Results of the Japanese dedicated cetacean sighting surveys in the North Pacific in 2021/2022 spring, autumn, and winter seasons
Taiki Katsumata, Futoshi Yamaguchi, Isamu Yoshimura, Reiko Nagata, Seiichiro Teruya, Kosuke Maehashi, Nana Sawada, Riki Ohmukai, Shinya Kawabe, Koji Matsuoka
Systematic large-scale vessel-based sighting surveys were conducted in 2021/2022 by Japan to examine the
distribution and abundance of large whales in the western North Pacific. In these years, the surveys were conducted
in spring, autumn and winter seasons. Previous information on distribution and abundance in these seasons is poor.
The research area was set between 35oN-46oN and 141E-150oE. The surveys were conducted between 10 April 2021
and 18 March 2022. The research vessels Yushin-Maru, Yushin-Maru No.2 and Kaiyo-Maru No.7 were engaged in
the surveys. A total of 4,956.3 n.miles was searched by the passing mode in the research area. In total, seven large
whale species including fin (50 school /70 individual), sei (27/31), Bryde?s (164/201), common minke (17/18), North
Pacific right (1 /1), humpback (70/87) and sperm (168/479) whales were sighted during whole research. Experiments
on photo-id, biopsy and satellite tracking were conducted to obtain data and samples for future studies on the
distribution, abundance and stock structure of large whales.