Crayfish ’trapping’ fails to control invasive species

Despite being championed by a host of celebrity chefs, crayfish 'trapping' is not helping to control invasive American signal crayfish, according to new research by UCL and King's College London. There have been grave concerns within the science community and amongst conservationists that American signal crayfish are wiping out other species of crayfish across Europe - including Britain's only native crayfish, the endangered white-clawed crayfish. In their new study, published in the Journal of Applied Ecology , the researchers find that trapping is ineffective in determining and controlling signal crayfish numbers, as the vast majority of individuals are too small to catch using standard baited traps. 'Trapping to eat' American signal crayfish has been promoted as a potential control measure in recent decades, but scientists warn that this method may exacerbate the problem, as it inadvertently incentivises 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. Co-author and PhD researcher, Eleri Pritchard (UCL Geography), said: "Invasive signal crayfish from the US were introduced to England in the 1970s. Since then they have spread rapidly, displacing native crayfish, impacting fish and damaging ecosystems." "While celebrity chefs and conservation charities have, with good intentions, promoted trapping and foraging as a way to control American signal crayfish, our research shows trapping to be ineffective.