Sea Lion Monitoring and Hazing in the Lower Columbia River

The intent and focus of this project is to address marine mammal predation on Columbia River salmonids.  This is a new and growing impact to salmonids particularly in the last several years. To date, most of the attention has focused on the area just below Bonneville Dam, where salmon are concentrated before they enter the fish ladders and where visual estimates of predation rates are easier to develop. However, there are anecdotal reports of extensive sea lion predation in areas below the dam that are not visible from the dam. This unaccounted predation may be greater than the observed predation.

The objectives of the project are:

• Objective 1.  Estimate sea lion abundance in the lower Columbia beyond the view of observers stationed at Bonneville Dam.
• Objective 2. Track movements of individual sea lions at various spatial scales in the Columbia River using GPS cell phone tags.
• Objective 3.  Conduct boat-based non-lethal sea lion hazing annually generally between March 1 and May 31 in the Bonneville Dam tailrace.

Each of these objectives is required under the Hydro system Biological Opinion Reasonable and Prudent Actions (RPA) 49 and 69.