Mitten Crabs Invading Britain

Thanks to a decrease in river pollution over the last few decades, an exotic crab is spreading at an alarming rate throughout Britain's coast and rivers, a new study suggests.

The Chinese mitten crab--so called because its claws are coated with small mitten-like clumps of dark brown fur--could cause devastating environmental problems if populations are not monitored and controlled, say the study's authors.

Researchers from the University of Newcastle upon Tyne carried out the first comprehensive modeling of the crab's migration through Europe and the UK. They found the pattern of the crabs' ongoing invasion of the UK is similar to the population expansion in Europe earlier in the last century when the Continent experienced a major outbreak.

The study authors predict that the mitten crab, which stowed its way to Britain during the last century in ships' ballast water, has the potential to establish itself in all major UK estuaries in several years time.

Mitten crabs are unwelcome because they prey on protected UK native species such as the white-clawed crayfish and salmon eggs and fry. They also settle in river banks, burrowing into them and riddling them with bore holes up to half a metre long which may eventually cause the bank to collapse.

The Newcastle University study, published in the academic journal Biological Invasions, recommends that a nationwide monitoring and trapping system for the crab should be introduced before it is too late to control the population.

--LiveScience Staff