Operation of rotary screw traps on the Lower American River is part of a collaborative effort by the U.S. Fish and Wildlife Service’s Comprehensive Assessment and Monitoring Program, Pacific States Marine Fisheries Commission, and the California Department of Fish and Wildlife. The primary objectives of the study are to collect data that can be used to estimate the passage of juvenile fall-run Chinook Salmon (Oncorhynchus tshawytscha) and to quantify the raw catch of steelhead (Oncorhynchus mykiss) as well as winter, spring, and late fall run Chinook Salmon. Secondary objectives of the trapping operations focus on collecting fork length and weight data for juvenile salmonids and gathering environmental data that will eventually be used to develop models that correlate environmental parameters with salmonid size, temporal presence, abundance, and production.
North Channel Rotary Screw Traps - Courtesy of Douglas Threloff