Welcome to the California Fisheries Blog

The California Sportfishing Protection Alliance is pleased to host the California Fisheries Blog. The focus will be on pelagic and anadromous fisheries. We will also cover environmental topics related to fisheries such as water supply, water quality, hatcheries, harvest, and habitats. Geographical coverage will be from the ocean to headwaters, including watersheds, streams, rivers, lakes, bays, ocean, and estuaries. Please note that posts on the blog represent the work and opinions of their authors, and do not necessarily reflect CSPA positions or policy.

Scott-Shasta River Salmon Update – February 2024

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The upper Scott River near Callahan in early spring of drought year 2013.

At the end of November 2023, the Beaver Moon, the last full moon before December, appeared. The Beaver Moon was so named because it was the last chance for trappers to catch beaver with full coats before winter set in. The Beaver Moon also occurs at the peak of the Coho and Chinook salmon runs in the Scott River Valley, once named Beaver Valley. The beaver were once very abundant before being “removed” by ranchers and trappers. Today, beaver are slowly coming back. The beaver help maintain the local groundwater tables, streamflow, water temperatures, riparian vegetation, and create good coho salmon rearing habitat.1

The State Water Resources Control Board took up the Scott and Shasta Rivers water issues again in fall 2023,2 following its adoption of emergency drought regulations in 2022 and a 2023 petition from the Karuk Tribe and environmental organizations3 to protect salmon and steelhead in the Scott river in all water years.

The emergency regulations for 2022 called for summer minimum flows of 30-50 cfs in the Scott River and 50 cfs in the Shasta River. Such minimums were not achieved on the Scott River (Figure 1), but for the most part were achieved on the Shasta River (Figure 2). Such flows were necessary for two key flow functions: (1) maintaining connectivity between spawning and rearing areas in the valleys and the Klamath River, and (2) sustaining over-summering rearing habitat of salmon and steelhead throughout the two rivers and their tributaries.

Without adequate summer flows, salmon fry become trapped in upstream spawning areas without access to productive spring-fed Valley rearing habitat. Maintaining flow in Valley spring-fed habitats provides connectivity and rearing refuges. Late summer and fall minimum flows are necessary to provide access to the valleys from the Klamath River canyon for salmon and steelhead adult spawners.

The State Board should have kept some emergency order elements in place after the orders ended in July 2023, even though 2023 was a wet year. In 2023, both rivers and their salmon were stressed again by low flows (Figures 3 and 4).

Because base flows from mountain and valley springs are just over 100 cfs in both streams, stressful conditions are brought on by the cumulative effects of small water diversions and groundwater pumping. Surface water diversions and groundwater extraction for agricultural and domestic water use draw from this supply, with peak use in the summer-fall irrigation season. On the Shasta River, the irrigation season ends at the beginning of October, allowing flows from springs to fill the river channel for returning salmon. On the Scott River, the irrigation season extends through November to water pastures and to get in the last crop of hay.

In the Shasta River, flows in October are sufficient for Chinook spawners passage to spawning areas around Big Springs in Shasta Valley. But in the Scott Valley, Chinook often do not have adequate passage flows to ascend from the Klamath Canyon up to Scott Valley until the first late-fall rains. In most years, early December rains accommodate the Coho run in the Scott River. Young salmon from the prior year’s spawning also need the fall flows to emigrate from the Valley to the Klamath River and ocean.

2023 Karuk et. al. Petition for Scott River4

On May 22, 2023, the Karuk Tribe, Environmental Law Foundation, Pacific Coast Federation of Fishermen’s Association, and Institute for Fisheries Research petitioned the State Water Board to initiate a rulemaking to establish permanent (not just emergency) instream flows on the Scott River.

As an initial response, the State Water Board re-adopted, on an emergency basis, the emergency minimum instream flows previously in effect in both the Scott River and Shasta River.

Comment: The State Board did not readopt the emergency regulations in wet year 2023 and the salmon suffered.

