An investigation that has taken place in the US could result in the printed labels on fish products being double-checked in the UK.
Consumer Reports carried out research on 190 pieces of seafood bought in New York, New Jersey and Connecticut stores or restaurants by testing samples of DNA against standardised references.
It was discovered that more than a fifth of the samples were mislabelled, incorrectly described or misidentified by employees.
Only four out of the 14 types of fish were always correctly identified, with some products incorrectly passed off as halibut, lemon sole and yellowfin tuna.
Consumer Reports' Kim Kleman pointed out that this could be making it hard for consumers, who are advised to check peelable labels on fish for sustainable supplies and low levels of contaminants.
"Whether deliberate or not, substitution hurts consumers three ways: in their wallet ... in their health ... and in their conscience," she added.
In July, Emily Howgate from Good Catch suggested that consumers should pressure retailers into providing detailed printed labels for fish so the species and location caught is immediately visible.
Denny Bros Ltd, 04 November 2011
