SS1.05 How Will Aquatic Ecosystems Respond to Climate Change?
Date: Tuesday, June 11, 2002
Time: 11:00:00 AM
Location: Oak Bay
 
WelchDW, Pacific Biological Station, Nanaimo, Canada, welchd@pac.dfo-mpo.gc.ca
Trudel, M, , Pacific Biological Station, Nanaimo, Canada, trudelm@pac.dfo-mpo.gc.ca
Zamon, J, , Pacific Biological Station, Nanaimo, Canada, zamonj@pac.dfo-mpo.gc.ca
 
LATITUDINAL AND TEMPORAL GRADIENTS IN OCEAN PRODUCTIVITY & SURVIVAL OF SALMON
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Systematic differences in marine survival of Pacific salmon are evident for different regions of the West Coast of North America. Off Washington and Oregon, coho survival dropped from 6% in the 1960s to only 0.6% by the 1990s– a ten-fold decrease. The same trend is seen for southern BC coho, where the decline was from 20-25% to 2-3% survival. However, SE Alaskan coho survival remained consistently high at 20-25% over the same period. Average survivals and temporal trends are therefore region-specific. We initiated a field survey to examine ocean growth and survival, and show that southern regions of the West Coast had poor growth and expected survival until 1999. It appears that stocks with poor observed survival migrate to the region of poor expected survival, while stocks in good condition migrate farther north to regions of higher expected survival. A simple linear relationship with changes in the food chain was not seen. A critical need is to directly establish where specific stocks of salmon go in the ocean, so that the effects of ocean climate changes can be examined directly.