Salmon Creek (Humboldt Bay) Spawning Survey Survey Jan 28-30, 2025

Salmonid Spawning Survey on Salmon Creek (Jan 28-30, 2025)

The PCFWWRA “Salmon Creek Instream Salmonid Habitat Improvement Design Project (South Humboldt Bay).”

Last January Pacific Watershed Associates conducted a three day salmonid spawning survey on Salmon Creek which runs into Humboldt Bay at Hookton Slough. The survey was a critical part of the PCFWWRA design project, “Salmon Creek Instream Salmonid Habitat Improvement Design Project (South Humboldt Bay).” That project will asses the in stream habitat conditions within a 2.8 mile reach on lower Salmon Creek and identify opportunities for in stream structure placement resulting in 100% designs for significant wood loading throughout the project reach benefitting all life stages for steelhead, Chinook, and coho salmon as well as coastal cutthroat trout.

The January spawning survey, led by Patrick Moorhouse of Pacific Watershed Associates, collected important data. The specific survey goal was to evaluate adult salmonid utilization below and above a waterfall that was created by a landslide in the spring of 2024. When the site was first visited after that landslide, the waterfall was 10’ high and was determined to be a barrier to migrating adult salmonids. Following very heavy November rains of almost 11 inches, the site was revisited on Dec. 6 by scientists and CDFW representatives. They found that the waterfall had head cut and migrated to a new location, approximately 50 feet upstream. Additionally, the waterfall was now only 4 feet tall, with a 3-foot deep jump pool immediately below it. Because the streambed material within the falls appeared to be wood and soil, the team speculated that the falls would likely continue to migrate upstream during the coming winter. Based on the measured height of the new falls and jump pool below, the CDFW no longer considered the falls to be a barrier to adult salmonids, but could still be a barrier for juvenile salmonids.

The CDFW recommended continuing monitoring efforts to “ensure escapement is maintained through the landslide and up into the greater Salmon Creek watershed.” The three day survey of Jan 28-30, 2025 was part of that monitoring effort. Live adult coho and steelhead were observed both above and below the landslide/waterfall. Multiple salmonid carcasses and redds were also documented above and below the slide area. Clearly, it was not a barrier for adult salmonids. After the survey, recommendations were made to the increase design project impoundment area moving forward. We're proceeding with the design project with input from our partners, the landowners (Green Diamond Resource Company) and the biologist from the California Department of Fish and Wildlife.