Yuba River Fall-Run Salmon Crash 2016-2025

Posted on March 24, 2026 by Tom Cannon

The Yuba River Fall-Run Chinook salmon population “crashed” in the last decade. Yuba River escapement ranged only from 2000-5000 spawners counted per year (Figure 1). Such low escapements were last encountered only during the Central-Valley-wide crash during the 2007-2009 drought.

The decade-long low escapement reflects the effects of two droughts (2013-15 and 2020-22). Though the 2023-to-2025 escapements have increased slightly¹ despite the 2020-2022 drought, the higher escapement reflects the benefit of fishery closures from 2023-2025 (fisheries normally harvest more than 50% of the adult stock). Yuba escapement also reflects substantial numbers of hatchery strays from other rivers, including the Mokelumne and American River hatcheries, the Coleman hatchery on Battle Creek in some years, as well as the Feather River (Oroville) hatchery. Small numbers of spring-run Feather hatchery strays from release locations near the mouth of the Yuba on the Feather River are also included.

The highest number of strays in the 2020-2022 period were from one group of Mokelumne River hatchery smolts released in 2018 to Half Moon Bay on the coast south of San Francisco. The next highest group of strays are from American and Feather hatchery smolt releases to San Francisco Bay. The trucked hatchery smolts do very well during drought years and thus tend to bias high the Yuba returns from drought years. That is to say, drought effects on the natural Yuba run are even worse than indicated in escapement estimates.

I categorize the decade-long decline as a “crash” based on the population spawner-recruit (S/R) relationship (Figure 2). The S/R “curve” generally reflects a positive logarithmic relationship between spawner and recruitment numbers. The more eggs spawned generally leads to more adult returns three years later. The S/R ratio, at least in the Central Valley salmon populations, also reflects drought or habitat conditions wherein recruits are generally depressed from density-independent habitat factors like droughts. The six drought years in the last decade shown in Figure 2 as red dots have led to escapement levels in the lower-left quadrant of the S/R curve – a pattern often referred to as a population crash.

Often it is difficult for a population to recover from that situation because there are not enough spawners (eggs) to get the population out of the hole. It would take a lot of good years in sequence to make that happen, unless certain actions are taken to accelerate the recovery. For some suggestions on how this can be accomplished, see my past post on the subject.

Because of the supplementation of recruitment from other rivers and resulting mixed bag of spawners, the Yuba run is not threatened with extinction. However, in its present state, its poor contribution to the commercial and recreational fisheries is a problem. The Yuba is a magnificent salmon river that should contribute more salmon.

Figure 1. Yuba River Fall-Run Chinook salmon escapement estimates 1953-2024.

Figure 2. Yuba River Fall-Run Chinook salmon spawner-recruitment relationship wherein recruits are related to recruits three years earlier. Red dots represent escapement years where two years earlier it was a drought year during rearing and outmigration.

The preliminary 2025 estimate is near 6000, https://yubariver.org/posts/yuba-river-salmon-return-numbers-september-december-2025/ ↩

Sacramento River Salmon Redd Dewatering – Fall 2025

Posted on December 29, 2025 by Tom Cannon

I have previously reported on the dewatering of fall-run salmon redds in the upper Sacramento River near Redding during the early fall spawning season. Redd dewatering has a significant negative effect on salmon egg and fry production that translates to lower annual escapement and significantly contributes to the multi-decade decline in the population (Figure 1).

Figure 1. Escapement to the upper Sacramento River natural spawning area 1952-2024.

October is the peak in the fall-run Chinook salmon spawning season (Figure 2). During early November 2024, the Bureau of Reclamation reduced Keswick Dam releases from the October average of 7000 cfs to 4000 cfs. The flow reduction reduced water levels in the upper river spawning grounds below Keswick Dam from approximately the 11-ft water surface elevation (stage) to about the 8.5 ft level, a drop of about 2.5 feet. In 2025, nearly identical flow management led to the same redd dewatering conditions (Figure 3). With most of salmon redds constructed in the 1-to-3 ft depth range, most were dewatered or only slightly watered and thus susceptible to high-egg-mortality conditions (low flow, warm water, low oxygen, and sedimentation).

The flow management strategy was also employed in recent wet years 2017 and 2019, although a more benign strategy was employed in historical wet year 2011 (Figure 4). The issue has attracted inter-agency study and mention, but actions necessary to reduce the problem have been limited.

Figure 2. Stage and water temperature in the Sacramento River below Keswick Dam in fall 2024. Grey box denotes period when most fall run salmon spawn in the upper Sacramento River.

Figure 3. Stage and water temperature in the Sacramento River below Keswick Dam in fall 2025. Grey box denotes period when most fall run salmon spawn in the upper Sacramento River.

Figure 4. Stage and water temperature in the Sacramento River below Keswick Dam in fall of wet years 2011, 2017, and 2019.

