1 School of Fisheries Box 357980, University of Washington,
Seattle, WA 981952 International Pacific Halibut Commission, P. O. Box
95009, University of Washington, Seattle, WA 98145-2009
Recent work (Hare and Francis
1992, Francis and Hare 1994, Hare and Francis 1995, Hare 1996) has shown
that Alaska salmon population production responds to regime scale (interdecadal)
climate forcing, manifesting itself in low frequency and rather abrupt
jumps which correspond very closely to similar abrupt shifts in N. Pacific
atmosphere and ocean climate. Careful analysis reveals that
1. This connection between atmosphere/ocean
physics and salmon production occurs early in the salmon marine life history.
2. To date, connections between
indices of climatic variability and salmon production have been found at
the regime (interdecadal) scale, but not at the interannual scale.
The objective of this paper
is to discuss recent findings on the effects of regime scale climate changes
on upper ocean dynamics and apparent responses in phytoplankton and zooplankton
production in both the California and Alaska Current regions of the NE
Pacific. These results have major implications concerning mechanisms linking
the observed decadal scale climate response of NE Pacific salmon to their
ocean environment.