Friday January 20, 2023
CalTrout —
As drought persists and future impacts of climate change threaten, salmonids across the state will increasingly seek out refuge from warming waters. Cold-water streams like Big Mill Creek, a tributary to the East Fork of the Scott River, offer important refuge for these fish including the federal and state threatened coho salmon. In the next few years, CalTrout, with the support of The Wildlands Conservancy and our project partners, will prepare to implement a project to restore fish access to upstream habitat in Big Mill Creek creating impacts that could ripple throughout the whole watershed.
“The East Fork represents an opportunity to increase resilience in the Scott River,” Mt. Shasta/Klamath Region Project Manager Serena Doose explained. Much of the river is warm, but there are cold-water pockets where thousands of coho salmon can be found. “There’s a lot of potential there.”
Coho salmon require a full year of residence in freshwater after emerging from the gravel in the spring. Summer residence is a difficult feat in the Scott River, when the mainstem river often disconnects and large patches of the river and its tributaries go dry. However, Big Mill Creek is a perennial tributary, meaning that it flows year-round, even in the recently dry years. Summer temperatures in the creek hover between 50-60 degrees Fahrenheit, representing a critical refuge for coho when the mainstem can reach 70-80 degrees Fahrenheit. In drought conditions, this thermal refugia is a key link to saving salmon populations and offers important ecological resilience to impacts of climate change.