from Sunday's Boston Globe:

The sliver of raw fish sold as white tuna at Skipjacks in Foxborough was actually escolar, an oily, cheaper species banned in Japan because it can make people sick. The Alaskan butterfish at celebrity chef Ming Tsais Blue Ginger in Wellesley was really sablefish, traditionally a staple at Jewish delicatessens, not upscale dining establishments.At Chau Chow Seafood Restaurant in Dorchester, the $23 flounder fillet turned out to be a Vietnamese catfish known as swai - nutritionally inferior and often priced under $4 a pound.Those were among the findings of a five-month Globe investigation into the mislabeling of fish. It showed that Massachusetts consumers routinely and unwittingly overpay for less desirable, sometimes undesirable, species - or buy seafood that is simply not what it is advertised to be. In many cases, the fish was caught thousands of miles away and frozen, not hauled in by local fishermen, as the menu claimed. It may be perfectly palatable - just not what the customer ordered. But sometimes mislabeled seafood can cause allergic reactions, violate dietary restrictions, or contain chemicals banned in the United States.The Globe collected fish from 134 restaurants, grocery stores, and seafood markets from Leominster to Provincetown, and hired a laboratory in Canada to conduct DNA testing on the samples. Analyses by the DNA lab and other scientists showed that 87 of 183 were sold with the wrong species name - 48 percent.

The rest of the twinned tail is here.Watch your sushi:from the follow-up report in today's Globe:

In the early-morning hours, workers at a ... warehouse in Boston load boxes of frozen escolar into vans for delivery to area sushi restaurants.By the time the fish appears on diners plates, it has undergone a Cinderella-like transformation: the escolar, which can cause digestion problems, is presented as white tuna or albacore - more palatable and pricier fish.