Sacramento River Salmon Harvest Forecast: More Bad News

Posted on March 1, 2023 by Tom Cannon

The harvest of Sacramento River fall-run salmon – the largest of California’s dwindling salmon runs – is managed by both state and federal agencies and is based on past-to-present figures of long-term adult escapement (i.e., fish that aren’t caught and survive to spawn) (Figure 1).

The harvest is coordinated under the Pacific Fishery Management Council (PFMC), because many of the ocean fisheries take mixed stocks from both the US states and Canadian provinces. The “fishable” Sacramento River fall-run population is defined as the total number of adults in the ocean and rivers available for harvest in the ocean and rivers. The harvestable stock is defined as adults. It does not include grilse (salmon returning to freshwater after a single season at sea), whose harvest is generally not allowed.

Chart showing past-to-present figures of long-term adult escapement

Figure 1

The PFMC has declared an adult salmon escapement of 122,000-180,000 as a target goal range, a figure that theoretically provides a sustained yield for the fishery. However, because escapement estimates are not made until the end of the fishery harvest, total escapement has usually fallen below the maintenance goal – especially during drought years or after multiyear droughts.

In some years, sanctioned harvests have led to over-fishing (e.g., 2007, Figure 2). This is because the harvest control rules the PFMC employ are often based on inaccurate estimates of the size of the harvestable stocks and the relative effectiveness of the fisheries – how good the fisheries are at catching salmon (very good, it turns out).

Together, these harvest model errors and biases have led to over-fishing. This is not a new problem. Excessive harvests contributed to closure of the ocean salmon fishery off California in 2008 and 2009.

The PFMC and its constituent states and provinces are now developing harvest control rules for the 2023 fisheries. For the Sacramento River fall-run population, the preliminary estimate of the 2023 harvestable stock is approximately 180,000 fish; accordingly, the PFMC is anticipating a sanctioned harvest, and is now preparing harvest control rules.

But it would be a grave mistake to authorize a 2023 Sacramento River fall-run harvest; there should be no harvest allowed this year. Why? There are multiple reasons.

First, the 2019 to 2022 population trend was decidedly downward (Figure 1), and the salmon stock was overharvested in 2021 and 2022. Also, water year 2021 was a critical drought year that led to poor survival of the 2020 brood year fish. Due to drought conditions, 2021 brood year salmon experienced poor spawning, incubating, rearing, and emigration conditions. As a result, the fishable brood year 2020 and 2021 stocks now in the ocean are likely small, and their return to their natal rivers will likely be minimal. Indeed, the return (escapement) numbers for the 2020 brood year fish could be even lower than those for 2009, 2017, or 2022 – all abysmal years for returning salmon.

The bottom line: prospects for recovering a wild or natural-born salmon population in the Sacramento River and its tributaries will be substantially diminished if a salmon fishery is allowed in California this year.

Chart of the Sacramento Index and relative levels of its components.

Figure 2. Note harvest in 2007 and 2015-2017 resulted in failure to meet escapement goal of 122,000 adult salmon.

Table of the performance of Chinook salmon stocks in relation to 2022 preseason conservation objectives.

Figure 3. There was a fishery in 2022. Note 60,000 escapement for 2022 was only a third of the target goal of 180,000.

Smelt Status – Winter 2023 How Low Can You Go?

Posted on February 19, 2023 by Tom Cannon

In prior posts in December 2022 and November 2021, I described the status of listed delta smelt and of longfin smelt. More recent information shows little change in the dire outlook for these two native Bay-Delta fish (Figures 1-4).

Delta smelt and longfin smelt populations have declined severely over the past few decades due to poor water management. In the Bay-Delta, where the smelt spend most of their lives, south Delta water exports and warming of the Bay and Delta from reduced inflow and outflow has limited their production. Temporary urgency change petitions (TUCPs) during multiyear droughts and subsequent orders by the State Water Board have allowed reduced Delta outflow, leading to higher water temperatures and increased Delta salinity. The State Board is again considering yet another TUCP in winter 2023 that would reduce Delta outflow to allow higher exports.

In this winter 2023, the Low Salinity Zone has again moved further upstream (eastward) into the Delta because of falling freshwater inflow to the Delta after the January storms. Delta exports have fallen with lower Delta inflows as State Board conditions kick in. The TUCPs are an obvious and direct threat to these population remnants living in the Low Salinity Zone. Further allowing these weakened standards to be violated is a direct disregard for these nearly extinct species. Water management places them at extraordinary risk by (1) bringing them further into the Central-Delta zone of the two large South-Delta water diversions, (2) degrading smelt habitat with lethal water temperature, (3) further degrading their already depleted food supply, and (4) increasing the concentrations of toxic chemicals being relentlessly discharged into the Delta.

The scientific literature, and water and resource management agencies, all recognize these major problems. Many management and recovery schemes have been developed and implemented over the decades. However, nothing has stopped water managers’ relentless excessive use and abuse of the Central Valley hydrology. The salmon, smelt, sturgeon, and steelhead are not just the victims but serve as “canaries in a coal mine”, all dying while the water is continually mined from the system. Meanwhile, water managers blamed this mass extinction event on on climate change, cynically gaming worsening conditions to extract even more water.

