Winter Chinook, Steelhead, and Spring Chinook -- Delta Actions Team Real-time Assessments

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Assessment for Delta Operations on Salmonids

Last updated: Tuesday, January 27, 2026 at 8 AM

For more detailed data on salmonid conditions in the Delta see corresponding webpage on SacPAS.

Executive Summary

  • Entrainment management season is active.

  • Season Loss: 0 (0.00% of threshold) DNA Winter-run, 0 (0.00% of threshold) Hatchery Winter-run, 47 (0.88% of threshold) Natural Steelhead, 153 (2.59% of threshold) Hatchery Steelhead, and 1013 (46.08% of threshold) Spring-run Surrogates.

  • Winter-run presence in the Delta is decreasing (winding down).

  • Steelhead presence in the Delta is high (historical peak).

Natural Winter-run Chinook

Juvenile Production Estimate

The Juvenile Production Estimate for winter-run is 1,057,452 for the current water year.

Current Status

Delta Entry Timing - Historically, as of Jan 26, 82% of length-at-date (LAD) winter-run have entered the Delta based on Knights Landing RST catch, 2% have exited the Delta based on Chipps Island Trawl Catch, and 2% of DNA confirmed winter-run have been salvaged.

Table 1: Average percent of annual emigrating population for unclipped LAD winter-run captured at monitoring locations and salvaged at Delta facilities for the past 10 years

Species

Red Bluff Diversion Dam

Tisdale RST

Knights Landing RST

Sac Trawl (Sherwood)

Chipps Island Trawl

Salvage

Chinook, LAD Winter-run, Unclipped

99%

87%

82%

44%

2%

20%

Chinook, DNA Winter-run, Unclipped (Water Year)

2%

Red Bluff Diversion Dam Passage Estimate - As of Jan 21 estimated passage to date of LAD winter-run at Red Bluff Diversion is approximately 4.17 million fish. Note that outmigration timing overlaps with spring-run migrating fish, and true winter-run abundance likely differs from these estimates.

Delta Monitoring - Total catch of LAD winter run at RSTs at Delta Entry (Tisdale, Knights Landing, Lower Sacramento River) between Jan 12 and Jan 22 is 63 individuals. Total catch at Sacramento Trawl and Beach Seines in the delta between Jan 12 and Jan 23 is 3 individuals. Total catch at Delta Exit at Chipps Island between Jan 20 and Jan 22 is 0 individuals.

Annual Loss

The annual Loss threshold for natural winter-run is 1% of the jpe or 10,575 fish. As of January 26, cumulative loss of genetically confirmed winter-run is 0 or 0.00% of the annual loss threshold. Cumulative loss in the past 7 days has been 0.

Line chart of cumulative loss of natural-origin winter-run Chinook salmon at Delta facilities where daily loss is tracked against the annual threshold
Figure 1: Cumulative loss of natural-origin winter-run for WY 2026. Cumulative loss is based on genetically confirmed winter-run captured in salvage or length-at-date winter-run in which genetic confirmation was unable to be obtained

STARS

The Delta STARS Model is an individual-based simulation model that predicts survival, travel time, and routing of juvenile salmon migrating through the Sacramento–San Joaquin River Delta. This model gives insight into survival and routing patterns of winter-run based on most current conditions.

As of January 25, overall through delta STARS estimated survival probability (with 80% credible intervals) is 0.57 (0.5-0.64) placing it in the 71st percentile of historical STARS survival estimates for the month of January (WYs 2018-2025). STARS estimated routing and survival probabilities (with 80% credible intervals) into the interior delta are 0.12 (0.1-0.14) and 0.27 (0.13-0.42), respectively, corresponding to the 32nd and 69th percentiles of historical January estimates (WYs 2018-2025).

Line chart of estimated overall winter-run survival probability from Knights Landing to Chipps Island where the current water year is compared to historical years
Figure 2: Estimated overall winter-run survival from Knights Landing to Chipps Island. Black line indicates the current water-year, and other colored lines correspond to past water years
Line chart of winter-run survival probability through the interior Delta where the current water year is compared to historical years
Figure 3: Estimated survival from Knights Landing to Chipps Island of simulated winter-run cohorts that route through the interior Delta. Black line indicates the current water-year, and other colored lines correspond to past water years
Line chart of winter-run routing probability into the interior Delta where the current water year is compared to historical years
Figure 4: Estimated probability of winter-run routing into the interior Delta. Black line indicates the current water-year, and other colored lines correspond to past water years

Hatchery Winter-run Chinook

Hatchery Releases

To date, no winter-run Livingstone hatchery releases have occurred in WY 2026

Juvenile Production Estimate

The Juvenile Production Estimate for hatchery winter-run is 130,096 based on current Livingston Stone production estimates. Note: Physical releases have not yet occurred in WY 2026.

Annual Loss

To date, no loss has occurred as no hatchery winter-run have been released.

Natural-origin Central Valley Steelhead

Current Status

Delta Entry Timing - Historically, as of Jan 26, 32% of CCV steelhead have entered the Delta based on Knights Landing RST catch, 4% have exited the Delta based on Chipps Island Trawl Catch, and 9% have been salvaged.

