Okhotsk Sea ecosystem: Fishery production and research activities in Japan-Russia adjoining area
Orio Yamamura1), Kaoru Hattori1) and Mari Kobayashi2)
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.