Zeroing In On Spawner Surveys

Lower Redwood Creek Lagoon. Despite being full of water, one or two more storms are needed to blast through a sand bar on Muir beach and allow for fish passage. NPS / Michael Reichmuth

December 2020 - As we approach winter, coho salmon and steelhead trout are getting ready to begin spawning. Just before Thanksgiving, the fisheries crew with the San Francisco Bay Area Network Coho & Steelhead Monitoring Program conducted “Zero Count Surveys” along the lower sections of Redwood and Olema Creek. Zero counts are spawner surveys that occur before winter flows permit fish passage throughout a creek. In these initial observations, the number of redds and salmonids is expected to be zero. These surveys enable the fisheries crew to search for any signs of early fish passage before large storm events scour that evidence away. Surveying these creek sections allow the fisheries crew to observe stream channel connectivity and barriers to fish passage. Additionally, these zero counts serve as a training opportunity, allowing the team’s new members, Dustin Geisen and Samantha Kuglen, to gain valuable experience as surveyors.

A downed willow resprouts roots while adrift in Redwood Creek. Woody debris such as this provides crucial cover for salmonids and while also serving as additional nutrient input for the creek. NPS / Michael Reichmuth

Currently, the fisheries crew is waiting for more rain to increase creek flow and commence spawning season. Winter spawner surveys help to provide a measure of the overall spawning success and run size of each returning cohort of salmon. In turn, this monitoring helps determine long-term trends in distribution and abundance of coho salmon in Olema, Redwood, and Pine Gulch Creeks. Fingers crossed for more rain to get this year started!

See more from the San Francisco Bay Area Coho and Steelhead Blog and Bay Area Nature & Science Blog

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