Wednesday, January 13, 2010

Avian Predator Mitigation Efforts Paying off on the Columbia

Grant County PUD scientists say efforts to reduce predation by avian predators such as caspian terns and gulls at Wanapum and Priest Rapids dam appear to be working to some extent. The predatory birds normally congregate near the spill ways of dams where disoriented juvenile fish are passed from the reservoir above. This year predator hazing efforts began earlier and lasted later in the migration period and a new wire array downstream of the spill way was installed in 2008 designed to reduce the predation pressure on migrating juvenile salmonids. This year survival of both steelhead and sockeye outmigrants was over 95% a dramatic improvement over last year when only 91% of steelhead and roughly 85% of sockeye survived passage through each dam. More information in the Columbia Basin Bulletin:

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