You're looking at a salmon on a fishmonger's slab. How can you tell whether it is a wild salmon or a farmed fish?

Until recently the answer was – ‘almost impossible’ - until, of course, you eat it and the superior quality of the wild salmon becomes apparent.

Now, thanks to pioneering research at Exeter University, it is possible to distinguish between wild and farmed fish by examining their DNA. This important scientific breakthrough will make it easier for the Environment Agency to detect a wild salmon being dishonestly ‘passed off’ as a farmed fish.

Anyone catching a salmon at sea while fishing for other species must return it to the water unharmed. Failure to do so is an offence under the Salmon and Freshwater Fisheries Act. It is also an offence to sell a rod caught wild salmon. Fishmongers and restaurants should only purchase salmon caught by licensed netsmen. Each wild fish must be tagged so its origin can be traced and fish must not be caught outside the official salmon netting season.

Environment Agency fisheries enforcement officers believe wild salmon are being caught by fishermen targeting species such as bass. In effect, the salmon are a ‘by-catch.’ Instead of returning them to the sea, some unscrupulous people are keeping these salmon and selling them on.

The sale of wild salmon and sea trout is covered by stringent regulations.Wild fish fetch premium prices and anyone advertising a salmon as a wild fish is expected to be able to produce tags relating to each fish and details of its purchase upon request. Without this information, an illegally caught fish becomes just another salmon and cannot be sold as wild.

Now a single laboratory test can reveal whether a salmon is a farmed or wild fish.

‘Most farmed salmon are from Norwegian stock and have a highly distinctive genetic fingerprint. The research at Exeter University shows there are clear differences in the DNA of salmon returning to UK rivers like the Exe and fish with a Norwegian genetic signature found at fish farms. By comparing samples against a data base of salmon from across Europe it is possible to tell whether a fish is a farmed or wild salmon,’ said Nick Maye for the Environment Agency.

‘This is an exciting new development that should make enforcement of the Salmon and Freshwater Fisheries Act easier and help us protect salmon stocks around our coasts and estuaries. It has given us another string to our bow and should make anyone selling illegally caught salmon and sea trout think twice before trying to pass off an illegally caught wild salmon as a farmed fish,’ said Nick Maye.

The Environment Agency will be stepping up it checks on local retail outlets to ensure they keep within the law. “We can turn up unannounced at shops and restaurants, ask for details of any fish advertised for sale and, if necessary, take samples for subsequent genetic analysis. Test purchases will also be made anonymously from wet fish premises and samples analysed at Exeter University. Our message to anyone thinking of trading in illegally caught wild salmon is, ‘It is not worth the risk’ because we now have the technology to catch and prosecute you,” said Nick Maye.

Issued by the Environment Agency: 14-Nov-2012