The
Eurasian ruffe (
Gymnocephalus cernuus), also known as
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, reportedly with unfortunate results, as it is invasive and 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 natively endemic to
Eurasia.