American River Salmon Update – Spawning Season, November 2025

Posted on December 10, 2025 by Tom Cannon

In a 10/19/2023 post and a 11/21/2024 post, I discussed how the lack of access to Folsom Reservoir’s deep cold-water pool results in delayed natural and hatchery spawning of American River fall-run salmon. Delays, and spawning in warmer water, cause reductions in spawning success, smolt production, recruitment into harvestable fishery stocks, and spawning escapement (run size) to the American River. Lower salmon contributions from the American River significantly reduce California coastal and river salmon fishery stocks. Poor production in the American River contributed to the closure of California salmon fisheries in 2023-2025.

During the 2020-2022 drought, Reclamation released water from the lower-level power bypass (sacrificing hydropower production) to provide the cold water (<55ºF) salmon needed for spawning in the ten-mile spawning reach from Nimbus Dam (near Fair Oaks gage) to the William Pond gage (Figure 1). This is the prime spawning reach for salmon in the lower American River. However, in the fall of the wetter years 2023-2025, Reclamation did not use the power bypass to release cold water (Figures 2 and 3), despite higher storage levels than during the drought (Figure 4). The lack of cold water delayed natural spawning and hatchery egg taking, to the detriment of egg viability, fry production, and smolts reaching the ocean.

Ultimately, the number of adult salmon returning to the American River to spawn (escapement) is the important measure of success. There are many factors that may contribute to the number of returns. Recent returns are up (Figure 5). The 2023 and 2024 returns were good despite having been the product of the 2020-2022 drought reproduction (Figurer 6). Closed fisheries in 2023 and 2024 contributed to higher escapements.

I also believe efforts to improve fall water temperatures below Folsom during the drought improved both the wild and hatchery components of escapement. I remain concerned that a return to warmer fall water temperatures will hinder future escapement.

I am also concerned with apparent efforts to sustain higher fall 2025 reservoir levels (see Figure 4) by reducing tailwater stream flow rates (Figure 7). Such low flows reduce the quantity and quality of salmon spawning habitat. Many critical spawning side channels become dewatered at such low flows¹. Main channel velocities, substrate, and depths are also compromised at low flow rates.

Reclamation also reduced funding for the salmon hatchery and for river habitat projects in 2025, and will likely do the same in subsequent years. This strategy will not help to recover American River salmon stocks to levels that once again can contribute toward commercial and recreational salmon fisheries.

Figure 1. Map of three CDEC gaging stations on the lower American River.

Figure 2. Average daily water temperatures in Nov-Dec period at William Pond gage 2021-2025. Red line (55ºF) denotes upper safe level for Chinook spawning.

Figure 3. Average daily water temperatures in November period at Fair Oaks gage 2021-2025. Red line (55ºF) denotes upper safe level for Chinook spawning.

Figure 4. Late summer and fall Folsom Reservoir water storage (acre-feet) 2021-2025.

Figure 5. Adult salmon escapement estimates for the American River 1975-2024. Source: Grand Tab.

Figure 6. American River spawner/recruit relationship – { log10(escapement) -3.5]. Number is year of escapement (recruits). Color denotes water year type two years prior. Red is dry, green is normal, and blue is wet. Note escapement in 2023 and 2024 are red, denoting spawning and rearing occurred two years earlier in dry water years.

Figure 7. Streamflow (daily average) in the American River at Fair Oaks gage Aug-Nov period 2021-2025.

https://calsport.org/fisheriesblog/?p=3507 ↩

Prognosis for the 2026 Salmon Season

Posted on November 28, 2025 by Tom Cannon

Since the year 2000, Fall Run Salmon adult escapement (run total) to the Sacramento River system (mainstem and tributaries) dropped from a peak of 400,000-800,000 to 100,000 or less (Figure 1). The lowest escapement, near 50,000 in 2009, occurred with the fishery closed. More recently, escapement fell below 100,000 in 2017 and 2022, with the fishery open. With the fishery closed in 2023 and 2024, escapement increased to near 150,000, allowing for a very limited recreational fishery in 2025.

The fishery harvests are about 50% of the fishable stock (or what could be available for escapement, see Figure 2). A normal fishery would lead to escapements under 100,000 in recent years. These escapement levels would likely lead the Pacific Fisheries Management Council and California Fish and Game Commission to restrict the fishery again in 2026.

However, the agencies may be inclined to allow a fishery with some restrictions based on positive trends in habitat conditions and the higher jack salmon numbers in the limited 2025 fishery. Water years 2023 and 2024 were relatively wet, which often leads to good survival conditions, and is likely to lead to a projection of good salmon numbers available in 2026.

