Author Archives: Tom Cannon

Prognosis for the 2026 Salmon Season

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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:

  1. Jack numbers were up based on escapement surveys, agency test fisheries, and the limited 2025 fishery.
  2. 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.
  3. 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.
  4. Fishery restrictions in 2023-2025 likely improved wild salmon spawning numbers, leading to good wild salmon recruitment in the three wetter years.
  5. A 2026 fishery would likely benefit from good overall broodyear 2023 and 2024 survival and production.
  6. 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.

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

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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.

Figure 1. Lower Sacramento River streamflow and water temperature in July-August 2025. Red line is the water quality standard for water temperature.

Figure 1. Lower Sacramento River streamflow and water temperature in July-August 2025. Red line is the water quality standard for water temperature.

Figure 2. Streamflow and water temperature of the Sacramento River at northern entrance to the Delta over the past 30 days.

Figure 3. Water temperature and dissolved oxygen concentration in the east Bay in July-August 2025.

The Fall-X2 Action – Benefits and Costs

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The 2008 Delta Smelt Biological Opinion for Central Valley Project (CVP) and State Water Project (SWP) operations included the Fall X2 Action to protect Delta smelt. The about-to-be implemented “Action 5” that will modify the 2024 biological opinions for the CVP and SWP will eliminate the Fall X2 Action entirely.

The Fall X2 Action required the CVP and SWP to keep brackish water west of the Delta in September and October in wet and above normal water years. The X2 location is defined as the location where salinity is 2 parts per thousand.1 X2 is located within what is known as the low salinity zone (LSZ, 1-6 parts per thousand).

Delta smelt and longfin smelt concentrate in the LSZ near X2 in summer and fall. Keeping X2 at Chipps Island (KM 71 from the Golden Gate, Figure 1) benefits the populations of Delta smelt and longfin smelt. Less effective options for the Fall X2 Action that require less Delta outflow have included other locations as far east as KM 80.

If freshwater outflow from the Delta is too low (at or below about 6000 cfs), the LSZ is located within the narrow channels of the west Delta. Water in the west Delta tends to be warmer and less productive than water in Suisun Bay. It is also more likely to be pulled south by pumping at the CVP and SWP’s south Delta export facilities.
The higher freshwater inflows needed for the Fall X2 Action also benefit other native fishes in the lower Sacramento River, its tributaries, and the Delta.

Harm comes to Bay-Delta fish in the form of high water temperatures and reduced food concentrations. When water temperatures climb into the range of 70-72°F, native fishes, including smelt, sturgeon, steelhead, and salmon, generally suffer stress-related poor growth and survival.

Warm Delta water blocks or hinders adult salmon in their upstream spawning migrations. (A water temperature of 72°F is the salmon avoidance temperature.) Adult salmon will hold in the Bay because of warm water temperatures, resulting in delayed spawning and the expenditure of the critical energy needed for spawning. Warm rivers cause further delay, diseases, and thiamine deficiency, reducing the ability of salmon to spawn successfully. Higher water temperatures (> 65°F) during spawning migrations also lead to reduced salmon egg and embryo survival. High water temperatures in juvenile rearing habitat and emigration routes lower the growth and survival of juvenile salmon, steelhead, smelt, and sturgeon, and increase predation on all these species.
In the Delta specifically, high water temperatures in the Delta block emigration of juvenile salmon and reduce growth rates and survival of juvenile salmon and smelt. Both salmon and smelt species are highly sensitive to warm and varying water temperatures. Heat transfer and retention during high air temperatures from late-spring to early-fall is greater at lower flows.

In summary, water temperatures above 72°F are highly stressful on native Bay-Delta fishes, often leading to poor growth, low-oxygen stress, more disease, greater susceptibility to predation, and competition from non-native fish, all of which lead to reduced survival. Also, many non-native fish such as largemouth bass thrive in higher water temperatures (72- 80°F).

