Oyster Culture in Hokkaido, Japan

The Pacific oyster, Crassostrea gigas is the one of the most commercially important aquaculture species in the Japanese fisheries industry and is cultured in various Japanese coastal areas including Hokkaido. The Saroma Lake and the Akkeshi Bay with estuary, which face Ohotsuku Sea and Pacific Ocean, respectively, are major oyster production areas in Hokkaido with total annual production of about 700 tons a year. The seedling spat supplied from Miyagi known as Miyagi seedlings are widely used in Japanese oyster culturing. Therefore, when the catastrophic tsunami on March 11, 2011 damaged the Miyagi fisheries, many oyster culturing areas were heavily affected. Moreover, introduction of seedlings from geographically separated population have risks of invasion of diseases and alien organisms as hitchhiking species. Using seedlings that originated from local populations in each area is one of the approaches for decreasing some risks. For example, in the Akkeshi area, the artificial seedling spats collected from the locally protected adults are also used for aquaculture, which are marketed as the value-added oysters with shell “Kaki-Emon” and popular among consumers as local special products.