating endangered species such as bluefin. There are plenty of alternatives. No doubt raw bluefin tastes especially fine to the experienced palate, but surely a secure culture can persist on the backs of sustainable species instead.
And we can help. Though 80% of the bluefin catch goes to Japan, the rest mostly goes to Japanese restaurants elsewhere in the world. Perhaps you also love the taste of sushi and sashimi. If so, the best place to start is to follow the Monterrey Bay Sushi Guide. And where you notice bluefin on the menu, challenge it!
Clearly we can’t wait for the UN to mandate appropriate conservation measures. As always, it is up to us.