2024 Coastkeeper et al. Petition for Shasta River

On January 17, 2024, California Coastkeeper Alliance, Friends of the Shasta River, Mt. Shasta Bioregional Ecology Center, Water Climate Trust, Shasta Waterkeeper, Save California Salmon, and Environmental Protection Information Center petitioned the State Water Board to initiate a rulemaking to establish permanent (not just emergency) instream flows on the Shasta River.

Recommendations

As an initial matter, the State Water Board should adopt as permanent the minimum instream flows it adopted on February 1, 2024 as emergency instream flows.5 This will put an immediate end to dry streambeds in the summer and fall as shown in Figures 3-5 below. This will admittedly also significantly reduce water available for human use and cause a conflict between groundwater and surface water users, as well as among water right holders.

In the longer term, there are some relatively straightforward additional measures that could help create solutions to the problems in Scott and Shasta Valleys and potentially reduce the water supply impacts. Whether these actions are equitable, reasonable, cost-effective, and/or politically doable is open to question and evaluation. The adoption of the flow requirements as shown must not be contingent on the implementation or effectiveness of such actions.

Possible additional measures include:

  1. Create additional instream or off-stream storage to capture winter water for summer release to meet demands and needs.
  2. Make concerted efforts to recharge groundwater storage with the often-plentiful winter-spring runoff.
  3. Deepen the river channel by removing accumulated fine and course sediments to enhance channel access to groundwater. Removing Young’s Dam in the middle Scott Valley would deepen channel upstream and alleviate the dam’s impediment to salmon and steelhead migration.
  4. Eliminate all surface water diversions from stream channels. There are many small water diversions from the Scott and Shasta rivers that divert streamflow and juvenile salmon. Surface diversions should be replaced by a regulated groundwater extraction program.

    Small water diversion on a Scott River tributary. All small and larger surface diversions should be eliminated. The present system was controlled by the state watermaster program that no longer covers the Scott River and its tributaries.

    Small water diversion on a Scott River tributary. All small and larger surface diversions should be eliminated. The present system was controlled by the state watermaster program that no longer covers the Scott River and its tributaries.

  5. Use unused well capacity to temporarily augment surface water flow in the streams in late summer to help with salmon migrations and to accommodate spawners. In Scott Valley, many hay producers cease pumping from wells at the beginning of August or September. A monitoring and evaluation program would be required to avoid long-term impacts to groundwater levels. The target flow in both the Scott River and Shasta River should be near 100 cfs by October 1 at the Fort Jones and Yreka gages, respectively.
  6. Enhance and restore water storage in mountain and valley meadows through watershed management, including introductions of beaver.
  7. Institute an aggressive water conservation program in the two watersheds.

Latest Actions

 The petitioners requested the following:

Drought emergency minimum flows are specified below:

 Scott River:

  Shasta River:

 The State unveiled the California Salmon Strategy for a Hotter, Drier Future:  Restoring Aquatic Ecosystems in the Age of Climate Change on January 31, 2024.  The Strategy describes state actions for the Scott and Shasta rivers, as follows:

 Scott/Shasta:

  • Designate Salmon Strongholds: the Klamath River and its tributaries including the Salmon, Scott, and Shasta rivers.
  • In April 2023, CDFW awarded $20 million in Drought Emergency Salmon Protection Grants to 10 projects demonstrating support from and collaboration with Tribal Nations and landowner interests in the Shasta and Scott rivers and their watersheds. These include habitat improvement, removal of barriers to fish passage, and groundwater recharge projects that help ensure streamflow.
  • The State Water Board, acting upon a petition from the Karuk Tribe, began consideration of an emergency regulation in 2023 to set emergency minimum flows for the Scott and Shasta rivers while a longer, inclusive process evaluates long-term strategies for these salmon strongholds.
  • By early 2024, commence work to establish minimum instream flows in the Scott and Shasta Rivers, working with local partners on locally driven solutions and coordinating on options for incentivizing the reduction of diversions and groundwater pumping. (SWRCB, CDFW)
  • Currently, with state funding support, the Yurok Tribe, the Karuk Tribe, California Trout, Scott River Water Trust, and Farmers Ditch Company are developing a design-build project to restore habitat in the Scott River and improve water diversion infrastructure for on-farm water utilization and efficiency.

