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.