Cetacean fauna, abundances and population dynamics in Okhotsk Sea, with some notes on future prospect of their conservations and managements.

Hidehiro KATO¹⁾, Tomio MIYASHITA²⁾ and Yoshihiro FUJISE^3)
1) Tokyo University of Marine Science and Technology, Tokyo, Japan
²⁾ National Research Institute of Far Seas Fisheries, Yokohama, Japan
³⁾ The Institute of Cetacean Research, Tokyo

Abstract.

Japan has been conducting systematic cetacean sighting survey in western North Pacific including Okhotsk Sea since 1989. Through those cruise a total of 11 cetacean species have been identified, whose richly cetacean fauna were especially noted. Of those data sets for four species were good enough qualities for abundance estimation as being 19,200 (CV 0.31) for minke whales, 5,000 (CV0.32 ) for fin whales,  920 (CV 0.43) for right whales, 443,000 (CV 0.11) for Dall’s porpoises which allow some population analyses incorporating ecosystem aspects, and we preliminary examine direction of ecosystem modeling approaches in Okhotsk Sea and adjacent waters. Because Okhotsk Sea provides very important habitats not only as feeding grounds for most of species but also as breeding grounds for some species, future prospect of their conservation and management are discussed.