Result of the Japanese dedicated cetacean sighting survey in the western North Pacific in 2017
Koji Matsuoka, Takashi Hakamada, Yu Ueda, Takashi Kominami, Nobuo Abe, Chikamasa Ohkoshi and Tomio Miyashita
International Whaling Commission
A systematic large-scale and vessel-based sighting survey was conducted in 2017 by Japan to examine the distribution and abundance of large whales in the western North Pacific. The research area was set between 34° N and 45° N and between 140° E and 150° E (sub-areas 7CN and 7CS for common minke whale). The survey was conducted between 28 April and 27 May. The research vessels Yushin-Maru and Yushin-Maru No.3 were engaged. A total of 2,022.6 n.miles was searched by the passing mode in the research area. Coverage of the searching efforts of the planned cruise track line was 82.3% for the 7CN and 92.4% for the 7CS, respectively. In total, five large whale species including fin (3 schools / 3 individuals), Bryde’s (7/7), common minke (24/25), humpback (15/16), North Pacific right (1/1) and sperm (19/41) whales were sighted during the cruise. Photo-ID images was collected from humpback (16 individuals) and North Pacific (1) whales. Biopsy skin samples using a Larsen system were collected from fin (1), humpback (7) and North Pacific right (1) whales, respectively. The sighting data submitted to the IWC secretary based on the SC guideline and will contribute to the work on management and conservation of large whales by the IWC SC.