Scientists at George Washington University used a sophisticated genetic measurement technique to study seafood prepared at various restaurants in the nation's capital.
According to their findings, 33% of the seafood collected from six Washington, D.C., restaurants was mislabeled. What was on the plate wasn't the species listed on the menu.
Even though the researchers say the substitute species were closely related or considered an acceptable alternative, it reflects a trend found previously in other cities. Restaurants, knowingly or unknowingly, are substituting fish, and in some cases, the substitute is not that closely related to the fish on the menu.
Keith Crandall, PhD, director of the Computational Biology Institute at George Washington and leader of the new study, says there have been cases where diners in other cities ordered an expensive tuna but ended up with a cheaper fish, or even one on the endangered species list.
Crandall said that led him to undertake his study of DC restaurants. The researchers used DNA barcoding on a dozen seafood samples they obtained by eating at six restaurants. While there were some discrepancies, Crandall says they weren't egregious.
“Diners who ordered tuna got tuna, although maybe a slightly different type of tuna,” Crandall said. “We didn’t see the kind of outright seafood fraud that has been reported in other cities.”
Last September, the environmental group Oceana issued a report charging that 20% of seafood produced in 55 countries was mislabeled. In 54 of the countries, Oceana said it found mislabeling in every link of the supply chain -- retail, wholesale, distribution, import/export, packaging/processing, and landing.
If that were the case, it might be difficult for restaurant operators to know that the fish they were serving was not exactly what was on the menu.
Opportunities for fraud
“The path seafood travels from the fishing boat or farm to our dinner plates is long, complex and non-transparent, rife with opportunities for fraud and mislabeling,” Oceana senior campaign director Beth Lowell said at the time the report was released. “American consumers deserve to know more about their seafood, including what kind of fish it is, how and where it was caught or farmed, and they should be able to trust the information is accurate. The fight against seafood fraud must include all seafood and extend from boat to plate.”
Crandall says his study found no cases of fraud at D.C. restaurants. Of the 12 samples tested, the Chilean sea bass, two tuna and one rock shrimp had been mislabeled.
The team identified only one sample that was a concern -- one of the tuna was actually thunnus obesus, a species of tuna that is listed as “vulnerable” by international environmental authorities.