 For more on the Scott River issues see: https://calsport.org/fisheriesblog/?p=1608 .

Figure 1. Scott River streamflow in 2021 and 2022 at Fort Jones gage. Note the end of the irrigation season in November-December. Note also prescribed emergency flows were not met in 2022.

Figure 2. Shasta River summer 2021 and 2022 streamflow at the Yreka gage. Note the end of the irrigation season on October 1st. Note also prescribed emergency flows were met in 2022 with the exception of about a one-week period in August.

Figure 3. Scott River streamflow in summer-fall 2023 at Fort Jones gage. Note the July 2023 flow reduction when the emergency flow regulations ended. Note also the end of the irrigation season on December 1st.

Figure 4. Shasta River summer 2023 streamflow at the Yreka gage. Note the July 2023 flow reduction when the emergency flow regulations ended. Note also the end of the irrigation season on October 1st.

Figure 5. Scott River in Scott Valley in August 2013. The riverbed is perched above the water table that was low due to groundwater extraction for hay and pasture watering.

Figure 6. Lower Valley location of Scott River at the mouth of Shackleford Creek, a major salmon spawning tributary, on October 26, 2013.

Figure 7. Young’s Dam and fish ladder. Portions of the dewatered Scott Valley stream are located in the perched channel upstream of Young’s Dam. Under low late-summer streamflows, the ladder at Young’s Dam is not functional and blocks the Chinook migration. The channel upstream of the dam is wide and perched above the water table, so it is often too warm, with insufficient flow and cover, for rearing salmon. In contrast, the channel below the dam is deep and shaded with spring-fed juvenile salmon refugia.

  1. Beaver dams sometimes block salmon migrations.  In Alaska, biologists sometimes resort to blowing up dams with dynamite.  On the Yuba River near Brownsville, biologists in recent decades had to “dismantle” some dams to allow salmon access to tributary creek spawning habitat. ↩
  2. https://www.times-standard.com/2023/08/22/minimum-flows-set-for-scott-river-in-state-water-board-meeting/ ↩
  3. https://www.waterboards.ca.gov/drought/scott_shasta_rivers/docs/2023/petition-minimum-flows.pdf ↩
  4. https://www.waterboards.ca.gov/waterrights/water_issues/programs/drought/scott_shasta_rivers/docs/2022/klamath-reg-2022.pdf ↩
  5. State Water Board, Emergency Regulation Scott River & Shasta River Watershed, February 1, 2024:  https://www.waterboards.ca.gov/drought/scott_shasta_rivers/docs/2024/scott-shasta-reg-oal-approval-2024.pdf. ↩

Salmon in 2024

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Salmon in the ocean off the coast of California in 2024 will consist primarily of Central Valley hatchery fish ages two, three, and four.  They were released primarily as sub-yearling smolts in 2021, 2022, and 2023 (born in the fall of broodyears 2020, 2021, and 2022 respectively).

Feather River Hatchery

The Feather River Hatchery released approximately 8 to 10 million fall-run salmon smolts in the spring of each release year.  All were trucked to the Bay or coast, except for 1.5 million released to the lower Feather River in April of wet year 2023.  My guess is that the number of the fishable salmon in the ocean that are 2-to-4-year-old fall-run Feather hatchery fish could be 500,000 fish in 2024, with 125,000 marked with an adipose fin clip.  The hatchery also released another 6 million spring-run smolts in the three years – all marked.  The total marked salmon in the 2024 fishable stock will likely be about 150,000.

American River Hatchery

The Nimbus Hatchery released 4 to 5 million fall-run smolts per year from 2021 to 2023.  Nearly all were trucked to the Bay or coast.  My guess is that about 50,000 of Nimbus broodyear 2020-2022 marked salmon will be in the fishable stock in 2024.

Mokelumne River Hatchery

The Mokelumne Hatchery released approximately 6 million fall-run smolts per year from 2021 to 2023.  Nearly all were trucked to the Bay or coast.  My guess is that about 100,000 of Mokelumne broodyear 2020-2022 marked salmon will be in the fishable stock in 2024.