The Fall X2 Action
The Fall X2 Action focuses on increasing Delta inflow and outflow in the months of September and October when seasonal flows are naturally lower and irrigation demands less, while air temperatures remain high. Late summer and early fall are a key period in the life cycle and overall reproductive success of many Bay-Delta native fishes.

Bay-Delta
The Fall X2 Action is needed to maintain low salinity and water temperature in the optimal range of native Bay-Delta fish. In the 2017-2019 period, with two wet years and one below-normal year, the higher prescribed Delta outflow (DTO) of the Fall X2 Action (Figure 2) in the wet years kept the Bay fresher (Figure 3) and Delta outflows cooler (Figures 4 and 5). In the two above-normal years of 2024 and 2025, the lack of a Fall X2 Action in September 2025 (Figure 6) led to high September water temperatures in the western Delta (Figure 7). The lack of Fall X2 Action in October 2024 (Figure 6) contributed to stressful (>65º F) October water temperatures at Rio Vista bridge in the west Delta (Figure 7). 2020, a below normal water year, provides another example of high September-October water temperatures when the Fall X2 Action was not implemented (Figure 8).

Lower Rivers
The Fall X2 Action requires roughly 5000 cfs of extra Delta inflow for two months (assuming needed flow is not provided by foregone river diversions or Delta exports). Releases from Shasta, Oroville, and/or Folsom reservoirs generally provide this inflow. That amounts to roughly 10,000 acre-feet of water per day, or 600,000 acre-feet for the full September-October period. In recent wetter water years, the CVP and SWP have offset some (or all) of this water cost by reducing reservoir releases in the summer and not meeting water quality standards for water temperatures in the lower Sacramento River. Flows in the lower Sacramento River at Wilkins Slough have been near 5000 cfs, when it takes about 10,000 cfs to maintain the 68º F standard.

The Cost
In summary, the amount of fresh water required to keep X2 in Suisun Bay in late summer and early fall of above-normal and wet water years requires approximately 600,000 acre-feet of stored project water or forgone diversions from rivers and exports from the Delta. That amounts to about 5% of total CVP and SWP storage capacity. It is also about 5% of the total annual upstream, in-Delta, and Delta export water use in the Bay-Delta watershed.

The about-to-be implemented “Action 5” that will modify the 2024 biological opinions for the CVP and SWP will eliminate the Fall X2 Action, and this water cost, entirely.

Figure 1. Bay-Delta and key water accounting and water quality locations.

Figure 2. Daily average Delta outflow (cfs) in September-October of water years 2017-2019. Fall X2 Action was implemented in wet year 2017 and 2019.

Figure 3. Salinity (EC) of east Bay near Chipps Island at Mallard Slough 2017-2019.

Figure 4. Water temperature in west Delta at Emmaton in September-October 2017-2019.

Figure 5. Water temperature in west Delta at Rio Vista in September-October 2017-2019.

Figure 6. Daily average Delta outflow (cfs) in September-October of above-normal water years 2024 and 2025. Fall X2 Action was implemented in September of 2024 and October of 2025.

Figure 7. Water temperature in west Delta at Emmaton and Rio Vista in September-October 2024 and 2025.

Figure 8. Daily average Delta outflow (cfs), Freeport river flow, and Emmaton and Rio Vista water temperature in July-October of water year 2020. The Fall X2 Action was not implemented in below-normal water year 2020.

  1. Also measured as about 3000 EC.  See https://pubs.usgs.gov/sir/2014/5041/pdf/sir2014-5041.pdf ↩

2025 Sturgeon Moon

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The 2025 Sturgeon Moon (August 9 full moon) wreaked havoc on San Francisco Bay as it had in recent years1. The main effect was warm fresh water from the Delta draining into the Bay (Figure 1). The tidal effect of the super moon dropped water levels sharply about two weeks before the super moon (Figure 2). Warm water built up in the Bay over several days (Figure 3). A plankton bloom appeared in the North Bay soon thereafter (Figure 4). Is anyone checking on the sturgeon in the Bay? Will the coming heat waves over-heat the Bay?

