Smallmouth Bass

19 Sep Smallmouth Bass

Smallmouth Bass / Kokuchi Basu
Micropterus dolomiu (Lacepede, 1802)


Initially imported from North America along with largemouth bass by early day lure angler into Lake Ashino in 1925 and became extinct. Then they were found adopting to Japanese environment in Lake Nojiri, Hibara, and Kizaki in 1990’s. Now smallmouth bass can be found in waters in the coldwater of Honshu Island.


Smallmouth bass can be found in Tama River and Iruma River near Tokyo, but they are only scarcely populated. Flourishing habitats are Lake Nojiri in Nagano or Lake Hibara in Fukushima.

How North American Fish Spread So Wide? 

Bass fishing was hot spot for new business development in the 1970’s and 1980’s when lure fishing became popular in Japan. It is confirmed that the import & distribution industries for pet and fishing tackle had been quite active in importing game fish during this time when those North American fish began to be spotted in waters near populated area in Honshu Island.

Japan has tradition of “Yushi Horyu” or volunteer stocking by anglers who go anywhere awkward to stock the water. Also, there are plenty of hatchery and fish farm. All combined, I imagine spreading few specie nationwide wasn’t all too difficult.

Today’s Regulation

The Act of Alien Specie prohibits transportation and cultivation of the specie without permission by local government.