Central Valley Salmon – Priority Actions for Late Spring, Summer, and Fall 2025 by Tom Cannon
*Note: NCGASA is providing a place for more information on salmon, but all of Cannon’s recommendations do not necessarily represent the views of our organization. Salmon management is a complicated issue and NCGASA strives to provide all the information that is presented to share with our membership. We hope to educate everyone with additional data and recommendations so our members can get a full picture of the decline of our fisheries.
By Tom Cannon/ thomascannon0@gmail.com
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Water year 2025 is the third consecutive wet year after the 2020-2022 drought. In wet years emigrating juvenile natural-born and hatchery salmon (winter, spring, and fall run) and immigrating adult natural-born and hatchery salmon (late fall, winter, spring, and fall run) gain survival advantage from good habitat conditions in late spring, summer, and fall in the Bay-Delta and Central Valley, especially in the lower Sacramento River and its tributaries (Maps 1 and 2). Hatchery smolts released to rivers, the Bay-Delta, and the coastal ocean benefit substantially from trucking in wet years as they do in dry years. Salmon brood-year recruitment is heavily dependent on the good survival and reproduction conditions provided in wet years. High brood year recruitment is critically important to populations presently near record low levels after three multiyear droughts in the past two decades. The future of salmon public trust resources depends on wet water years like 2025. Water year 2025 is of particular importance because salmon numbers are at or near their lowest levels in many decades despite recent fishery closures.
The future success of salmon brood 2024 and 2025 is dependent on good habitat conditions from spring to fall in wet year 2025. Brood years 2024 and 2025 success is especially important given they are the first offspring from the 2020-2022 drought-produced broods that have had good water conditions for them and their parents (in water years 2023 and 2024). Future population health and growth is thus highly dependent on providing good habitat conditions in 2025. With 2025 being a wet year, the necessary water resources are available for good habitat conditions.
With Sacramento River and Bay-Delta flows near optimal for salmon in winter-spring of wet years 2023 and 2024, and now again in 2025 the odds of salmon recovery in the coming years are good. Winter-spring 2023 near-optimal conditions should have provided a strong fall-run spawning stock for 2025 as long as good late summer and fall river conditions are maintained. Natural and hatchery smolt production and survival to the ocean in late spring 2025 should be good with good spring late spring habitat conditions. Good habitat conditions include strong river flows and lower water temperatures at least through June as well as in late summer and fall.
Decades of review and analyses of Central Valley winter-spring water conditions indicate there is a flow regime that is near optimal for winter, spring, and fall-run salmon annual production. Maintaining an optimal flow and water temperature regime in 2025 will maximize survival and smolt production of winter, spring, and fall run salmon in the Central Valley, and contribute substantially toward Central Valley salmon recovery. With three wet years in a row and full reservoirs providing an optimal regime beginning in late spring, late summer, and fall to maximize survival of natural-born and hatchery brood year 2024 salmon smolts to the ocean and optimize survival and spawning success of brood year 2025 parents.
Tom Cannon is an estuarine fisheries ecologist and biostatistician and has been involved in Delta fishery issues for more than 35 years. Over that period, Tom has worked for or been a consultant to the California Department of Fish and Wildlife, U.S. Bureau of Reclamation, National Marine Fisheries Service, State Water Contractors, CalFed Bay-Delta Program, State Water Resources Control Board, PG&E, California Striped Bass Association, Fisheries Foundation and CSPA. He has been involved in numerous habitat restoration projects. Find his reports on https://calsport.org/fisheriesblog/
