Radiocesium contamination of cetaceans stranded along the coast of Hokkaido, Japan, and an estimation of their travel routes

Marine Ecology Progress Series

Takashi Matsuishi¹  Mari Kobayashi¹  Ayaka Matsuda¹  Tetsuya Endo¹  Osamu Kimura¹  Tuguya Nakamura¹ 

关键词: 134Cs;    137Cs;    Lagenorhynchus obliquidens;    Phocoena phocoena;    Phocoenoides dalli;    Balaenoptera acutorostrata;    Megaptera novaeangliae;   

DOI  :  10.3354/meps11432

学科分类：海洋学与技术

来源: Inter-Research

【 摘 要 】

ABSTRACT: We analyzed radiocesium (¹³⁴Cs and ¹³⁷Cs) levels in the muscle tissue of several odontocetes and mysticetes stranded on the coast of Hokkaido (the northernmost island of Japan) in 2011 and 2012, following the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident in March 2011. Since most of the radiocesium from the FDNPP was released into the western North Pacific Ocean and carried eastward from the Japan coast, there was little radiocesium contamination in the seawater around Hokkaido. Hokkaido is surrounded by the North Pacific Ocean, the Japan Sea, and the Okhotsk Sea, but radiocesium was predominantly detected in the cetaceans stranded along the North Pacific coast between June and October 2011. Among the stranded cetaceans, which included the Pacific white-sided dolphin, harbour porpoise and Dall’s porpoise (odontocetes) as well as the common minke whale and humpback whale (mysticetes), the highest level of contamination was found in a common minke whale. The radiocesium contamination of these cetaceans suggests that they moved seasonally from the south of Hokkaido, particularly through the contaminated area of the western North Pacific Ocean. The radiocesium levels in the tissues of these animals is likely a result of the contamination level of the seawater along their travel route, rather than their trophic level, because of the sudden changes in radiocesium transport and diffusion in seawater that occurred in 2011.

【 授权许可】

Unknown