There is more and more talk of employing “ecosystem-based management” that integrates the environment into all phases of decision-making, effectively giving the environment a seat at the table. But the reality is more like giving the chickens a say in how the foxes manage the depopulation of the hen-house. There is also talk about providing more flexibility in how and when water is used – allocating environmental water as “functional flows” or “environmental water storage” to optimize the ecosystem benefits of what little water is allocated for the environment. Placed in he hands of water managers, such efforts simply give them more flexibility to game the system to their advantage. When they think they can get more water, they just ask for it and usually get it. One policy group proposes: “Making this work may require establishing assets for the environment—such as water budgets, reservoir storage space, and funding to restore physical habitat—that can be flexibly used to adapt to changing conditions.” No, a piece of bread and a cup of water on the survivors’ deathbeds are all they get. Even the water managers get to choose the physical habitat and how its restored, and how much extra water they can take as a result.

It is time to change this pattern of abuse of public trust resources by standing up to abusers in the State’s TUCPs, the Update of the Bay-Delta Water Quality Control Plan, and the public review of the Delta Tunnel Project. The Tunnel simply adds another straw in the Delta, but further upstream, closer to the mouths of the Feather and American rivers, the main sources of Bay-Delta freshwater inflow.

Figure 1. Bay-Delta fall-midwater-trawl longfin smelt catch index 1967-2022.

Figure 2. Longfin Smelt Fall Midwater Trawl Index in recent two decades 2001-2022.

Figure 3. Log-Log relationship for longfin smelt index year (number shown are brood year “recruits”) vs index two years prior (spawners). Red numbers represent brood years that were the product of dry water years, green numbers = normal water years, and blue = wet water years. Blue dots are six most recent years, 2017-2022: fewer spawners produce fewer recruits.

Figure 4. Catch of Delta smelt in 20-mm Survey in late March 2022. Seven were captured in the north Delta just upstream of where adult hatchery smelt were released in December 2021.

Missing an Opportunity Downstream of Shasta Lake Late Fall – Early Winter Pulse Flow for Salmon Needed

Posted on January 2, 2023 by Tom Cannon

Juvenile winter-run, spring-run, fall-run, and late-fall-run salmon need a flow boost in the fall and winter to help them emigrate 300 miles down the Sacramento River from their spawning area below Shasta Lake to and through the Bay-Delta.¹ Yet while winter storms have now caused massive runoff downstream, the spawning reach of Sacramento River remains at its minimum flow. Even small pulse releases from Shasta and Keswick reservoirs during storms would start hundreds of thousands of juvenile salmon on their way to the ocean.

Historically, more than 50% of salmon spawning in the lower Sacramento River took place downstream of Clear Creek (Figure 1). That distribution has now changed, with over 90% of the spawning upstream of the mouth of Clear Creek in the 20 miles of river downstream of Keswick Dam. This change is a consequence of water management that confines suitable spawning habitat in summer and fall to the uppermost river reach.

Many juvenile salmon begin their migration to the ocean when the first fall rains create a pulse in streamflow. These fish include winter-run and late-fall-run smolts, and fall-run and spring-run fry. The first fall rain-induced flow pulse has been long recognized as an important functional flow event for all four salmon runs. For many decades, the fall pulse was recognized as an important feature needed in salmon management to ensure good survival of smolts to the ocean.

The fall pulse has often been forestalled in recent decades both by droughts and by water management. When the fall pulse comes, it comes only from upper river tributaries. But the natural salmon production cycle in the upper 20 miles of the spawning reach misses out on the flow benefit of fall rains. All runoff is captured in Shasta Reservoir. While downstream reaches receive tributary rainfall-induced streamflow (Figure 2), the upper river receives no pulse from Shasta Reservoir despite significant inflows (Figure 3). This factor alone is a key factor limiting natural production of the four salmon runs in the upper Sacramento River.

Lack of flow from Shasta also limits the effectiveness of the overall flow pulse (Figures 4 and 5) that carries the juvenile salmon downstream to the estuary. The upper Sacramento River, McCloud River, and Pit River flow into Shasta Lake. These major spring-fed rivers are the largest contributors of natural flows to the Sacramento River watershed, especially in drier years. They have not provided any the mainstem streamflow to the Bay-Delta estuary as yet this year. This pattern is generally true in all but the wettest water years.

Shasta Lake gained about 40,000 acre-feet in the first fall storm (Figure 6). A pulse flow of 5000 cfs for three days (an increase of approximately 2000 cfs for 72 hours) would have amounted to approximately 12,000 acre-feet, or roughly 30% of the water gained and (0.8% of the total storage). Considering that much of the first storm fell as snow, water managers could have reasonably have executed such a short pulse..

The second storm has delivered Shasta Reservoir another 100,000+ acre-feet. With a wet forecast for January, it is now time to release a least a short pulse from Shasta to move juvenile salmon downstream to where they can surf the tributary inflow to the Sacramento River downstream to the Delta. It is not too late. Before the storm that began December 29, most of the juvenile salmon remained upstream of Red Bluff or downstream in the river above the Delta,² as few had shown in Sacramento seines and trawls (data not shown).

