海洋環境変化と天売島に繁殖するウトウの採食生態

摘要

Rhinoceros auklet Cerorhinca monocerata is a medium sized alcid, breeding in temperate waters in the North Pacific. The largest colony in the world exists on Teuri Island in 28 km off Haboro, northern Hokkaido (about 300,000 pairs). In the Sea of Japan, marine ecosystem is strongly affected by the seasonal northward expansion of Tsushima Warm Current. Basing on seabird monitoring works since 1984, chick diet of Rhinoceros Auklet well reflected decadal, inter-annual, and seasonal scale change of strength of Tsushima Warm Current. Especially, the seasonal availability of the warm water living Japa-nese anchovy Engraulis japonicas that was driven by the current strongly affected breeding performance of Rhinoceros Auklet.