Cruise Report of the New Scientific Whale Research Program in the western North Pacific (NEWREP-NP) in 2018 â€“Offshore component
Kenji Konishi, Kazuyoshi Nakai, Jun Kanbayashi, Kengo Umeda, Miyuki Kanaiwa, Hiroya Mure, Seiichiro Teruya, Masaomi Tsunekawa, Shinya Kawabe, Hiroshi Eguchi and Tsutomu Tamura
This paper reports the results of the second biological survey of sei and common minke whales under the New Scientific Whale Research Program in the western North Pacific (NEWREP-NP)-offshore component. The survey was conducted in part of sub-Areas 7 (7WR and 7E), 8 and 9, north of 35Â°N from May to August 2018. Two sighting sampling vessels (SSVs) and one research base vessel were engaged in the survey for 90 days. A total of 48 sightings (involving 50 individuals) of common minke whale and 289 sightings (involving 413 individuals) of sei whales were made during 6,422 n.miles of searching distance. A total of 43 common minke whales and 134 sei whales were sampled as originally planned. Sei whales were all sampled along the predetermined tracklines in the Normal survey which was designed in a systematic way, and common minke whales were sampled along both the Normal survey and the Special survey track lines which were designed for areas where the density of common minke whales was expected to be high. Overall searching effort was optimized and the research area was covered adequately. Biological samples and data required for the two primary objectives of NEWREP-NP were obtained from each whale sampled. In particular earplugs for age determination and reproductive organs for sexual maturity determination were collected from all individuals. Preliminary biological analyses were conducted and results are presented in this paper. Sardine and mackerels were major prey species for sei and common minke whales. Three blue whales were photo-identified, and biopsy samples were collected from one blue, seven sei and one common minke whale. Satellite tags were deployed on 8 sei and one common minke whale and the locations were obtained for all of these individuals. The samples and data collected in this survey will be available for interested national and international scientists under the guidelines for research collaboration in NEWREP-NP.