Professor Leonid Ryzhkov at the University of Petrozavodsk fears that the main populations of fish in the Lake Onega can be faced with extinction after the Chinese mitten crab has been found in the lake, RIN writes.
The crab is very invasive and can reach a high number in only ten years time. - If the crab is left to spread in Lake Onega it will become a real threat to the Karelian fishing industry, Ryzhkov underlines.
The Chinese mitten crab lives in both fresh and sea water and can also make significant inland migrations.
The Chinese mitten crab was found in the White Sea near Arkhangelsk in 2010, with scientists suggesting it could have walked there in the rivers from the Baltic Sea through the lakes of Ladoga and Onega.
This species is very invasive and has been spread to North America and Europe, raising concerns that it competes with local species. The crab is known to have a negative impact on the fishery industry by getting stuck to fishing nets and eating fish and bait. Mitten crabs, where present in large numbers, can block the cooling systems of power stations. They also burrow into river banks, causing them to become unstable and collapse.
Another serious concern is that they have the potential for bioaccumulation of toxins, which makes it a potentially toxic food source for aquatic predators and humans. The mitten crab is also be the secondary host for the Asian lung fluke (Paragonimus westermani), which causes disease in humans and animals. In Asia, where mitten crabs are a delicacy, people regularly suffer lung damage from eating infected mitten crabs, according to Wikipedia.
In the 1960s another invasive crab type was introduced in the Arctic – the red king crab. Since then, the population has grown immensely. Some estimates say there are more than 20 million in the Barents Sea. Many environmentalists and scientists say the species negatively alters the sea’s natural biodiversity.