Drop in West Coast sockeye salmon productivity
Randall Peterman, 778.782.4683; firstname.lastname@example.org
Don MacLachlan, PAMR, 778.782.3929; email@example.com
A new study by Simon Fraser University fisheries scientists has found a widespread decrease in the number of adult sockeye salmon produced per spawner for at least the past decade along the western coast of North America.
Published today in the Canadian Journal of Fisheries and Aquatic Sciences, and co- authored by Randall Peterman, a professor in SFU’s School of Resource and Environmental Management and former post-doctoral fellow Brigitte Dorner, the study traces the productivity of 64 sockeye salmon populations across B.C., Washington and Alaska.
“It is possible that the downward trends in productivity across the sockeye stocks of Washington, B.C. and southeast Alaska result from a variety of causes, such as freshwater habitat degradation or contaminants, that have each independently affected many small regions,” says Randall Peterman.
“However, the large spatial extent of similar time trends in productivity for 24 of those stocks has occurred in both relatively pristine and heavily disturbed habitats. This suggests that shared mechanisms are a more likely explanation -- for example, high mortality owing to predators, pathogens, or poor food supply that occur across these areas.”
Researchers found that the decline in productivity of Fraser River sockeye salmon was not unique to that river system, and that productivity has also declined rapidly in many other populations since the 1990s.
The trend of decreasing productivity has also spread further north over the past two decades – consistent with large-scale changes in climate-driven oceanographic patterns known to affect sockeye productivity.
The findings have important implications for salmon stock management and Peterman says further research on the potential causes will help determine future management strategies.
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