Is Your Sushi Killing an Entire Species?

If you're eating tuna sushi, chances are good that it's been made with bluefin tuna, one of the most threatened species of fish in the world. Using DNA barcoding, a new study found that many sushi menus do not label items made with bluefin tuna, despite a growing public desire to avoid eating bluefin, and despite their higher cost. And of the menus that did denote which species was being served, several were wrong—meaning that you might try to order safely and conscientiously, but it's not unlikely that you are, even if by accident, being lied to.

Of the 31 restaurants sampled in New York and Colorado, 19 "erroneously described or failed to identify the sushi they sold," the study found. Not bothering to identify the fish when it could well be a threatened species is bad enough—but worse still, the DNA tests found that 14 of the sushi samples were bluefin tuna, without being indicated as such on the menus.

You can try to make informed choices by asking your waiter what kind of tuna is served, but it's semi-likely you'll get a wrong answer—not out of deceit, the study points out, so much as because tuna is such a broad category and a lack of education plays a large role.

Sushi testing... in Colorado?

Why was the study conducted in NYC and Colorado? Not exactly a state known for its seafood. But it was in part, said researcher Jacob Lowenstein, because it was important to show this issue is not confined to NYC. Indeed, said the study, "The only way for consumers to positively avoid consuming bluefin is abstinence from tuna sushi if the verbal confirmations we found is representative."

A species in peril

All three types of bluefin tuna—the northern, southern, and Pacific—are prized catch for fishermen because of the high prices they fetch, and despite their plummeting populations, fishing is still allowed. A ban was considered just last month, but denied in favor of reduced quotas—which critics say will only invite illegal fishing.

Atlantic bluefin stocks are said to have fallen to 25 percent of their pre-commercial fishing levels, with overfishing in just the last 10 years causing 60 percent of that decline. Scientific American reports, "scientists warn that continuing to fish the bluefin at current levels will push the population to 94 percent below the size it was before commercial exploitation began, effectively collapsing the fishery and putting some populations at risk of extinction."

Here's hoping the Convention on International Trade in Endangered Species will act a little more courageously when it meets in March than the International Commission for the Conservation of Atlantic Tunas did last month when it decided to do, well, essentially nothing.

In the meantime, a smart move for the planet and for poor tuna everywhere is to not order it at dinner. (Or lunch.)

Ever had veggie sushi rolls? They're mm-mm-good.