Abstract
Rainbow (Oncorhynchus mykiss) and brown trouts (Salmo trutta) were introduced to Hokkaido in 1920 and 1978, respectively. Catch records of rainbow and brown trout in Hokkaido were obtained from data reported in a monthly angling magazine and the Annual Reports of the Hokkaido Fish Hatchery. Rainbow trout have been caught in 72 river systems during 1970 to 1996. Brown trout were discovered in 1980, have widely extended their distribution in recent years, and have been caught in 18 river systems in Hokkaido.
