In the laboratory, Bower & Sakurai (1996) observed
that Todarodes pacificus females rest on the bottom
just before spawning. Similarly, bottom trawls often
collect exhausted, spent females on the shelf and slope
at 100 to 500 m depth (Hamabe & Shimizu 1966), indicating
that spawning females would concentrate at
depths between 100 and 500 m. Thus, topography may
affect squid distribution. The main autumn and winter
spawning grounds form around the Tsushima Strait
(Murata 1989, and present Fig. 2). Kiyofuji et al. (1998)
identified the inshore area of Korea’s east coast as a
possible spawning ground, primarily using satellite
SST and topography data. Class 5 corresponds to this