The invaders-parasites, which penetrated the territory of Russia 20 thousand years ago and were successfully hiding until recently, were exposed by Russian scientists. This is a species of the mollusk leech Batracobdella kasmiana, never seen before in our water bodies.
As MK was told at the Northern Arctic Federal University, it was believed that these leeches, which belong to the category of annelids, were widespread in Japan and China. Until recently, they were not seen in our rivers. As it turned out now, only because these parasites hid well inside the shells of toothless and pearl barley – large bivalve molluscs. Recently, studying these freshwater species in the Razdolnaya River near Vladivostok and the Gladkaya River in the Khasansky District of the Primorsky Territory, biologists have discovered insidious invaders. Experts have counted up to 50 “eastern” leeches in each mollusk. According to the discoverers, this species could have penetrated to the south of Primorye from the rivers of Japan, the Korean Peninsula or northeastern China during the Ice Age (about 20 thousand years ago), when the ocean level was much lower, and the river basins of these regions could communicate.
The found individuals are quite dangerous for the fauna inhabiting there and, accordingly, worsen the ecological situation, because mollusks are good cleaners of rivers and lakes.