【今期马会历史开奖记录_今期马会历史开奖记录官网】Invasive species oust original river crayfish in Czech town

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PRAGUE, Aug. 22 (Xinhua) -- The invasive species of spinycheek crayfish (Latin name orconectes limosus) have ousted local original crayfish in the water reservoir of south Czech town Lipno, a researcher said Wednesday.

According to the scientific observation, it may not be excluded that Lipno's local crayfish population is completely extinct. Scientists warn that the invasive spinycheek crayfish may bring some serious danger as they spread crayfish plague.

Being native to the east coast of North America, spinycheek crayfish came to Europe in the 19th century. There are several factors behind the massive spread of this species, according to Pavel Kozak, dean of the Faculty of Fisheries and Protection of Waters of South Bohemian University. Among them there are unprofessional crayfish breeding, which population is also spread by means of fish farming, as well as extreme temperatures. "It is a problem all over the Czech Republic," Kazak added.

The presence of spinycheek crayfish in the freshwater, according to the dean, has a negative impact not only on the ecosystems of the Lipno reservoir, but also on the river tributaries. Growing populations of invasive species put pressure on the original communities of aquatic plants, insects, shellfish, and evolutionary stages of amphibians and fish.

Kozak said that there are already hundreds of thousands of the spinycheek crayfish living in the Lipno reservoir. Scientists first discovered them in this area in 30006.

The Tourist Association of Lipno also wants to address the issue of the invasive species spreading. The chairman of the association Jiri Manek said that based on the research findings, it is needed to initiate a professionally organized rescue program for local crayfish, otherwise, the original crayfish may be completely vanished by the invader.