Rivers flowing in Sarufutsu Town of Souya Region, Hokkaido are habitats for Japan’s largest freshwater fish, “Itou” or the sea-run taimen (Hucho Perryi), a critically endangered species designated as such by the International Union for Conservation of Nature (IUCN) and Japan’s Ministry of Environment. Although sea-run taimen historically lived in northern mainland Honshu as well, their populations dramatically dropped due to check dam construction, channelization, and revetment work, etc. Currently, they only inhabit 11 river systems in Hokkaido with many of them found especially in the Sarufutsu River. The population in that river has hardly changed at least for the past twenty years because its upstream reaches, serving as their spawning sites, are rich in riparian forests with large-sized trees. Also, its middle to lower reaches meander and gently flow through wetlands and wildernesses necessary for the growth of taimen and lagoons near the estuary provide taimen with their important feeding sites.

In the Sarufutsu River basin, Oji Paper Co., Ltd. owns 17,290 hectares of the Sarufutsu forest, a significant portion for conserving sea-run taimen. Therefore, it is indispensable for us to work with Oji Paper Co., Ltd. Having been managing its company forest in consideration of biodiversity conservation, Oji Paper Co., Ltd. has taken a further step and established the Environmental Conservation Forest within its timber land for the purpose of conserving the sea-run taimen in response to a joint proposal from the Wild Salmon Center, a NGO based in Oregon, the U.S. engaged in conserving wild salmonids internationally, and the Sarufutsu Itou no Kai based in Sarufutsu Town.

Conserving taimen in Sarufutsu definitely requires cooperation with forest owners such as Oji Paper as well as the central and municipal governments. Also essential are research and studies on the biology and habitat environment of sea-run taimen by researchers and students, and educational activities through symposiums and nature schools.

Aiming to promote the conservation of the sea-run taimen in Sarufutsu through these activities, we have launched the “Sarufutsu Itou Conservation Council” with the participation of interested individuals and organizations.