Pictures highlight problems with photo ID

This 4lb 8oz specimen could easily have been a contender for the roach record under different circumstances.

The photographs of the fish, caught on maggot feeder tactics by Gary Ashwell while he was targeting noted Northamptonshire specimen water Hollowell Reservoir for big bream, clearly highlight the problems associated with identifying fish without genetic evidence.

The water has a history of producing roach/rudd hybrids, and that is what Gary believed he had caught once he got the fish on the bank. But the two photos he sent in to Angling Times provoked different interpretations from experts whose opinions are now polarising towards the need for DNA tests to distinguish hybrids from the real deal.

“I’ve had a quick look, and it’s very close to being a roach. I don’t suppose there are any more images?” was fish ID expert Nigel Hewlett’s initial reaction at seeing the close-up photo.

But on seeing more details in the second image, Nigel instantly revised his opinion.

“Based on the second photo, it’s clearly a roach/rudd hybrid. I think these photographs demonstrate the difficulties of identifying roach from images alone. The first, I was just about able to convince myself, was 99 per cent roach, the second clearly shows rudd traits,” he concluded.

Another angler who has read all the scientific papers on fish ID is former Drennan Cup winner Andy Nellist, who also sits on the British Record Fish Committee with Nigel. Reassuringly, both seem to be singing from the same song sheet.

“It’s got strange lips and there are few rays in the dorsal, but it looks pretty roachy. The lateral line is strong and the count in the right range.

However, the fins are very red and the eye a bit yellow, but such colours do occur in roach. If I’d caught the fish I’d definitely have taken a scale sample,” was Andy’s initial reaction.

“Having seen the second photo, I’d say it’s a hybrid. It shows just how difficult it is to make a call on photo evidence alone,” he said.

The pair’s conclusions were supported by other scientists whose opinions support the argument for claims of big specimens of hybridising species such as roach, rudd, crucians and silver bream to be supported by a scale sample for DNA testing.

“ID from photos is notoriously unreliable, particularly for hybrids. There are genetic markers now available, so a single scale will now give a definitive answer,” said Sparsholt lecturer Dr Mark Burdass.

“Genetics is the way to go. Taking a single scale sample from a potential record-shaker makes sense providing a sensible protocol for removing said scale is advertised on the internet, say by the Angling Trust in support of the BRFC,” said fisheries consultant Dr Bruno Broughton.