Coleman (Battle Creek) Hatchery

The Coleman Hatchery released approximately 10-12 million fall-run smolts per year from 2021 to 2023.  Nearly all were released at or near the hatchery.  My guess is that about 25,000 of Coleman broodyear 2020-2022 marked salmon will be in the fishable stock in 2024.

Other Central Valley Salmon Hatcheries

The three smaller salmon hatcheries release about one million salmon smolts per year near the hatcheries, about half of which are marked.  My guess is that about 5,000 of broodyear 2020-2022 marked salmon from these hatcheries will be in the fishable stock in 2024.

Klamath/Trinity Salmon Hatcheries

Klamath/Trinity has two hatcheries that release a total of 4-5 million smolts per year.  I have not included them in this assessment.

Summary

My guess is that there will be about 330,000 marked hatchery salmon from the Central Valley salmon hatcheries in the 2024 fishable stock, not counting Klamath/Trinity or Oregon/Washington marked stocks that occur in small numbers off the California Coast.  The number is similar in size to the NMFS/PFMC Sacramento Index that is the basis of salmon harvest management for coastal and inland salmon harvest (see chart below).  Though the estimates are complicated and only crudely comparable, they are a reasonable basis for developing a 2024 fishery harvest strategy.

Recommendation

I suggest a harvest of up to 200,000 of the marked salmon only in a California mark-selective fishery in 2024.  That is a total harvest similar to the average over the past decade, but with protection built in to minimize harvest of wild, natural born (unmarked) salmon and the unmarked portion of hatchery releases.  There is concern for marked listed hatchery winter-run and spring-run salmon that would need consideration, but these fish are generally protected through seasonal and area restrictions.  Regulations and monitoring specific to a mark-selective fishery would have to be put in place.  Experience in the Pacific Northwest indicates mark-selective fisheries are a viable alternative to closed fisheries.

Status of Winter Run Chinook Salmon in the Sacramento River – A Poor 2023 Run

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The latest carcass count survey indicates another near-record low-run of winter-run salmon in the upper Sacramento River in 2023 (Figure 1). Most of the spawning occurred in June and July 2023 (Figure 2). The official total winter-run escapement includes hatchery returns, Battle Creek counts, and fishery harvest, but is not available yet for 2023 (Figure 3). The low 2023 spawning census count can be directly attributable to broodyear 2020’s poor spawning, incubation, rearing and emigration conditions in below normal water years 2020 and critically dry year 2021.1

Broodyear 2020 started as eggs and milt in their parents in winter-spring of 2020. They were spawned and hatched in summer 2020. They began moving downstream in late fall 2020, rearing and emigrating in the lower river and Bay-Delta, and finally reaching the Bay and ocean in winter-spring of critically dry year 2021. The juveniles that survived returned as three-year-olds in winter-spring of 2023.2 Broodyear 2021 (two-year-olds in the 2023 run) were also subjected to drought conditions, spawning, rearing, and emigrating in 2021 and 2022 before returning in 2023.

Major stresses on young broodyear 2020 salmon included:

1. Broodyear 2020 spawners and their eggs and embryos were subjected to less-than-optimal water temperatures during the May-August 2020 spawning season (Figures 4 and 5).

2. Flows remained very low from September 2020 through January 2021 (Figure 6). Water temperatures were also stressful during fall 2020 (see Figure 5). Without flow pulses in fall and winter, young winter-run salmon survival was poor (Figure 7), with delayed emigration (Figure 8).

Major stresses on adult salmon from broodyear 2020 that returned to spawn in 2023 included:

3. Upon returning in spring 2023 to spawn, broodyear 2020 adults were subjected to stressful water temperatures in May and June in the lower Sacramento River (Figure 9).

4. During the adult winter immigration period, two two-week-long flood events resulted in about half the Sacramento River flow passing into the Sutter and Yolo Bypass via overflow weirs (Figure 10). Large numbers of adult winter-run from broodyear 2020 were likely attracted into the flow from these bypasses. Those passing upstream via the bypass channels are subject to being blocked at the overflow weirs or stranded in bypass channels. Large fish passage “notches” are currently being constructed at the larger Tisdale and Fremont Weirs, but they are not expected to be operational until late in 2023 at the earliest. Large numbers of adult winter-run from broodyear 2020 were likely lost in the bypasses in winter 2023, as they were in past wet years.