Figure 1. Upper Sacramento River and historic salmon spawning distribution by percent by region. River-mile shown in parentheses. (Data source: CDFW)

Figure 2. Fall river flows at seven locations from Keswick Dam RM-300 (KWK), Bend RM-250 (BND), Hamilton City RM 200 (HMC), Colusa RM-144 (COL), Wilkins Slough RM-140 (WLK), Verona RM-80 (VON), and Freeport RM-50 (FPT) in the Delta.

Figure 3. Shasta Reservoir inflow and outflow in December 2022. (Data source: CDEC)

Figure 4. Screw-trap catch of fry spring-run and fall-run salmon with environmental data in fall 2022 at three locations in lower Sacramento River.

Figure 5. Screw-trap catch of winter-run fry-smolt salmon with environmental data in fall 2022 at three locations in lower Sacramento River.

Figure 6. Shasta Reservoir storage level in Nov-Dec 2022.

Central Valley Hatchery Salmon Production Is Being Wasted A Tale of Two Hatchery Salmon Smolt Release Groups

Posted on December 11, 2022 by Tom Cannon

There are two common strategies for releasing juvenile salmon from state and federal salmon hatcheries in the Central Valley. One strategy is the release of hatchery salmon smolts at or near the hatchery where they are produced. The other strategy is trucking the smolts from the hatchery and releasing them into the Bay. There is much controversy and argument over the relative merits of the strategies. There can be little argument that release into the Bay generates far more adult salmon than release near the hatcheries.

Consider what occurred with two American River release groups after their release in May 2018 and return as adults in 2020. Release group #061465 was 669,000 fall-run smolts (3-4 inches long) that were transported 20 miles downstream from the American River (Nimbus) Hatchery and released into the mouth of the American River under the Jibboom Street Bridge. Release group #061467 was 650,000 fall-run smolts transported approximately 100 miles downstream to net pens at the Wickland Oil Terminal for release into eastern San Pablo Bay, about 20 miles from the Golden Gate Bridge and the Pacific Ocean.

The estimated percent survival based on tag recoveries was 0.04% for group #061465 (released near the hatchery). The estimated percent survival was 2.20% for group #061467 (released in San Pablo Bay). The returns by locations are shown in Figures 1 and 2. These relative results are common.

Figure 1. Returns for tag group #061465.

Figure 2. Returns from tag group #061467.

The Demise of Sacramento River Spring-Run, Fall-Run, and Late-Fall-Run Chinook Salmon

Posted on November 18, 2022 by Tom Cannon

We all know the story of the demise of Sacramento River winter-run Chinook salmon below Shasta Dam over the past several decades (Figure 1).¹ But what has happened to the other three Chinook runs: the spring, fall, and late-fall runs? They too have declined (Figure 2-4). Just 50 years ago, 300-500 thousand Chinook salmon ascended the Sacramento River to spawn. This was decades after most of the big Central Valley dams were built. Today, less than 10,000 Chinook salmon return to spawn near Redding. Most of these are Battle Creek and Livingston Stone hatchery fish, plus strays from Feather, American, Mokelumne, and Merced hatcheries. Wild, native Chinook are becoming increasingly rare with each decade.

There are many factors that have led to the demise of Sacramento River Chinook salmon. No doubt, the two major droughts (76-77 and 87-92) had major roles. There was bad management and lack of regulatory protection on many levels. Today, the details of a post mortem are of less value than recognizing the problem and doing something about it.

Much has been tried and accomplished (three of the four runs substantially improved around the turn of the century). A decade of effort and wet years achieved much. However, the three major droughts since (07-09, 13-15, and 20-22) have undone much of those gains and more.

What needs to be done now to bring the salmon back from the brink of extinction is the following:

Recognize and acknowledge the problem (we haven’t)
Develop a single integrated, comprehensive plan to solve it (there isn’t one)
Overhaul the massive salmon hatchery program (we spend huge sums raising and releasing over 30 million salmon smolts each year – the price per pound is astounding – most never reach the ocean)
Overhaul our salmon fisheries program managed by the Pacific Fisheries Management Council (it’s not working – the stocks are in a constant state of over-fishing – and the fishery is not the most important problem – shutting fishery gates after fish have escaped the corral doesn’t solve the problem)
Overhaul the Central Valley water supply management system (it’s taking all the water for humans and leaving none for the salmon – don’t let folks blind you, it’s true)
Overhaul the Central Valley water quality management system (drought “emergencies” routinely bring weakening of standards, wiping out annual salmon runs)
Rebuild salmon habitat from the ground up (much is gone and what is left is degrading fast, as past and present efforts at watershed restoration literally burn away each year).
Implement the comprehensive plan with prioritized short- and long-term goals, objectives, and actions.

The sooner we implement these actions the better – Sacramento River salmon are facing a “Passenger Pigeon” moment. The longer we wait, the tougher it is going to be and the less chance there is we will succeed.