First Advisor

Deborah Duffield

Date of Award


Document Type


Degree Name

Bachelor of Science (B.S.) in Biology and University Honors




Pinnipedia -- Control -- Pacific northwest, Predatory marine animals -- Behavior -- Pacific northwest, California sea lion, Steller's sea lion, Bonneville Dam (Or. and Wash.), Oregon. Department of Fish and Wildlife, United States. Army. Corps of Engineers




Both Zalophus californianus and Eumetopias jubatus are species known to travel upriver into the Columbia River, reaching as far as the Bonneville Lock and Dam. Bonneville Dam works with federal agencies to hatch and protect salmonids within the Columbia River. Pinnipeds at the dam have been studied since the 1980's in an effort to understand their behaviors and feeding patterns on endangered salmon species. Since 2006, the hazing of Z. californianus and E. jubatus has gone on, showing little effectiveness in lowering the sea lion's consumption rates (ranging from 0.4-5.8% annually). Behavioral analyses conducted during the spring salmon run of 2019 produced no visible sightings of salmon consumption, but showed large utilization of fire arms and boat chasing to deter sea lions from the dam area. While behavioral analysis data was limited, this data in conjunction with literature suggests that the programs run by the Oregon Department of Fish and Wildlife (ODFW) and the US Army Corps of Engineers (USACE) are unsuccessful in deterring sea lions from Bonneville Dam and should be reevaluated.


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