In summary, poor numbers of winter-run broodyear 2020 spawners returned to the Sacramento River in 2023 despite the fact that the ocean and river salmon fisherieswere closed under an emergency order. The low numbers of spawners is attributable to poor river conditions in 2020 during spawning, rearing, and emigration, and in 2023 during the adult run up the Sacramento River in winter-spring.

Figure 1. Winter-run salmon carcass counts in spawning reach near Redding from 2003-2023. Five lowest tallies occurred two years after critical drought years 2008, 2009, 2014, 2015, and 2021. Source: USBR

Figure 2. Carcass counts by calendar week in 2023. Peak counts were in July (weeks 27-30). Source: USBR

Figure 2. Carcass counts by calendar week in 2023. Peak counts were in July (weeks 27-30). Source: USBR

Figure 3. Winter-run salmon escapement includes the carcass survey, hatchery returns, and Battle Creek returns. Source: CDFW GrandTab.

Figure 4. Water temperature in the Sacramento River in 2020 below Keswick Dam and above the mouth of Clear Creek – the upper ten miles of river in which winter-run salmon spawn. Red line is recommended water temperature threshold for these locations for salmon spawning and egg incubation. Source: www.cbr.washington.edu/sacramento/

Figure 5. Threshold analysis for 2020 in upper Sacramento River. KWK=Keswick Dam. SAC=Redding. CCR=Above Clear Creek. BSF=Balls Ferry. JLF=Jelly’s Ferry. BND=Bend Bridge. Source

Figure 6. Lower Sacramento River flow rate September 2020 to March 2021.

Figure 7. Broodyear index for winter-run salmon young catch at Knights Landing rotary screw trap 2008-2023. Source

Figure 8. Tisdale screw trap collections of winter run smolts in fall-winter of water year 2021. Source

Figure 9. Water temperature in upper Sacramento River at Red Bluff and lower Sacramento River at Wilkins Slough April-July 2023. Red line is target threshold water temperature for winter-spring migrating adult salmon. Source

Figure 10. Water flow through three Sacramento Flood Control Weirs in 2023. TIS=Tisdale. CLW=Colusa. FRE=Fremont.

Table 1. Winter-run salmon hatchery releases percent survival for 2009, 2014, 2015, and 2016 release-year tag groups. Most returns occur at age three two years after release. Note low survival from 2009 releases (<0.03%), 2014 releases (0.03-0.18%), and 2015 releases (0.10-0.21%) in critical drought water years. Higher survival rates (0.40-0.81%) occurred from 2016 releases in a normal water year.

  1. A small portion of the spawners in any year are two-year old jacks and jills. ↩
  2. A few remain in the ocean and may return as 4-yr-olds in 2024. ↩

Why Does the Mokelumne River Hatchery Have a Record Salmon Run this Fall 2023 when Runs at the Battle Creek (Coleman) Fish Hatchery Are at Record Lows?

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Water Year 2023 (10/1/22-9/30/23) in the Central Valley was very wet, with exceptional hydrology. With the state’s salmon fishery closed and plentiful water there had been some optimism for the 2023 salmon runs. But there was also concern as to how much this year’s salmon runs would be affected by the poor water years 2020-2022.

The Mokelumne River system is achieving hoped-for outcomes from its salmon management. Over 20,000 salmon adult salmon have been counted moving upstream past the Woodbridge counting facility. The counting facility on Battle Creek has counted only about 5,000 salmon, in a system whose adult return are generally far greater than those on the Mokelumne. What happened?

