The River Dore is a fantastic habitat for a wide range of species including one whose numbers have plummeted rapidly over the last 25 years - the white-clawed crayfish. There are many reasons for its decline, but one is that the American signal crayfish has come across to this country and brought a disease with it. In addition, the American ones are much bigger than the native crayfish, so they out-compete and even kill them. If you look around under stones on the bottom of the river or under tree roots you might find a white-clawed crayfish. But if you do find one, you shouldn't pick it up because it is a protected species. They don't grow very big, but could still give you a nip with their pincers. The name white-clawed comes from the underside of their claws. The American crayfish is much darker. They rely on camouflage to avoid being eaten by otter and mink. Hopefully the habitat improvement work on the River Dore will increase their numbers.