網走湖のベントス相

Lake Abashiri is one of the brackish-water lakes located along the coast of Okhotsk Sea, Hokkaido, northern Japan. The investigation of macrobenthic fauna in Lake Abashiri was done in October 1995, following the first investigation in 1936. Comparing results of this investigation to that of 1936, bottom fauna have changed from freshwater fauna to brackishwater one. Most dominant species is the clam, Corbicula japonica, which is very important fishery resource of this lake. Because of strong stratification of lake water, bottom layer is anoxic, and the distribution of benthic organisms are restricted to shallow oligohaline water region macrobenthic fauna in Lake Abashiri do not include some typical brackish-water species which occur commonly in Corbicula japonica habitat. Possible reasons of the result are discussed.