open access

https://hdl.handle.net/2115/33067

An overview of the Oyashio ecosystem

英語

marine mammals

2007-11

Pergamon

Deep Sea Research. Part 2, Topical Studies in Oceanography

54(23-26)

2526-2542

The Oyashio shelf region and the seasonally ice-covered areas north of Hokkaido are highly productive, supporting a wide range of species including marine mammals, seabirds and commercially important species in the western subarctic Pacific. The fishes include gadids, such as walleye pollock and Pacific cod, and subarctic migratory pelagic fishes such as chum salmon and pink salmon. It is also an important summer feeding ground for subtropical migrants such as the Japanese sardine, Japanese anchovy, Pacific saury, mackerels, Japanese common squid, whales and seabirds. In recent decades, some components of the Oyashio ecosystem (i.e., phytoplankton, mesozooplankton, gadid fish, and subtropical migrants) have shown changes in species abundance or distribution that are correlated with environmental changes such as the 1976/77 and 1988/89 regime shifts. The First Oyashio Intrusion moved northward from the mid 1960s until the late 1970s when it moved southward until the 1980s, after which it returned to the north again after the mid 1990s. The sea surface temperature in spring decreased after the late 1970s, increased after the late 1980s, and remained high during the 1990s. The extent of ice cover in the Sea of Okhostk also decreased during the latest warming in the 1980-90s but has increased again since the late 1990s. These and other kinds of variability are described in this overview of the status of the Oyashio ecosystem and the surrounding region.

学術雑誌論文

Accepted Manuscript

0967-0645

AA10868862