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Figure 1. Fresh water drained into the Bay at Martinez for several days in late July, beginning about 14 days prior to the full moon.

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Figure 2. Water level of the Bay at Martinez July and early August 2025.

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Figure 3. Water temperatures increased at Martinez with the warm inputs from the Delta and Suisun Bay.

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Figure 4. Small plankton blooms appeared around the peripheries of San Pablo and Suisun bays and in Montezuma Slough at the end of July with the warm freshwater inputs. Source: https://www.cbr.washington.edu/sacramento/data/query_river_graph.html

 

California Salmon Fisheries in 2025

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Graph showing 2025 SI forecast

The government forecast for adult fall-run salmon available along the coast to target for harvest in 2025 is 165,655 (black dot is number for 2025 in above Figure 1).  That number is only slightly higher than the 122,000 target minimum to allow some harvest.  The fishery was closed in 09, 10, 23, and 24.  The model used for the estimate is crude at best – based primarily on two-year-old escapement the prior year.

I have my own model based on the number of spawners (escapement) three years earlier (Figure 2).  The model did pretty well predicting 2023 and 2024.  For 2025 I guessed as best I could and came out with similar numbers as the government.  There are probably between 150 and 250 thousand salmon out there this summer available for salmon fisheries.

My guess is that the government is not going to offer a salmon fishery this year based on the poor numbers in the fishable stock, the predominance of hatchery fish, and record low numbers of wild salmon stocks.  Though a reasonable conclusion under the present circumstances, I think it is a mistake for the following reasons.

  1. Though spawner numbers were low in drought year 2022, conditions in winter-spring of wet year 2023 were very good (a blue year) for juvenile survival to the ocean.
  2. Most of the 20 million or so fall-run hatchery smolts were released to good river or Bay conditions in 2023. Millions were released to net pens in coastal waters near the Golden Gate Bridge, in Half Moon Bay, and in Monterey Bay locations where salmon smolt survival has been exceptionally high.
  3. The Mokelumne River Hatchery has been producing record runs of fall run salmon in recent years by releasing millions of smolts to Bay and Coastal waters.
  4. The fishery has been closed for two years, leaving more fish from brood years 2021-to-2023 in the fishable stock.
  5. Ocean conditions in 2023 and 2024 were relatively good.
  6. Water year 2025 is shaping up to be a relatively wet year providing good conditions for returning adult salmon.
  7. Overall, many hatchery-produced salmon would simply go to waste and compete with wild salmon for precious spawning habitat.

One caveat remains – the poor state of wild, naturally spawning salmon.  Their populations likely would suffer from the loss of spawners to harvest.

Therefore I recommend consideration of a mark-selective fishery that allows harvest only of hatchery fish with adipose fin clips, but that requires release of unmarked salmon (hatchery and wild).  California steelhead fisheries have such regulations.  Many coho and chinook salmon fisheries in the Pacific Northwest have such regulations.  Special regulations on season, area, and size can serve to protect non-target salmon such as spring-run and winter-run listed salmon or recovering Klamath River salmon.  Such a fishery should be experimental, with an extra dose of monitoring, assessment, progress reporting, stakeholder involvement, and adaptive management.

The fishery harvest would be severely limited, as only about 25% of hatchery smolts are marked.  Only about one in five salmon caught will have an adipose fin removed allowing harvest, reflecting 25% proportional marking and 20% of the harvestable fish being wild or natural born.  This may limit the feasibility of commercial fisheries and result in greater effort and fish handling.

Overall, such a limited fishery would likely be better than none at all when measured in terms of cultural and socioeconomic value.

Spawner-recruit relationship graph for Sacrament River Fall Run Chinook Salmon