Chinese Mitten Crab Invades Lake Onega

10.01.2012

Китайский мохнорукий крабChinese mitten crab who settled down in the lake of Onega disturbs all the other lake inhabitants. Due to rapid propagation of crabs several local species of fish are almost extinct.

Chinese invader reproduces itself so intensively, that in ten years its population might take over the lake, thus destroying its ecosystem. It happens because mitten crabs nourish on most fish species main food source – or even on fish itself. Crabs also tear fish nets and dig on lake banks and dams, leading them to further demolition. Biologists also warn the locals that this species of crab tends to accumulate toxins, therefore being poisonous for humans and water predators.

Origin of Chinese mitten crab is coastal zone of Yellow Sea. However, this species adapts easily to any environment: it could inhabit either marine or freshwater bodies and stay out of water for a rather long time. Nowadays mitten crab has spread over Europe and North America. Researchers found it in the White Sea. It could get to Onega Lake either with ballast water or attached to a ship bottom. There is also a version that mitten crabs traveled all the way from the Baltic via Ladoga and Onega rivers.

By the way, it’s not the first attempt of mitten crabs to invade the Onega Lake. Previously, it was destroyed by massive catches. Same measure is to be taken this time too.