Fish species fraud is rampant in the restaurant industry.

You're probably not eating the fish you think you're eating

I have heard rumblings of this problem for years, mostly from less-than-reliable sources. Former employees who might have an axe to grind, celebrity chefs who could just be trying to smear their competition, industry insiders trying to make themselves sound more "insider-y than thou," and so forth. But this recent study by a Stanford marine biologist clinches it: fish is being deliberately mislabeled by restaurants to a colossal extent.

Steve Palumbi has been churning through DNA analysis and samples, and he has come up with a lot of interesting - and somewhat horrifying - conclusions. Tuna is usually labeled correctly, but he has found that salmon on the menu is almost certainly the similar-in-taste but far cheaper, steelhead trout.

These silent, fraudulent substitutions are occurring all up and down the line, from upscale restaurants to small neighborhood grocery stores. As a general rule, the more expensive the seafood, the more likely it is to be fake. (There's no point bothering to substitute for a cheap piece of fish.) Studies have found that up to 40 percent of the fish served in restaurants in New York, Los Angeles and Boston had been deliberately mislabeled.

Palumbi says that crab, clams and shrimp are usually what they purport to be. But red snapper is usually a cheaper species of rockfish. And worse, fish labeled as "Sustainably Caught" often isn't. However, Palumbi has found that virtually all of the fish sold at his local Whole Foods market is correctly labeled. (All of it, strangely enough, except the sardines.) The cynic in me says it's because Whole Foods customers are willing to pay the correct, higher price for the right seafood.

I get it, I really do. It's incredibly different to make it these days as a restaurant, and being able to subtract a dollar or two from your marginal cost on a dish could be the make-or-break difference in a restaurant's finances. But that doesn't make it right, and this practice needs to end.

Image courtesy of Flickr/Frank Swift