Acoustic surveys of walleye pollock by Hokkaido Research Organization using the quantitative echo sounder (review)

Walleye pollock is one of the most important resources of commercial fisheries in Hokkaido. Annual landings of this species are controlled by the Total Allowable Catch system in Japan. Because the annual landings have decreased since the late 1980’s, more intensive studies for stock assessment, forecast of fishing conditions and developing a proposal for sustainable resource management are required for the stake-holders. In this review, I describe the history and results of acoustic surveys using a quantitative echo sounder for walleye pollock conducted by Hokkaido Research Organization to respond to such needs.