Predation Challenges Faced By Columbia River Salmon 1 October 4, - - PowerPoint PPT Presentation

Columbia River Inter-Tribal Fish Commission 1

Predation Challenges Faced By Columbia River Salmon

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

• bservations

within 400 yards

• f Bonneville

Dam Sea lions roam throughout the 146 miles of the lower Columbia River, where they have an estimated 18% predation rate

Columbia River Inter-Tribal Fish Commission

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

• f the weakest stocks like winter

steelhead.

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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.

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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.

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Columbia River Inter-Tribal Fish Commission

Other Predator Species on the Rise

Smallmouth Bass consume about 7,000 juvenile salmon a day in the Yakima River. 98% are subyearling chinook; 70% are natural-origin

Smallmouth Bass Steller Sea Lions

Steller Sea Lion abundance at Bonneville Dam 2008: 17 2009: 26 2010: 53 2011-2013: >70 Listed under MMPA and ESA

Columbia River Inter-Tribal Fish Commission

Non-native Fish a Growing Problem

Largemouth Bass Walleye Catfish

Columbia River Inter-Tribal Fish Commission