DNA barcoding reveals mislabeled cod and haddock in Dublin

Apr 22, 2010

Ecological scientists in Ireland recently used DNA barcoding to identify species of fish labeled as either "cod" or "haddock" in fish and chip shops, fresh fish counters and supermarkets in 10 postal districts in Dublin. They found that 39 out of 156 (25%) randomly sampled "cod" and "haddock" were genetically entirely different species and, therefore, mislabeled under European Union (EU) regulations.

In addition, as Dana Miller and Stefano Mariani from University College Dublin report in today's Frontiers in Ecology and the Environment (e-View), 28 out of 34 (82.4%) smoked samples were incorrectly labeled, and 26 out of 28 (92.9%) samples labeled as "smoked cod" were completely different species.

"In light of recent findings from North American scientists using the same approach, it seems mislabeling seafood is pervasive on a global scale," said Miller. "This, coupled with the enormous rise in seafood demand, raises alarm. There is an increasing need for effective and sustainable seafood industry management and especially for transparency within the seafood industry itself on an international level."

Last April, researchers Ron Burton and Phil Hastings from the University of California, San Diego used to identify fish served in New York restaurants; they found that 25% of the fish were mislabeled.

"Consumers should be able to go to a shop and know they are eating what they paid for, especially when the product is purchased within the EU, where numerous policies relating to labeling and tracing are already in place," said Mariani. The authors argue that these findings suggest mislabeling could contribute to overfishing—that is, mislabeling cod in Ireland could be creating a false perception of market availability.

"There are many problems associated with mislabeling fish, like in the case of mislabeling the depleted to enhance perceptions of availability in the U.S.," continued Miller. "Consumers may think that if 'cod' keeps showing up in markets and restaurants across Ireland, the stocks must be healthy."

The fish samples the researchers tested included smoked, fried, battered, fresh and frozen cod and haddock. Approximately 25% of these samples turned out to be cod labeled as haddock or vice versa, or a completely different species of fish altogether, such as pollack, whiting or saithe, mislabeled as cod or haddock or even Pacific cod being labeled as Atlantic cod.

To identify the correct , the scientists extracted tissue from each sample and entered the gene sequences into the Barcode of Life Data Systems online at www.barcodinglife.org; the researchers also cross-referenced the sequence with other databases. The study includes a complete list of all analyzed fish, as they were labeled and identified.

"With the rapid advances in bioinformatics, the traceability of fish stocks will be more affordable and available," said Mariani. "This will hopefully make enforcing the proper labeling of fish easier and will subsequently encourage transparency in the fishing industry. With a restored trust in retailers and policymakers, the seafood industry can be turned into a sustainable operation on a global scale."

Explore further: PacifiCorp Energy pleads guilty in bird deaths (Update)

Provided by Ecological Society of America

not rated yet
add to favorites email to friend print save as pdf

Related Stories

North Sea cod and herring under threat

Jun 26, 2006

European scientists say cod and herring populations in the North Sea are not reproducing enough, jeopardizing the Norwegian fishing industry.

British cod stocks rebounding

Oct 22, 2007

Researchers say cod stocks around Britain have rebounded enough to permit small catches in the North Sea, The Times of London reported Saturday.

EU sets fish quotas for 2007

Dec 22, 2006

The European Union fisheries ministers have set the 2007 limits for fish catches in European waters.

Warming drives off Cape Cod's namesake, other fish

Nov 12, 2009

(AP) -- Fishermen have known for years that they've had to steam farther and farther from shore to find the cod, haddock and winter flounder that typically fill dinner plates in New England.

Recommended for you

Study finds tropical fish moving into temperate waters

Dec 19, 2014

Tropical herbivorous fish are beginning to expand their range into temperate waters – likely as a result of climate change – and a new international study documents the dramatic impact of the intrusion ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

baudrunner
not rated yet Apr 22, 2010
Mislabelling Cod for Haddock and Haddock for Cod? That's not evidence of fraud, but evidence of stupidity!

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.