LAYTONVILLE, CA, 9/30/22 — Coho salmon have only been seen once in the Tenmile Creek watershed in the four years since the Eel River Recovery Project (ERRP) began monitoring there; but in mid-September, juvenile coho were observed in upper Cahto Creek, Mill Creek, and lower Little Case Creek, according to a news release Friday.
“Coho are basically the fishery species that helps indicate what the health of your watershed is,” Anna Halligan, North Coast project manager for Trout Unlimited, told The Voice in 2021. The salmon are protected under the Endangered Species Act and have faced significant challenges in our area due to changing climate conditions and habitat loss; the fish must have water colder than 62.4 F and prefer shaded streams with lots of big wood.
ERRP has been planning and implementing projects to restore salmon habitats in the watershed surrounding Laytonville since 2018. The group is currently utilizing a State Coastal Conservancy Proposition 1 grant to — among other water conservation projects — explore the interest of residents along western tributaries of Tenmile Creek, who are not included in the Laytonville County Water District’s Service area, in increasing water storage on their properties. The goal would be reduced withdrawal from streams or flow-affecting wells during the dry season.
“There is insufficient groundwater supply in the hills above the valley floor on the west side of Tenmile Creek, and residents often must withdraw water from creeks for their supply,” ERRP’s release explained.
The newly discovered presence of coho salmon is an added incentive for water conservation, making Upper Cahto Creek, Mill Creek, and lower Little Case Creek the priorities. ERRP explained that attempting to expand the water district’s service area would mean prohibitive energy costs and construction expenses in the tens of millions; as such, the group hopes to bundle applicants for augmented water storage and pursue large scale grants to both increase human water security and protect water availability for fish and wildlife populations. ERRP Outreach Coordinator Cheyenne Clarke has been reaching out to area residents to gauge their interest.
The group is also seeking forest health planning and implementation grants to help restore stream flow, as thinning forests lessens tree evapotranspiration.
Despite drought conditions impacting the entirety of Mendocino County, improved flows this summer compared with 2021 — California’s second driest water year — could have bolstered fish populations.
“[T]oday also marks the end of the 2022 [water year], which turned out better than the previous two years for fish due to timely rainfall,” ERRP Managing Director Patrick Higgins wrote in an email statement.
A breakdown of how the water year affected coho, from the ERRP press release:
Record rainfall in October 2021 and subsequent high flows through January 2022 allowed access all the way to headwaters for spawning coho. Egg survival was high because there were no subsequent major storms to wash out redds. Additionally, competition from steelhead was low because there was insufficient flow from January through March to allow adult access for spawning. Late March flows were extremely low and did not portend well for coho survival, but mid-April rains revived the flow enough to support them at some locations with surface flows in upper stream reaches maintained through most of summer. Flows began to disconnect after the early September heat wave, but then cool nights by mid-month signaled the change of seasons to trees that decreased water use enough for flows to be restored. This was further aided by early rainfall later in the month of approximately three inches. This leaves open the possibility of a strong year-class of Tenmile Creek coho, and a glimmer of hope for their potential recovery.
Find more information on ERRP initiatives here. Area landowners can find a time to meet with ERRP Outreach Coordinator Cheyenne Clarke at [email protected] or at (707) 223-7200. She will also be at the Laytonville Farmers Market the first three Mondays in October.