Dear All, The following paper is now available. PDF reprints are available upon request (contact email: ymitani@bio.titech.ac.jp "Patterns of stable carbon and nitrogen isotopes in the baleen of common minke whale (Balaenoptera acutorostrata) from the western North Pacific." Yoko Mitani, Takeharu Bando, Noriyuki Takai, Wataru Sakamoto. Fisheries Science72 (1): 69-76 (2006) ABSTRACT Stable carbon and nitrogen isotope ratios were determined in the baleen plates of 17 common minke whales (Balaenoptera acutorostrata) from the northwestern Pacific Ocean off Japan as well as prey species (krill [Euphasusia pacifica], Japanese anchovy [Engraulis japonicus] and Pacific saury [Cololabis saira]) collected in the stomach contents to investigate the trophic relationship between the minke whales and their prey. A few d15N-depleted peaks occurred along the length of baleen plates for 10 males irrespective of stomach contents (anchovies and sauries). Similar d15N-depleted peaks were also found for one female and two immatures. It was likely that these d15N- depleted peaks formed in early summer. The d15N values in Pacific saury (9.3±1.4‰) did not differ significantly from that in Japanese anchovy (8.8±0.9‰). In contrast, d15N in krill (7.2±0.5‰ in July and 8.0±0.2‰ in September) was significantly lower than in Pacific saury. Thus, we expect that these peaks might reflect the dietary change from krill to fishes in the feeding migration of the whales. Growth rate of the baleen plate was estimated to be 129 mm y-1, and it appeared that dietary record of about 1.4 years remained in the baleen plate. For two immature whales, the maximum value of d15N occurred at the tip of baleen. This d15N enrichment may possibly be useful for discriminating weanlings and older whales. Key Words: common minke whales, stable isotopes, baleen, feeding ecology, North Pacific --- Thanks, Yoko Yoko Mitani Faculty of Bioscience and Biotechnology, Tokyo Institute of Technology, 2-12-1 W3-43 Ookayama, Meguro, Tokyo, 152-8551, JAPAN Tel: +81-3-5734-3383 Fax: +81-3-5734-2946 E-mail: ymitani@bio.titech.ac.jp -------------------------------------- Celebrate Yahoo! JAPAN 10th Anniversary http://pr.mail.yahoo.co.jp/10thann/