Stine Griep¹, Carlos Polivka², Keith Van Den Broek¹, David Glisson¹, Virginia White¹

1. Hinchinbrook Inc., 2030 Sleepy Hollow Hts, Wenatchee, WA 98801
2. Pacific Northwest Research Station, USDA, 1133 N Western Ave, Wenatchee, WA 98801

To restore riverine habitat for Pacific Northwest salmonids, Engineered Log Jams (ELJs) are frequently utilized, though studies of their specific impact on salmon populations show mixed results. We conducted an investigation of fish abundance and behavior in the Entiat River, WA, a model system for salmon restoration with a history of ELJ implementation.

Our study centered on PIT tagging and recapturing juvenile Chinook salmon and steelhead within various ELJs in three river reaches and associated untreated reaches. We sought to understand their temporal habitat utilization patterns and movement between ELJ-treated habitat units. We also employed a PIT tag antenna array within a large ELJ to decipher utilization dynamics within such habitats.

High recapture rates suggest that salmonids are associated with ELJs in large numbers during the summer, with ongoing recaptures planned for the fall and winter to ascertain outmigration timing. Additionally, our findings indicate robust detection rates within ELJs, offering insights into salmonid cohabitation and potential temporal behavioral shifts.

This study contributes to a deeper understanding of salmonid utilization and movement within ELJs, shedding light on their role in salmon habitat conservation.