Ruffe

The ruffe (Gymnocephalus cernua), also known as the Eurasian ruffe or pope, is a freshwater fish found in temperate regions of Europe and northern Asia. It has been introduced into the Great Lakes of North America as an invasive species and is causing unfortunate results as it is reproducing faster than other species. Its common names are ambiguous – "ruffe" may refer to any local member of its genus Gymnocephalus, which as a whole is native to Eurasia.

Distribution

The species occurs in the basins of the Caspian, Black, Aral, Baltic and North Sea, and is also found in Great Britain, parts of Scandinavia and some regions of the Arctic Ocean basin eastward to the drainage of the Kolyma. It has been introduced to parts of Western Europe (France, northern Italy) and Greece, as well as to the North American Great Lakes.

Behaviour

In Eurasia, the ruffe diet mainly consists of zoobenthos: chironomids, small aquatic bugs and larvae, which are all found in the benthic zone of the water column. As far as researchers have been able to learn, it has kept the same diet in its transfer to the Great Lakes.