Eighth species of American crayfish found in Dutch rivers

A new species of crayfish has been found in Dutch rivers, the eighth type to establish itself in the Netherlands after being introduced in the upper Rhine.

The calico crayfish (Faxonius immunis), originally from North America, was spotted in Gelderland by ecologist Pim Lemmers, who first encountered the creatures in a nature reserve near Karlsruhe decades ago.

“I’d been expecting them and looking out for them for a while,” he told NOS. “Last year I found a crayfish pincer and I knew straight away that it might be a significant one.“

The discovery of the pincer, together with the results of DNA samples, are enough to confirm that the crayfish have made it to the Dutch river system.

The water authority in Rivierland has reported the presence of the crayfish to the food standards regulator NVWA, which will in turn notify the European Union, and triggered the protocol for dealing with invasive exotic species.

The Dutch agriculture ministry has set up a working group to investigate how the crayfish can be prevented from spreading. Crayfish damage the local environment by eating indigenous plants and animals and digging in river banks.

“We’re at a very uncertain stage, because are they just in the Klompenwaard area of the Rhine or are they already in our regional waters? Can we keep them out of the waters?” said José Vos, senior policy adviser for the water board.