For many years celebrity chefs and some environmentalists have encouraged the public to trap and eat the American signal crayfish. The rationale has been that this could serve as a control measure and help reduce the prevalence in UK waters of the introduced species and thereby improve the fortunes of the endangered white-clawed crayfish.
It may even exacerbate the problem.
This is because the vast majority of individuals are too small to catch using standard baited traps. The scientists found that the policy may also inadvertently incentivise members of the public to spread the species to new habitats and greatly increases the risk of accidental catches of the strictly protected native species.