Cooperative Fish and Wildlife Research Units Program: California
Education, Research and Technical Assistance for Managing Our Natural Resources

This project will use a DIDSON sonar imaging system to estimate the number of adult steelhead migrating into and out of Redwood Creek during the 2015/2016 spawning season, to provide status and trend information for this ESA-listed fish. A DIDSON has been deployed on Redwood Creek since 2009 to test its potential for monitoring escapement of adult salmon. Previous research has demonstrated that analysis of images captured by DIDSON can be used effectively to enumerate migrating salmonids over a wide range of conditions. When combined with existing smolt monitoring data, these data will alllow smolt to adult and adult to smolt survival to be estimated. The project will also describe migration timing of steelhead in Redwood Creek, and evaluate relationships with environmental conditions (streamflow, temperature, tides) using standard statistical techniques.