Although the idea of eating raw fish is still off-putting to some people, the worldwide demand for the Japanese delicacy has been growing rapidly. An article in Wired indicates that some sloppiness in processing at least, and possibly deliberate deception, is happening in the market for the most coveted species of fish:
The article reports on a new research paper, published in the online journal of the Public Library of Science, in which researchers, from Columbia University and the American Museum of Natural History, obtained samples of tuna sushi from various vendors, and then used DNA “bar codes” to identify the species of each sample. This kind of identification is of considerable interest in conservation, since it would make enforcing bans against fishing for endangered species (such as the southern bluefin tuna, Thunnus maccoyii) more effective.
Unfortunately, the researchers found that you can’t necessarily tell the sushi from the menu:
“A piece of tuna sushi has the potential to be an endangered species, a fraud or a health hazard,” wrote the authors. “All three of these cases were uncovered in this study.”
The sushi as bought was labeled from the very general (“tuna”) to very specific (“White tuna – albacore”). Some of the samples turned out to be from the endangered southern bluefin; five of the samples advertised as “white tuna” were not in fact albacore, but a totally different fish called escolar (Lepidocybium flavorunneum), which is banned from sale in Italy and Japan because of health concerns — eating it can cause moderate to severe intestinal distress.
Hopefully, the further development of these techniques will help protect endangered species, and will also make having a sushi lunch a little less potentially troubling.