Eco-labelled fish not always sustainably sourced

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A recent study has revealed that not all fish labelled as Marine Stewardship Council (MSC)-certified are from a sustainable source.

The promotion of sustainably sourced seafood is becoming ever more prominent with the on-going decline and collapse of many of the world’s fisheries. However, a recent study reported in Current Biology reveals that by using DNA testing, not all fish that received MSC label were indeed from a sustainable source.  

Peter Marko of Clemson University explains: "We found that, for fish purchased in US groceries, not all those labelled as MSC-certified Chilean sea bass are actually MSC-certified Chilean sea bass."

An ecolabel awarded by the MSC should be certification for sustainable practice. For Chilean sea bass the label should be an indication that the fish in question were fished from around the sub-Antarctic island of South Georgia and a nearby plateau known as Shag Rocks. This area is the only Chilean sea bass fishery that the MSC recognises as being sustainable.

Adding insult to injury, some of the fish purchased were a different species altogether, while 15% of the Chilean sea bass were genetically distinct from those caught from the certified fishery.

One sample showed a genetic variance only found on the other side of the world, with others traced to South American waters and some had never been sampled before in genetic surveys.

"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," Marko said.

Although unexpected, "the results are not exactly shocking."

It’s not clear where responsibility lays as fish pass through many hands between capture and purchase, thus Marko’s advice for consumers is to stop eating Chilean sea bass, "at a grocery or on a plate in a restaurant, Chilean sea bass from South Georgia looks the same as Chilean sea bass from other parts of the world."

"There is no question that organisations like the Marine Stewardship Council are trying their best to guide consumers to sustainably harvested seafood, but it is currently difficult to guarantee the geographic origins of fish," Marko said, adding that the MSC has been working on ways to confirm fishes' origins, and the new study may serve as a model for how to go about that.

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