SS3.21 Deconstructing Rivers: The Ecological, Geomorphic, and Social Consequences of Dam Removal
Date: Thursday, June 13, 2002
Time: 12:00:00 PM
Location: Colwood
 
HoekstraJM, National Marine Fisheries Service, Northwest Fisheries Science Center, Seattle, USA, Jonathan.Hoekstra@noaa.gov
Ruckelshaus, M, , NMFS Northwest Fisheries Science Center, Seattle, USA, 
Harms, T, , NMFS Northwest Fisheries Science Center, Seattle, USA, 
Piasecke, J, , NMFS Northwest Fisheries Science Center, Seattle, USA, 
Johnson, J, , NMFS Northwest Fisheries Science Center, Seattle, USA, 
 
DAMMED IF WE DO OR DAMMED IF WE DONT? ASSESSING THE RELATIVE IMPACT OF DAMS, HABITAT, HATCHERIES AND HARVEST ON PACIFIC SALMON.
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Among the most contentious debates concerning recovery of endangered Pacific salmon in the Pacific Northwest, USA, is that regarding removal of hydroelectric dams. Proponents of dam removal argue that salmon populations will benefit by restoration of natural river flows and elimination of passage obstructions. Opponents counter that structural and operational modifications have mitigated adverse effects of dams, and that recovery will depend on habitat restoration and reformation of hatchery production and harvest policies. Both arguments are true all four Hs (Hydroelectric dams, Habitat quality, Hatchery production, and Harvest) have contributed to declines of Pacific salmon stocks and must be addressed if we are to recover these populations. However, we are only beginning to understand combinatorial effects of the four Hs, and to quantify their relative impacts. I will present results of a regional-scale multivariate analysis designed to estimate effects of all four Hs on salmon population growth rates (lambda) across the Pacific Northwest. Generalizations drawn from this All-H analysis will provide insights into the likely effectiveness of alternative recovery actions, including dam removal, within the context of other Hs.