  1. Reasons for Strong Run in Mokelumne River – News reports and interviews with hatchery managers indicate a record high escapement of fall-run salmon to the Mokelumne River and hatchery. Factors that likely contributed to the strong run include the following:
    1. Of the 21 million fall-run smolts produced and released by the Mokelumne Hatchery during drought years 2020-2022, about half were released to coastal harbors and half released to Sherman Island sites on the lower San Joaquin River channel in the Delta (Table 1). These releases likely made up the vast majority of Mokelumne River returns in 2023 of age 2-4 adult returns.1 Past survival rates for such coastal and Delta releases are among the highest for Central Valley hatchery fall-run salmon smolt releases. Coastal releases regularly have survival rates 5 times the rates of the Delta releases and 10 or more times the rates of Mokelumne River in-river releases. No releases were made to the Mokelumne River below the hatchery from 2020-2022. Straying rates of adults returning from the Mokelumne Hatchery off-site smolt releases often exceed 50%, with most going to the American River and lesser amount returning to the Feather and Merced rivers. Strays from hatcheries on those rivers also return to the Mokelumne River.
      b. The Mokelumne River has prescribed summer-fall attraction flows for fall-run salmon (Figure 1). However small in magnitude, they seem to attract adult salmon.

  2. Reasons for Poor Winter-Run and Fall-Run Salmon Runs in Upper Mainstem Sacramento River and Battle Creek – News reports and hatchery news releases indicate a very low run for salmon in Battle Creek and the upper Sacramento River in 2023.
    1. a. All hatchery smolt releases from the Coleman Fish Hatchery on Battle Creek and the Livingston Stone Fish Hatchery on the Sacramento River in Redding in 2020-2022 were to the upper river near the two hatcheries. In prior years, survival was low for river releases in drought years and higher for Bay-Delta releases (Table 2).
    2. River conditions in the Sacramento River are generally poor (high water temperatures and low flows) in drought years like 2021 for late winter and early spring hatchery releases and wild salmon emigration. Overall outmigration success in every year but one has been poor since 2008, and is trending downward (Figure 2). However, in late winter and early spring 2021, a natural flow pulse occurred in the upper river that helped move the hatchery and wild smolts downstream (Figures 3 and 4).
    3. Water temperatures in the lower reaches of the Sacramento River were high when adult salmon were migrating upstream towards the upper Sacramento River and Battle Creek (and hatchery) (Figure 5).

Table 1. Tag groups of Mokelumne Hatchery fall-run smolts released in spring by location in 2020-2022 (brood years 2019-2021).

Figure 1. Streamflow of lower Mokelumne River at Woodbridge gage in water years 2020-2022 and long term average. Note October attraction flows and winter pulse flows.

Table 2. Survival table for selected winter-run and fall-run smolt release groups from the Livingston Stone Hatchery and Coleman Hatchery during critical drought years 2009, 2044, 2015 and normal year 2016.

Figure 2. Broodyear index for juvenile fall-run salmon catch in the lower Sacramento River at Knights Landing rotary screw trap 2008-2023. Source

Figure 3. Water temperature and streamflow in the lower Sacramento River at Wilkins Slough in March-April 2021. Red outline is period of (upstream) Coleman Hatchery smolt releases.

 

Figure 4. Tisdale screw trap collections of winter-run smolts in the lower Sacramento River in fall-winter of water year 2021. Source

Figure 5. Water temperatures in the lower Sacramento River at Wilkins Slough and Freeport during adult salmon immigration period in 2023. Green line represents safe level for adult migration. Yellow line is stress level and water quality standard. Red line is high stress and avoidance level.

  1. Only partial 2020-2022 returns have been recorded for broodyear 2019 releases on the RIMS code-wire-tag database. Two-year old returns appear complete and show over 50% of returns to river-hatchery escapement was to the American River, particularly Nimbus Hatchery. ↩

Spring Run Salmon Collapse 2023

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The National Marine Fisheries Service (NMFS), in an  August 2023 Assessment, provided a status review of spring-run Chinook salmon in California’s Central Valley.  The Assessment found that salmon are declining, but primarily as part of a short-term trend, under the burden of climate change.

