Earlier this year, our senior fellow Jeff Mount and UC Davis’s Carson Jeffres explained that three “wettish” years in a row offered a crucial opportunity for salmon to recover from the 2020–22 drought. We sat down with them this month to get an update.
So, catch us up. How did things pan out?
Jeff: Before Carson gives his assessment, I should stress how unusual these past three years have been. If you look at the parts of the state that produce most of our salmon—the Sacramento River and North Coast hydrologic regions—you had three consecutive average- to above-average years of precipitation. The last time that happened was in the late 1990s, more than 25 years ago. And before that, it happened in the early ‘80s. Usually, a dry year or multiple dry years separate wet years in California.
Carson: These three wettish years followed three record dry and warm years, and that’s a big deal. In 2022—during the third year of drought—very few adults made it back to successfully spawn. The juveniles from this small cohort benefitted from a wet winter/spring in 2023, though. High flows gave them access to good habitat and helped carry them to the ocean. These salmon have made their way home this year and, considering how few salmon successfully spawned, the numbers are a pleasant surprise.
We won’t know full totals until sometime next year when all the data are in, but the initial reports are good. We saw very strong returns of coho salmon on the North Coast last winter, but it’s too early to tell for this year. Fall-run Chinook are showing up in large numbers in the Sacramento River and its tributaries, and two of our most challenged salmon runs—winter-run and spring-run Chinook—have shown up in modest numbers. These fish are teetering on the edge of extinction, so it’s great to see them make it home.
So, what did we learn from these numbers of returning salmon?
Carson: Salmon are inherently a boom-and-bust species. They take advantage of good times like these wettish years to build their population numbers. Large wet-year populations build resiliency for the inevitable dry years, when spawning success will be low. Our salmon are in trouble for many reasons, but basically we need to do more to boost their populations in wet years and in turn help them survive the bad years so they can prosper when the wet years return.
Jeff: California is doing a lot to bolster salmon numbers. Some of the spectacular returns of coho salmon on the North Coast are due to major investments by the state and nonprofits in improving spawning and rearing habitat. This year the state celebrated the Big Notch Project—a notch in the Fremont Weir along the Sacramento River that connects the river to high-value floodplain habitat on the Yolo Bypass. And of course, the removal of the Klamath dams has been much in the news as salmon are now appearing in parts of the watershed that were blocked for more than a century. We need to remember to celebrate successes whenever we can.
Final thoughts?
Carson: We must do things that let salmon be salmon, taking advantage of the thousands of years of evolution that make them able to respond to California’s variable climate.
Jeff: All the great work to protect salmon today depends upon the outstanding science of so many who came before us. One name deserves special mention: Peter Moyle of UC Davis.
So much freshwater fish conservation and ecosystem restoration in California traces its origins back to Peter’s 60 years of outstanding research. Carson and I have both had the good fortune of working with Peter, and he’s worked with the PPIC team for several decades and has coauthored many PPIC reports. His insights on ecosystem management have been foundational to many Water Policy Center recommendations over the years.
To honor Peter’s legacy of great science, and to turn his many good ideas into good policy, the PPIC Water Policy Center has established the Peter B. Moyle Fund for Environmental Water Policy. Keep an eye out for exciting new initiatives starting next year.
