Environment Agency officer Jez Wood highlighting problem of otters being killed in crayfish traps. Picture: James Bass

Illegally set crayfish traps have caused the agonising death of at least a dozen otters on the Broads in the past three years, the Environment Agency (EA) has warned.

In the latest incident earlier this month, horrified holidaymakers on a boat found a crayfish net with a dead otter inside floating at the entrance to Womack Dyke on the River Thurne at Ludham.

The mammal, an adult male, had suffered deep cuts from the netting in his frantic attempt to escape before drowning.

It is thought the culprit responsible for setting the trap cut it loose when he made the gruesome discovery and that is how it came to be floating on the surface.

The EA has launched a public awareness campaign to combat the problem which has grown with the increasing demand for crayfish - especially the American signal variety - in restaurants.

EA biodiversity officer Jez Wood said: “Although crayfish traps are widely available, consent from the Environment Agency is required in order to set the traps legally.”

He said it was unlikely consent would be granted in such sensitive areas as the Broads and the go-ahead would only ever be given if the traps conformed to strict size dimensions and had an otter guard fitted to prevent the animal getting into the trap.

He said: “Most of the collapsible ‘sprung’ traps are sold with an entrance larger than the legal dimensions. Otters can then enter these traps but cannot escape and drown.”

Mr Wood warned that otters were protected by law and killing them could result in a fine of up to £5,000 or six months in prison.

He said: “It is extremely upsetting to see an otter killed in such a way. Being an aquatic mammal it would have taken some time to drown and would have endured a lot of suffering. This trap was not fit for purpose and should never have been set.”

Trapping signal crayfish created risk not only for otters and other aquatic mammals but also for England’s native crayfish species, the globally threatened and increasingly rare white clawed crayfish.

“Norfolk has some important strongholds for white clawed crayfish, as a result the Environment Agency is very strict about where trapping can be carried out,” he added.

He said the traps could carry spores of the deadly crayfish plague, carried by signal crayfish, and these could wipe out a population of white clawed crayfish which were vulnerable to the disease.

Fishing for eels was also illegal without consent, and fyke nets, unless modified with an otter guard, carried the same risks for otters. One such illegal fyke net was found to contain the skeletal remains of six otters in 2009.

Anyone who suspects that a trap has been set illegally, or has found a dead otter, is asked to contact the EA’s free incident hotline on 0800 807060.

Further details on where crayfish trapping is allowed and the consenting procedure is available from the EA by phoning 03708 506506.