The conclusions of the August Assessment stand in stark contrast to October’s condor-like effort to preserve remaining wild spring-run salmon in a conservation hatchery at UC Davis.  This contrast demonstrates the limitations of the federal and state resource agencies’ focus on climate change and the ocean as the cause of the salmon declines and the reason to shut down fisheries.1 The resource agencies need to direct more attention to controllable elements: water operations.  On that level, they must take immediate action, before another one of California’s most important public trust resources is lost.

Quotes from NMFS’ 2023 Update to the Viability Assessment for Spring-Run Chinook, and Comments

Populations in many ESUs declined in abundance compared to the previous review five years ago. In most cases, these declines appear to be caused by variation in survival rates in the ocean environment. In the coming decades, climate change, including negative effects in the ocean, is expected to be a major factor impacting Pacific salmon (Crozier et al. 2019). In the near term, however, we generally viewed the recent declines as mostly being short-term and not necessarily indicative of a major underlying change in ESU/DPS status. Several populations within each ESU/DPS were evaluated to have a declining trend in overall viability (i.e., increased extinction risk) since the last review. …  No new information suggests that the delineation of the CVSRC ESU should change at this time. (p. 2) [emphasis added]

Comment:  I generally disagree with NMFS’s conclusions, because these conclusions do not reflect the reality of effects of the 2013-2015 drought or the more recent 2021-2022 drought.  NMFS predicted these effects in its 2016 review, particularly the effects on the freshwater river and estuary habitat conditions, and the roles played by state and federal water management.  Thiamine Deficiency continues to be the theory driving NMFS’s focus on the ocean.  However, NMFS has not addressed alternative theories that water management in freshwater exacerbates the effects of the lower thiamine that stems from ocean feeding on anchovies.

As to the statements that recent declines are “near-term” and that “no new” information warrants a change in the level of risk status for Central Valley spring-run, one must assume that NMFS regrets these conclusions in light of the catastrophic numbers of spring-run spawners in September and October of 2023.

Climate plays an important role in salmon (Oncorhynchus spp.) habitat at every stage of their lifecycle. For instance, predictable seasonal climate variations interact with the physiography of salmon watersheds to provide predictable seasonally varying water temperature and streamflow regimes that create diverse life-history pathways for different salmon populations of the same and different species. Likewise, irregular climate and weather variations like persistent drought, episodic floods, or persistent marine heatwaves, can impact salmon populations by altering their aquatic habitats and food-webs, which in turn affect individual salmon growth and survival rates in ways that can impact salmon populations at local to regional scales. Climate variations impacting regions across 100s to 1000s of kilometers can thus impact ESU/DPS viability through impacts on abundance, productivity, spatial diversity, and distribution. (p. 6) 

Comment:  Water management in the Central Valley can also be a major problem, if not the main problem.  NMFS holds some of the responsibility for this water management, but continues to avoid it.  Yes, droughts have been frequent, but the effects of droughts on salmon have gotten worse because of drought-year water management.  NMFS’s role in 2013-2015 and in 2021-2022 was to quietly acquiesce to the California State Water Resources Control Board’s decisions to grant the requests of state and federal agencies to weaken flow and temperature requirements during drought conditions.

It is NMFS’s responsibility to oppose the federal agencies’ requests to weaken standards during droughts.  Such requests are federal actions.  NMFS continues to act as though it has no authority over the Bureau of Reclamation’s deliveries of water from Shasta and Trinity reservoir water to California’s water contractors.  But these deliveries are most certainly federal actions that require NMFS’s review and approval under the Endangered Species Act (ESA).

The period of 2013–2021 has been exceptional for its high frequency and magnitude of West Coast drought and terrestrial heat, widespread and severe wildfire, and record-setting marine heatwaves in the California Current Large Marine Ecosystem and broader northeast Pacific Ocean. Climate extremes from 2013–2021 have contributed to extreme bottlenecks in West Coast salmon survival rates for multiple West Coast salmon populations and subsequent declines in abundance for many DPSs and ESUs.  (p. 6)

Comment:  While poor ocean conditions may have been a major part of the problem in 2008-2009, this was not the case in the 2013-2021 period, at least in terms of the Central Valley salmon.  NMFS needs to look closer to home to address the causes and solutions to the Central Valley salmon collapse.