Predation Challenges Faced By Columbia River Salmon 1 October 4, 2013 Columbia River Inter-Tribal Fish Commission
The Big Four Caspian Tern Double-crested Cormorant Northen Pikeminnow California Sea Lion Columbia River Inter-Tribal Fish Commission
Avian Predation Caspian Tern Double-crested Cormorant Birds consumed an estimated 24.3 million migrating juvenile chinook and steelhead in 2010, which represents 228,000 returning adults Columbia River Inter-Tribal Fish Commission
Aquatic Predation Northen Pikeminnow Predator fish consume an estimated 12 million migrating juvenile chinook and steelhead, which represents 38,000 returning adults Columbia River Inter-Tribal Fish Commission
Pinniped Predation California Sea Lion Pinnipeds consume an estimated 18,000 returning adult chinook and steelhead Columbia River Inter-Tribal Fish Commission
Sea Lion Impact 4.2% predation rate is only from observations within 400 yards of Bonneville Dam Sea lions roam throughout the 146 miles of the lower Columbia River, where they have an estimated 18% Columbia River Inter-Tribal Fish Commission predation rate
Pinniped Impacts Columbia River Inter-Tribal Fish Commission
California Sea Lions in Bonneville Pool At least 4 California sea lions currently reside in the Bonneville pool. At least one animal has been there for more than 3 years. These animals impact all stocks that originate upstream of Bonneville Dam including some of the weakest stocks like winter steelhead. 8 Columbia River Inter-Tribal Fish Commission
California Sea Lions in Bonneville Pool Sea lions below the Bonneville Dam tailrace generally leave within two months. Sea lions residing in the Bonneville pool impacting stocks year-round, making their individual impacts about 6 times greater than sea lions that can leave the system. The impacts from the 4 sea lions in the Bonneville pool may be similar to 25 animals in the tailrace. Removing these animals needs to be a priority. 9 Columbia River Inter-Tribal Fish Commission
California Sea Lions in Bonneville Pool These animals impact tribal fishers by damaging gear and catch. This is a particular problem at the beginning of the season during ceremonial fishing, when total fish numbers are very low. 10 Columbia River Inter-Tribal Fish Commission
Other Predator Species on the Rise Smallmouth Bass Smallmouth Bass consume about 7,000 juvenile salmon a day in the Yakima River. 98% are subyearling chinook; 70% are natural-origin Steller Sea Lion abundance at Bonneville Dam 2008: 17 2009: 26 2010: 53 Steller 2011-2013: >70 Sea Lions Columbia River Inter-Tribal Fish Commission Listed under MMPA and ESA
Non-native Fish a Growing Problem Largemouth Bass Walleye Catfish Columbia River Inter-Tribal Fish Commission
Columbia River Inter-Tribal Fish Commission
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