2002 Volume 68 Issue sup1 Pages 57-62
The freshwater fishes in the northern Far East were investigated to elucidate the species richness, ecological complexity and genetic diversity. The fishes in Hokkaido Island, Sakhalin Island, Primoee and the Amur River basin were composed of 27 families, 83 genera and 130 species which possessed high ecological and genetic diversity. Concerning the freshwater sculpins, for example, one Trachidermus, one Mesocottus and 11 Cottus species are distributed in the regions. The mitochondrial DNA analyses made clear that the amphidromous, lacustrine and fluvial species have originated from the ancestral stocks of catadromous species such as T. fasciatus and Cottus kazika, showing the creation of species diversity. Mainly because of rapid changes of freshwater environments, however, nearly 10-40% fish species to the total number of species distributed in the regions were found to be endangered, indicating the necessity of effective conservation actions.
