Shasta and Scott River Salmonid Outmigrant Monitoring

One rotary screw trap (RST) was operated on the Shasta River from mid-January to the beginning of June in 2022 and end of January to mid-July in 2023. One rotary screw trap was operated on the Scott River from the beginning of February to the end of June in 2021. In 2022, two rotary screw traps were operated on the Scott River from the end of January to the end of June. The RSTs were used to sample all age classes of emigrating Chinook Salmon (Oncorhynchus tshawytscha), Coho Salmon (Oncorhynchus kisutch), and steelhead trout (Oncorhynchus mykiss). For the period sampled in 2023, statistical analyses are in progress due to application of Bayesian statistical methods to address application of reduced sampling effort to 5 days per week.

In 2005, Coho Salmon of the Southern Oregon/Northern California Coast Evolutionary Significant Unit were listed as a threatened species from the Oregon border to Punta Gorda, California under the California Endangered Species Act. The data collected from the RSTs on both the Scott and Shasta River represent one of the only long-term monitoring datasets for Coho Salmon populations and other target species, which can be used to evaluate the effectiveness of restoration projects that are intended to increase juvenile salmonid production and survival. Additionally, evaluating abundance, timing, and fork length of the outmigration salmonids, provides indications to habitat conditions and distribution.