Impact of a climate regime shift on the migration of Japanese common squid (Todarodes pacificus) in the Sea of Japan

Abstract

Following a climate regime shift (RS) in 1989 in the northwest Pacific and Sea of Japan, the main spawning grounds of the Japanese common squid (Todarodes pacificus) shifted from inshore areas off Honshu Island to the Tsushima Strait, and the stock size increased. Migration patterns of T. pacificus occurred after the RS, based on tagging experiments conducted in July to September of 1984 and 1987-1991, are examined using monthly shifts in average latitude of recapture sites every 10 d. Before the RS, recaptures were in the central Sea of Japan and in inshore areas off Honshu Island, but after the RS, there were no recaptures inshore off Honshu Island. The average latitude of the recapture sites in September was about 36-37°N before the RS and north of 40°N (near the release sites) after the RS. It is likely that the location of the spawning grounds has changed. © 2010 International Council for the Exploration of the Sea. Published by Oxford Journals. All rights reserved.