セミクジラ
Review of more than 3,600 North Pacific right whale calls detected by passive listening devices between 2000 and 2006 strongly suggests that the whales migrate into the southeast Bering Sea in late spring and remain until late fall. The earliest were in late May and the latest in December. The peak calling period was July through October. Most were detected from shallow shelf sites within the designated Critical Habitat area. From October through December 2005, several calls were detected at the northwestern middle-shelf and the deeper shelf sites, suggesting that they may appear at different seasons and during migration.