That "sustainable" Chilean sea bass you bought in the grocery store might not actually be so sustainable—and might even be a different kind of fish entirely. That's according to researchers who tested DNA samples of fish labeled as having been harvested from a fishery with sustainable fishing practices.
The researchers, from Clemson University, isolated DNA samples from Chilean sea bass, an over-fished species. All the samples carried labels from the Marine Stewardship Council, indicating that they were harvested from the only recognized sustainable Chilean sea bass fishery in the world, a region surrounding the sub-Antarctic island of South Georgia and a nearby underwater plateau. But about 15 percent of the samples were genetically distinct from fish collected previously from the certified fishery. One sample carried a genetic variant that has only been found in the southern Indian Ocean.
Because fish passes through many hands after it is caught, and before it reaches the market, it is unclear when the fish was mislabeled.
"The simplest explanation for this result is that other species, plus Chilean sea bass, from other, uncertified fisheries are being added to the supply chain for MSC-certified Chilean sea bass," said Peter Marko of Clemson University. "The results are not exactly shocking," said Marko, given the widespread mislabeling in the seafood industry because of the potential profits to be made.
These most recent findings add to earlier reports that labeling fraud is common in commercial seafood. Back in May, the non-profit group Oceana came out with a report based on DNA tests that confirmed disturbingly wide seafood fraud. Oceana’s finding came on the heels of a report by the U.S. Government Accountability Office recommending improvements to government oversight of imported fish.
DNA analysis shows Eco-labeled seafood is not always what it seems [Current Biology]