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

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:

  1. Recognize and acknowledge the problem (we haven’t)
  2. Develop a single integrated, comprehensive plan to solve it (there isn’t one)
  3. 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)
  4. 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)
  5. 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)
  6. Overhaul the Central Valley water quality management system (drought “emergencies” routinely bring weakening of standards, wiping out annual salmon runs)
  7. 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).
  8. 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.

Graph of Adult Escapement (fish/year) Mainstem, Upstream of RBDD, Sacramento River, spawn years 1970-2021 In-River Winter Chinook

Figure 1. Sacramento River Winter-Run Chinook

Graph of Adult Escapement (fish/year) Mainstem, Upstream of RBDD, Sacramento River, spawn years 1969-2021, In-River Spring Chinook

Figure 2. Sacramento River Spring-Run Chinook

Graph of Adult Escapement (fish/year) Mainstem, Keswick Dam to Red Bluff Diversion Dam spawn years 1952-2021, In-Rier Fall Chinook

Figure 3. Sacramento River FallRun Chinook

Graph of Adult Escapement (fish/year) Mainstem, Upstream of RBDD, Sacramento River, spawn years 1971-2021, In-River Late-Fall Chinook

Figure 4. Sacramento River Late-Fall-Run Chinook


How did Winter-Run Salmon do in Summer 2022? Not Good.

First the bad news. The production in 2022 of winter-run salmon fry in the upper Sacramento River near Redding was at record low levels, similar to the disaster years 2014 and 2015, maybe worse (Figure 1).

Next, more bad news (there is no good news). Most of the fry are now in the 100-mile reach below Red Bluff, with only a small proportion to date (November 7) reaching Knights Landing below Chico (Figure 2). Flows (Figure 3) remain too low for good fry survival, with little flow increase following late October and early November rains. Clear water conditions make it easy for the tens of thousands of striped bass and smallmouth bass residing in the 100-mile reach to pick off migrating juvenile salmon. Up till late October, water temperatures above 60ºF kept bass active (also Figure 3). With conditions expected to be similar to last year, one can only expect this year’s production to be similar to last year’s poor production (Figure 4).

Some might say increased hatchery winter run production in 2022 is good news. Higher than normal numbers of hatchery fry are being raised in the Livingston-Stone Fish Hatchery for release next winter. But last winter’s hatchery releases during critical drought conditions did not fare well, as shown by the very small numbers that reached the Delta (Figure 5). To compensate, Interior began increasing egg-taking1 for the hatchery and transporting adults and hatchery smolts to upper reaches of Battle Creek. While these actions are worthwhile, the problem remains that drought year release returns (harvest plus escapement) average about 0.2%, compared to 2% returns in wet years.2

The prognosis for the winter-run salmon from all these sources of recruitment during the 2020-2022 drought to return as adults into fishery catches and the spawning runs is grim.3 The population does recover after wetter year periods (2016-2019, Figure 6), but not without the support of the hatchery. More needs to be done to improve wild and hatchery fry survival and smolt production to safely recover the winter-run salmon population. Flow pulses and enforcement of the state water temperature standards are needed. Vitamin injections, more hatchery egg-taking, and taxi rides alone will not do the job.

Graph showing Run Size from 2007 through 2022

Figure 1. Annual catch of unmarked juvenile winter run salmon in screw traps near Red Bluff as of November 13, 2022. (Source)

Graphs showing Water Temperature and Daily Estimated Passage

Figure 2. Juvenile winter-run salmon catch in Red Bluff and Colusa screw traps in 2022. (Source)

Graph showing flow CFS and Temp

Figure 3. Water temperature and flow rate below Keswick Dam (KWK, RM 300), at Bend near Red Bluff (BND, RM 250), and below Wilkins Slough (WLK, RM 120) in 2022. (Source)

Graph of Cumulative Catch per Brood Year

Figure 4. Annual catch of unmarked juvenile winter run salmon in screw Chipps Island trawls near Pittsburg, CA. Red arrow shows 2021 catch. (Source)

Graph of Observed Chinook Salvage at SWP and CVP Delta Fish Facilities

Figure 5. Salmon salvage at south Delta export facilities in 2021. Salvage of hatchery release groups is color coded. Red arrow shows winter-run hatchery smolt release group and the subsequent capture/salvage of two smolts from the group in late March. (Source)

Graph California Central Valley Population Database Report CDFW GrandTab Adult Escapement

Figure 6. Winter run salmon escapement 1970-2021. (Source)