I am inclined to greater optimism for 2026, as I was in 2025,¹ because of the likely higher numbers of salmon in the ocean and potentially returning to the rivers next year. The various factors supporting my reasoning are summarized below:

Jack numbers were up based on escapement surveys, agency test fisheries, and the limited 2025 fishery.
Brood years 2023 and 2024, which will make up much of the fishable stock in 2026, likely had good survival and production in wet year 2023 and above-normal water years 2024 and 2025 (compared to dry years 2020-2022). Fishery impacts to these broodyears were also minimal in 2024 and 2025.
Hatchery smolt production in 2023-2025 was also good, with some improvements over the 2020-2022 drought years. Hatchery smolts released to the rivers near the hatcheries likely had a much improved survival rate in 2023-2025 over that in the drought years, because of higher transport flows. Millions of hatchery smolts trucked to Bay and coast pens for release also had improved survival compared to river releases.
Fishery restrictions in 2023-2025 likely improved wild salmon spawning numbers, leading to good wild salmon recruitment in the three wetter years.
A 2026 fishery would likely benefit from good overall broodyear 2023 and 2024 survival and production.
My estimate of the fishable stock of broodyears 2022-2024 in the ocean is 400,000-800,000 two-to-four year-old salmon. Under a 50% harvest, escapement in 2026 would be 200,000-400,000 (likely somewhat less, as not all the fishable stock would spawn in 2026). I support this hypothesis with a descriptive Spawner-Recruit model that I developed (Figure 3) that has reasonably predicted escapement in the past several years.

If the fishery remains restricted for a fourth year in a row, escapement could reach or exceed 500,000 adult salmon, a number far in excess of the management target escapement of 120,000-180,000. Such a case would unnecessarily deprive commercial and recreational fisheries of the potential harvest of 200,000 or more adult salmon in the ocean and rivers in 2026.

I remain concerned with the potential adverse effects on wild salmon stocks from fishery harvest (Figure 4). Limiting wild salmon harvest by adjusting fishery timing and location, restricting catches to marked hatchery fish (mark-selective fishery rules), and improving spawning, rearing, and migrating habitat, could help address these issues.

I am also concerned with the poor returns (escapement) from the Coleman Hatchery’s in-river smolt releases that result in low fishery contributions, low escapement (Figure 5), and high rates of adult spawner straying to other spawning streams. To address this problem agencies have considered higher smolt production, increased near-hatchery releases, trucking smolts to Bay-Delta-Coast, transporting eggs to Coleman from other hatcheries, hatchery fry releases to river floodplain and estuary habitats, reducing in-river predators, and improving migrating habitat during smolt releases. All of these measures could help minimize the extent of this problem.

Figure 1. Note the very high escapement around the turn of the century. The improvement is attributable to the wet decade (1995-2005), increased hatchery production, trucking hatchery smolts to the Bay-Delta, and more protective management of fisheries and water supply. Subsequent poor escapement periods are generally attributed to multiyear drought impacts and over-fishing of drought-impacted salmon broodyears.

Figure 2. A 50% harvest rate is about what has occurred over the recent decade under normal fishery regulations.

Figure 3. This complicated semi-quantitative spawner-recruit model display attempts to show that a normal spawner-recruit relationship is overwhelmed by hatchery, harvest, and water-year hydrology effects on recruitment. I predict 2026 escapement (recruits) with a normal fishery will fall into the green box (200,000-400,000) because 2023 and 2024 were wetter (blue) water years. Without a fishery, escapement would be near or above 500,000, a number well above the target escapement.

Figure 4. These spawner estimates for the upper Sacramento River represent the natural spawning escapement of the mainstem Sacramento River. The decline in this escapement component is considered a key factor in the overall decline of the Sacramento River fall-run salmon population. The decline is generally attributed to increasingly poor habitat conditions (water flows and temperature, pollution, predation, and water diversions) and over-harvest of wild or natural-born fish in the fishery.

Figure 5. Adult fall-run salmon returns to the Coleman Hatchery in the upper Sacramento River have been below 10,000 for several years. Preliminary estimates for 2025 indicate sharply higher returns to the Coleman Hatchery (near 40,000 or higher), the result of good hatchery smolt survival, no fishery for three years, and good river conditions this summer and fall.

https://calsport.org/fisheriesblog/?p=4822 ↩

The 2025 Sacramento River Salmon Run – Early Summer Conditions were poor

Posted on November 3, 2025 by Tom Cannon

The limited 2025 salmon fishing season opened in mid-July and continues through October on the Feather, American, and Mokelumne rivers. Early summer (July-August) conditions were tough for the beginning of the run and early fishing. The river, Delta, and Bay in August were too warm despite three wet years in a row with above average reservoir storage and below normal summer air temperatures.

The lower Sacramento River was too warm (Figure 1). Flows dropped in mid-August with two-thirds of reservoir releases being diverted before reaching the Delta. Water temperatures were above the 20ºC standard to protect salmon during their run from the ocean to the rivers. River flow should be near 10,000 cfs to maintain the water temperature standard.

The Delta was too warm (Figure 2). Water temperatures in August reached the 22ºC level, considered highly stressful and avoided by salmon, as Delta inflow dropped from 20,000 cfs to 10,000 cfs. Delta inflow at Freeport should be about 20,000 cfs for good fishing conditions.

The Bay was too warm (Figure 3). Water temperatures exceeded 22ºC, and dissolved oxygen fell to near the standard of 6 mg/ l. Delta outflow fell to near 4000 cfs, while south Delta exports exceeded 10,000 cfs. Delta outflow should be around 10,000 cfs for good fishing conditions.