Native to Southeast Asia, the Chinese mitten or hairy crab (Eriocheir sinensis) is thought to have arrived in Europe in ballast water. It ranks as among the 'world's worst' invaders. First recorded in the Aller River in Germany in 1912, the crab is now abundant in European estuaries adjacent to the North Sea and Baltic Sea. The invasion has damaged biodiversity, with loss to commercial fisheries and pond-aquaculture, and caused erosion to river embankments through burrowing. A positive effect, however, is the crab's market value – they are considered a delicacy.