Audacious poachers are at work on the banks of the River Tees in Barnard Castle, putting mammals such as otters at risk.
The Environment Agency confirmed that it pulled nine traps from the River Tees between the town and Egglestone Bridge recently.
David Shears, senior fisheries enforcement officer, is urging members of the public to act as eyes and ears to prevent otters, hedgehogs and birds getting tangled in nets left for crayfish and eels.
“We want to increase awareness,” he told the Teesdale Mercury. “We have our own patrols, but we can’t be everywhere at once.
“A big part of what we rely on is the public’s awareness and vigilance, people reporting anything that looks suspicious to them.”
Information from the public helps the Environment Agency target patrols to where they are needed, confirming where poaching is taking place and removing nets before they can do more harm.
And since unauthorised nets and traps are illegal, anybody caught can find themselves in court.
A recent case in Northumberland saw a man from Newcastle ordered to pay almost £700 after he was caught illegally fishing for crayfish in the River Blyth.
“We don’t authorise these in the North of England, full stop,” said Mr Shears. “These traps are indiscriminate when it comes to small mammals and birds.
“Then these were half exposed, which sees land mammals getting caught in there.
“These are detrimental to the river as a whole and, first and foremost, it’s illegal.”
Most of the traps pulled from the Tees recently are targeting crayfish, fuelled by a commercial market for them as well as concerns over the rise of the invasive non-native species.