Shasta and Scott River Salmonid Outmigrant Monitoring FY24/25

One rotary screw trap (RST) was operated on the Shasta River from end of January to the mid-June in 2024 and 2025. For the period sampled in 2024, we estimated that a total of 4,750,230 age 0+ Chinook Salmon; 4,090 age 0+ and 935 age 1+ Coho Salmon; and 6,234 age 0+, 5,495 age 1+, and 117,207 age 2+ steelhead trout emigrated from the Shasta River. One rotary screw trap was operated on the Scott River from mid-February to mid-June in 2024. In 2025 one rotary screw trap was operated on the Scott River from mid-February to mid-July. For the period sampled in 2024, an estimated 334,626 age 0+ Chinook Salmon; 1,142 age 0+ and 10,202 age 1+ Coho Salmon; and 404,071 age 0+, 126,366 age 1+, 16,873 and age 2+ steelhead trout emigrated from the Scott River.

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. Drought conditions from 2020-2023 have resulted in critically dry and emergency situations for local salmon that require an expanded juvenile monitoring effort. Monitoring juvenile coho and their summer habitat will expand our baseline habitat use information, help inform Voluntary Drought Initiative agreements, and support any required law enforcement effort.