Dear MARMAM, On behalf of the first author, I would like to announce a new publication.
Ishii, M., Murase, H., Fukuda, Y., Sawada, K., Sasakura, T., Tamura, T., BANDO, T., Matsuoka, K., Shinohara, A., Nakatsuka, S., Katsumata, N., Okazaki, M., MIYASHITA, K., Mitani, Y., 2017. Diving Behavior of Sei Whales Balaenoptera borealis Relative to the Vertical Distribution of Their Potential Prey. Mammal Study 42(4), 1–9. doi:10.3106/041.042.0403 Abstract. In this study, we investigated the diving behavior of sei whales relative to the vertical distribution of their potential prey in the western North Pacific during the summer of 2013. Acoustic time-depth transmitters were attached to two sei whales for 10.2 and 32.0 h, respectively. The vertical distribution and density (expressed as the volume backscattering strength, SV) of their potential prey were recorded by an echosounder. Diving behavior was classified into two shapes: U-shaped and V-shaped. For both individuals, U-shaped diving was associated with higher SV values than V-shaped diving and the frequency of U-shaped diving increased from late afternoon until sunset. During the daytime, dense scattering layers (presumably zooplankton) were distributed at approximately 40 m and they then migrated toward the surface around sunset. The diving depth of the whales followed the diel migration of the scattering layers and the diving was concentrated in these layers when the density became high. The results of this study indicate that sei whales change their diving depth and shapes in response to the diel vertical migration of their potential prey. http://www.bioone.org/doi/10.3106/041.042.0403 To request a pdf copy please email Midori Ishii at: [email protected] All the best, Yoko -- 三谷曜子 Yoko Mitani 北海道大学北方生物圏フィールド科学センター 水圏ステーション 函館臨海実験所 生態系変動解析分野 〒040-0051 北海道函館市弁天町20番5号 函館市国際水産・海洋総合研究センター内219号室 Tel: 0138-85-6558; Fax: 0138-85-6625 Email: [email protected] Yoko MITANI Laboratory of Marine Ecosystem Change Analysis Hakodate Marine Station, Field Science Center for Northern Biosphere, Hokkaido University Hakodate Research Center for Fisheries and Oceans 20-5 Benten-cho, Hakodate, Hokkaido 040-0051, JAPAN TEL: +81-138-85-6558; FAX: +81-138-85-6625 E-mail: [email protected] _______________________________________________ MARMAM mailing list [email protected] https://lists.uvic.ca/mailman/listinfo/marmam
