Skip to main content
U.S. flag

An official website of the United States government

Snake River fall Chinook salmon life history investigations, 1/1/2013 – 12/31/2013

March 11, 2015

Smallmouth bass predation on subyearling fall Chinook salmon was examined in the upper portion of Lower Granite Reservoir during 2013. During the time subyearlings were present in the reservoir, smallmouth bass were collected, their stomach contents removed for diet analysis, and their abundance estimated with mark-recapture techniques. In 2013, the greatest consumption of subyearlings by smallmouth bass occurred in late May and early June—as much as 50% of their diet by weight. Sand rollers were the most common non-salmonid fish consumed by smallmouth bass. In the section of the reservoir above the confluence with the Clearwater River, the abundance of bass was higher in non-riprap habitat than in riprap, but the opposite was true in the section below the confluence. We estimated that over 168,000 subyearlings were lost to smallmouth bass predation in 2013. Given the predominance of sand rollers in the diet of smallmouth bass, we believe this species reduces predation on subyearling fall Chinook salmon. A complete report of our findings is provided in the Appendix.

Publication Year 2015
Title Snake River fall Chinook salmon life history investigations, 1/1/2013 – 12/31/2013
Authors Kenneth F. Tiffan, William P. Connor
Publication Type Report
Publication Subtype Other Government Series
Index ID 70148621
Record Source USGS Publications Warehouse
USGS Organization Western Fisheries Research Center
Was this page helpful?