Most of California’s salmon and trout could be gone in coming century if not saved now, study says
Salmon are at the heart of tribal cultures up and down the West Coast—their diet, commerce, ceremonies, and spirituality. They appear in cave art of 10,000 or more years ago. Salmon are not just a way of life. They are life.
And in California, they may soon be extinct.
Three quarters of the state’s salmonids, as salmon and trout are called, could be gone in a century if conditions don’t change. That’s according to a new scientific assessment released on May 16. Nearly half of all salmon species face extinction in 50 years if trends in the state stay the same.
The report, State of the Salmonids II: Fish in Hot Water, from the UC Davis Center for Watershed Sciences, and CalTrout, a nonprofit organization, is updated from a study done a decade ago to reflect the latest climate models, and other factors including the five-year drought, which in addition to other stressors pushed several species to the edge of extinction.
“Overall, California’s salmonids are markedly worse off than in 2008,” said lead author Peter Moyle, professor emeritus in the Department of Wildlife, Fish and Conservation Biology and Associate Director of the Center for Watershed Sciences at UC Davis, during a media teleconference May 16. “The impacts of climate change have become much clearer than in the past.”
The team’s updated analysis found that climatic impacts are the single largest threat to salmonid survival for several reasons. Salmon, steelhead, and trout need clean, cold water to survive. Rising temperatures will reduce critical snowmelt, and decrease stream flows.
For migratory species like salmon that move between ocean and freshwater systems from the state’s northern border with Oregon to its southern border with Mexico, the threat of climate change is followed by threats caused by estuary alterations from developments on shorelines, major dams and agriculture. Inland species like trout face other threats, such as invasive fish species.
At the same time, the researchers point to salmonids’ resilience in surviving the five-year drought. And they say that salmon, steelhead and trout have adapted to a wide variety of climatic conditions in the past, and could likely survive substantial changes to climate if other stressors and threats were reduced. The report recommends protecting strongholds, or the best habitat remaining, as well as protecting and restoring source waters, and productive and diverse habitats, among other actions such as supporting wild fish in working landscapes.
The researchers reviewed the scientific literature and interviewed fisheries experts to determine extinction risk. The report has recommendations for each of the 32 salmonid species in California. Each was scored a Level of Concern, with zero being extinct, one critical, up to five being a low level of concern.
The Yurok, Karuk, Hoopa, and Klamath tribes fish in the Klamath River that divides Oregon and California. In the new report, spring run Chinook salmon in the Klamath Basin scored critical at 1.6. Four dams on the Klamath River keep this run from their traditional spawning grounds.
Spring Chinook salmon were historically the largest run in the upper Klamath Basin before the dams were built, the Karuk Tribe’s Natural Resources Policy Advocate Craig Tucker told ICMN.
“This is a case adamant for removing the dams,” said Tucker, a scientist who was not a part of this study. “There is cold-water habitat upstream of the dams. Spring run Chinook salmon spend their summers in river, and is one reason dam removal is so important.”
“The only solution for the long-term survival of our salmon is providing access to cold water by removing the dams that are blocking the salmon,” said Toz Soto, a fisheries biologist and the Fisheries Program Manager for the Karuk Tribe, to ICMN. “The tributaries above the dams are spring fed [they continually produce cold water], and so are not affected by climate warming like rain or snow-fed rivers. It’s also a stable source of water. I’m very excited about dam removal because it opens up a whole network of spring-fed rivers.”
“For the Yurok people, whose culture and livelihoods are inextricably linked to the Klamath salmon, improving fish runs means everything,” said Amy Cordalis, the Yurok Tribe’s General Counsel, and a salmon fisher, to ICMN. “We are pleased that PacifiCorp’s 2020 dam removal deadline is on schedule. Dam removal, along with targeted habitat restoration, will help restore salmon populations in the Klamath Basin. Thermal refuge areas need to be created and protected at strategic locations throughout the basin, as recommended in this new report for salmonid resilience and survival in a changing climate.”
The scientific assessments of the Klamath River by the tribal biologists and scientists match those of the reports’ authors, which is primarily to remove the four lowermost dams and access the spring-fed cold water above the dams, and keep the cold water in the streams.