‘We started eating them’: what do you do with an invasive army of crayfish clones?

It's been dubbed the perfect invader, but the marbled crayfish may offer a sustainable food source and even help prevent disease

Small, bluish-grey and speckled, it would be easy to overlook the marbled crayfish. Except for the fact it is likely to be coming to a pond or river near you soon - if it is not already there. The all-female freshwater crustacean has become a focus of fascination for scientists in recent years, due to its unique ability among decapods - the family that includes shrimps, crabs and lobsters - to clone itself and quickly adapt to new environments, as well as the fact that it has spread exponentially.

The marbled crayfish was first recognised in 1995, when a biology student bought a bag of crayfish - sold to him as Texas crayfish" - from American traders at a pet fair in Frankfurt. After becoming a burden to their new owner due to their inexplicably rapid rate of reproduction, he distributed them to friends who, in turn, dumped them in rivers, lakes and toilets, from where they spread rapidly, throughout Germany, much of mainland Europe and most profusely, the island of Madagascar, home to unique but extremely delicate freshwater ecosystems.