Large wood restoration effectiveness for salmonids in Pudding Creek, California: A before-after-control-impact experiment
August 2018 - June 2021
- California Department of Fisheries and Wildlife
The object of this project is to evaluate the growth and survival response of endangered Central California Coast Coho Salmon (Oncorhynchus kisutch) and threatened Northern California steelhead (Oncorhynchus mykiss) to large woody debris (LWD) treatments on Pudding Creek in Fort Bragg, California using a before-after-control-impact design. This analysis comes from data collected in a Before-After-Control-Impact (BACI) study initiated in 2012 based on monitoring salmon populations on both Caspar and Pudding creeks. In 2015, LWD was strategically placed in 80% of mainstem Pudding Creek while Caspar Creek was the untreated control. The standardized mean abundance estimates of Coho Salmon parr captured in outmigrant traps followed a similar trend in both creeks, suggesting the creeks work well as paired watersheds for the BACI design. A growth analysis using summer and fall electrofishing data found that steelhead have not been greatly impacted by wood treatment while Coho Salmon growth per day (mm•d-1) after treatment was significantly higher in Pudding Creek than Caspar Creek. Billions of dollars have been spent on watershed restoration in California in recent decades, yet relatively few studies have linked habitat improvements with any effects on fish survival, growth, or abundance. This study will quantitatively measure the effect of large woody debris supplementation on the survival, growth, and abundance of Coho salmon and Steelhead trout so that managers can make informed decisions on how to most efficiently spend the limited amount of restoration funds available.