Feeding Strategies and Prey Consumption of Three Baleen Whale Species within the Kuroshio-Current Extension

• Main Authors: Kenji Konishi, Tsutomu Tamura, Tatsuya Isoda, Ryosuke Okamoto, Takashi Hakamada, Hiroshi Kiwada, Koji Matsuoka, T. Tamura, T. Isoda, R. Okamoto, T. Hakamada, H. Kiwada, K. Matsuoka
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: CCA; feeding habits; Japanese anchovy; mackerels; Pacific saury Upload date 20 Aug 2009; Pacific; baleen whale; baleen whales; Copepods
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.490.3022; http://journal.nafo.int/42/konishi/3-konishi.pdf

Feeding strategies and prey consumption of three baleen whale species within the Kuroshio-Current extension. J. Northw. Atl. Fish. Sci., 42: 27–40. doi:10.2960/J.v42.m648 Stomach contents from 740 common minke, 393 Bryde’s and 489 sei whales in May-September during 2000-2007 off the Pacific coast of Japan were examined during the Second Phase of the Japanese Whale Research Program under Special Permit in the western North Pacific (JARPN II). Stomach contents analysis showed that the three whale species are highly dependent on small pelagic fish, i.e. Japanese anchovy, Pacific saury and mackerels in addition to copepods and euphausiids. Pianka’s niche overlap index showed high diet overlap among whale species that occur in some areas where they feed on pelagic fish. Canonical correspondence analysis (CCA) indicated environmental and biological factors significantly contribute to the diet composition of whales. CCA also explained the distribution patterns of whales in relation to SST, chlorophyll a concentration and geographical variation. These analyses demonstrated that the diet composition of the baleen whales is determined by spatio-temporal environmental factors and the amount of small pelagic fish carried by the Kuro-shio Current. The total seasonal prey consumption by whales in the study area was estimated to be 774 000 t of Japanese anchovy (16 % of the consumed biomass), 44 000 t of Pacific saury (1 % of the consumed biomass), and 140 000 t of mackerels (14 % of the consumed biomass), indicating these baleen whales are important components in the ecosystem, and warrant inclusion in fisheries assess-ments.