Chippies sell catfish as 'traditional fish supper'

Rogue chip shops have been passing off catfish as "traditional fish and chips" to cut down on costs, the BBC has learned.

Cases of fish being mis-sold or misdescribed are often hard to detect since any investigations are intelligence-led and rely on expensive DNA testing.

A BBC North West investigation found a catfish species, known as pangasius or river cobbler, being sold in the region's chippies without customers being fully aware of what they were buying.

The Chartered Trading Standards Institute said that while the mis-selling or misdescription of fish was not a widespread issue it acknowledged "there are still some unscrupulous businesses".

Catfish, which is safe to eat, is generally farmed and imported from South East Asia.

It is significantly cheaper, at about £3.40 per kilogram wholesale, than traditional species such as cod and haddock which typically go for £15 per kilogram.

The investigation was prompted by the owner of a Liverpool chip shop contacting the BBC to complain about the dishonest practice.

"This goes on more than you'd think and it's putting people like me at a disadvantage," he said.

The BBC analysed dozens of online food reviews in which customers questioned the species of fish that they had bought.

Many of them left comments such as "haven't a clue what type of fish it was" and "not cod or haddock, some cheap white fish".

The reviews led the BBC to identify 10 businesses, five in Liverpool and five in Manchester, for a sample test.

Three of the chip shops that our reporter visited listed cod on the menu, four listed haddock and three listed just "fish".

If asked, a business is legally obliged to inform a customer of the species.

The three which did not list a species told the BBC they were "normal fish" or "white fish".

In one case the server gestured to a sign which said "traditional fish and chips".

DNA testing at Liverpool John Moores University revealed that all three takeaways had sold catfish.

Professor Stefano Mariani, who oversaw the tests with his colleague Catherine Perfect, said: "We used DNA barcoding to identify the species, and we found three out of the 10 samples were pangasius - often known as river cobbler on the market, a type of tropical freshwater catfish."

Mariani told the BBC: "In my experience with fish and chips, three out of 10 is quite a lot - I don't recall seeing this level of catfish."

The portions of catfish were bought for £3.80, £4.20 and £5.

Servings of cod or haddock were sold for between £4 and £6.

Asked whether a customer could tell the difference, Mariani said: "It is very difficult for a member of the public that is not a trained fish biologist to identify one fillet from another."

National Trading Standards told the BBC that fish being sold under the wrong name was a "food labelling issue".