Okhotsk Sea ecosystem: Fishery production and research activities in Japan-Russia adjoining area

Orio Yamamura¹⁾, Kaoru Hattori¹⁾ and Mari Kobayashi^2)
1)Hokkaido National Fisheries Research Institute, FRA ²⁾Tokyo University of Agriculture

Abstract.

The Okhotsk Sea coast of the Hokkaido Island, extending as long as 700 km (excluding the Northern Territories), yields 30 - 40 % and >10% of total fishing production in Hokkaido Island and Japan, respectively. The total fishery production in this area has been rather stable fluctuating between 0.4 - 0.5 million metric tons in the last two decades. However, the major species has changed gradually from walleye pollock to scallop and salmon. In the early 1980s, the catch of walleye pollock exceeded 0.2 million tons decreased to 30 - 40 thousand tons by the mid-1990s. The catch of salmon (mainly chum salmon) and scallop supplemented the decrease, accounting for >80% of total catch in the last decade. The decrease of walleye pollock is accountable mainly to the shrink of the fishing ground in the Russian EEZ, rather than collapse of the fishing stock. The increases in scallop and salmon are accountable to the prevalence of stock enhance programs (both species) and declining of the high-sea gillnetting in the 1980s (salmon).

In the Japanese EEZ of the Okhotsk Sea, an annual stock survey has been carried out for demersal stocks including walleye pollock and king crab. However, both species are distributed widely in the Okhotsk Sea extending far north of the Japanese EEZ, making it difficult to monitor the status of the entire stocks. So a cooperative survey with Russia is anticipated. Pinnipeds, including seals, fur seal and Steller sea lion, are causing more conflicts with fisheries in the Hokkaido waters. We also mention Japan-Russia joint survey for pinniped rookeries recently made in the Russian waters.