Three Year Report 2013-2015 Shasta and Scott River Juvenile Salmonid Outmigrant Study

Since 2000, the Anadromous Fisheries Resource Assessment and Monitoring Program (AFRAMP) conducted by the Yreka office of the California Department of Fish and Wildlife has operated rotary screw traps in the Scott and Shasta Rivers of the greater mid-Klamath River basin for the purpose of generating population estimates for out-migrating juvenile salmon. Described here are the results obtained during the 2013-2015 sampling seasons. Using rotary screw traps, all age classes of outmigrating Chinook salmon (Oncorhynchus tshawytscha), coho salmon (O. kisutch), and steelhead trout (O. mykiss), as well as a variety of native and non native fish species were sampled over these three years. Only Chinook and coho salmon data will be presented in this report. Using the Carlson method for mark and recapture of salmonids, trap efficiencies and population estimates were produced on a weekly basis. Established age-length cutoffs for each species were used to determine fish age. In-stream conditions such as flow and water temperature were also monitored. Weekly estimates for the smolt class of all species were compared to show multi-year population trends. Using multi-year seasonal production estimates and coho salmon returns to the Shasta River, adult survival and smolt production estimates were calculated for Shasta River coho. In 2013, it was estimated a total of 5,218,270 0+ Chinook, 1,930 0+ coho, and 494 1+ coho emigrated from the Shasta River during the sampling period. It was also estimated for the same sample period that 656,031 0+ Chinook, 1,290 0+ coho, and 7,927 1+ coho emigrated from the Scott River. In 2014, a total of 4,744,838 0+ Chinook, 10,752 0+ coho, and 850 1+ coho emigrated from the Shasta River. Additionally, 423,085 0+ Chinook, 760 1+ Chinook, 16,962 0+ coho, and 5,708 1+ coho, emigrated from the Scott River. It was estimated that for the period sampled in 2015, a total of 2,901,966 0+ Chinook, 851 0+ coho, and 6,279 1+ coho emigrated from the Shasta River.