Table 2: Average percent of annual emigrating population for unclipped CCV steelhead captured at monitoring locations and salvaged at Delta facilities for the past 10 years

Species

Red Bluff Diversion Dam

Tisdale RST

Knights Landing RST

Sac Trawl (Sherwood)

Chipps Island Trawl

Salvage

Steelhead, Unclipped

1%

21%

32%

3%

4%

9%

Delta Monitoring - Total catch of LAD winter run at RSTs at Delta Entry (Tisdale, Knights Landing, Lower Sacramento River) between Jan 12 and Jan 22 is 3 individuals. Total catch at Sacramento Trawl and Beach Seines in the delta between Jan 12 and Jan 23 is 0 individuals. Total catch at Delta Exit at Chipps Island between Jan 20 and Jan 22 is 0 individuals.

Annual Loss

As of January 26, cumulative loss of unclipped steelhead is 47 or 0.88% of the annual loss threshold. Cumulative loss in the past 7 days has been 5.

Line chart of cumulative loss of natural-origin steelhead at Delta facilities where daily loss is tracked against the annual threshold
Figure 5: Cumulative loss of natural-origin steelhead for WY 2026

Hatchery-origin Central Valley Steelhead

Surrogate Releases

There have been a total of 5 releases totaling 1,373,848 steelhead in Water Year 2026. JPE for the hatchery releases as of today is 591,419 based on estimated survivals using forecasted water year types (see details in table below). The annual loss threshold, equal to 1% of the JPE, is currently 5,914, but is subject to change with additional steelhead releases.

Table 3: Summary of steelhead hatchery releases in Water Year 2026. JPE calculated using hatchery-specific survival estimates to Delta entry from release location

Hatchery

Date of Release

Number Released

Estimated Survival

Juvenile Production Estimate

NIM

2025-11-10

233,109

72%

167,838

Coleman

2025-12-15

555,720

38%

211,174

Coleman

2025-12-17

90,019

38%

34,207

FRH

2026-01-06

371,250

36%

133,650

FRH

2026-01-09

123,750

36%

44,550

Table 4: Hatchery-specific survival estimates used for JPE calculations

Hatchery

Survival Estimate

Source

Coleman NFH

0.205 – 0.433

Sandstrom et al. 2020

Feather River Hatchery

0.09 – 0.45

Kurth 2013

Nimbus Hatchery

0.62 – 0.83

Brodsky et al. 2020

Mokelumne River Hatchery

0.25 – 0.33

Del Real et al. 2012

Total loss of hatchery-origin steelhead is 153 or 2.59% of the annual loss threshold. Note that hatchery origin of salvaged fish can not be determined at this time and salvage is based on the assumption of similar routing and survival probabilities of individual hatchery releases.

Line chart of cumulative loss of hatchery-origin steelhead at Delta facilities where daily loss is tracked against the annual threshold
Figure 6: Cumulative loss of hatchery steelhead for WY 2026

Spring-run Chinook

Current Status

Delta Entry Timing - Historically, as of Jan 26, 28% of LAD spring-run have entered the Delta based on Knights Landing RST catch, 0% have exited the Delta based on Chipps Island Trawl Catch, and 0% have been salvaged.

Table 5: Average percent of annual emigrating population for LAD spring-run Chinook salmon captured at monitoring locations and salvaged at Delta facilities for the past 10 years

Species

Red Bluff Diversion Dam

Tisdale RST

Knights Landing RST

Sac Trawl (Sherwood)

Chipps Island Trawl

Salvage

Chinook, LAD Spring-run, Unclipped

14%

16%

28%

2%

0%

0%

Red Bluff Diversion Dam Passage Estimate - As of Jan 21 estimated passage to date of LAD spring-run at Red Bluff Diversion is approximately 0.02 million fish. Note that outmigration timing overlaps with winter-run and fall-run outmigration, and true spring-run abundance likely differs from these estimates.

Delta Monitoring - Total catch of LAD winter run at RSTs at Delta Entry (Tisdale, Knights Landing, Lower Sacramento River) between Jan 12 and Jan 22 is 161 individuals. Total catch at Sacramento Trawl and Beach Seines in the delta between Jan 12 and Jan 23 is 0 individuals. Total catch at Delta Exit at Chipps Island between Jan 20 and Jan 22 is 0 individuals.

Spring-run Surrogate Releases

A total of 805,323 spring-run surrogate fish have been released in Water Year 2026, with an estimated Juvenile Production Estimate (JPE) of 219,852 fish entering the Delta. This includes 805,323 Coleman Late-Fall Run Chinook (JPE: 219,852) released from Coleman National Fish Hatchery across 12 coded-wire tag groups. See details in table below.

Table 6: Spring-run Chinook salmon surrogate releases (all Coleman Late-Fall releases, both production and experimental)

Hatchery

Release Date

Type

# of CWT Fish Released

JPE

Confirmed Loss

CWT Codes

Coleman NFH

2025-11-13

Production

143,346

39,134

8.7

056808, 056809

Coleman NFH

2025-11-17

Experimental

75,119

20,507

0.0

056810

Coleman NFH

2025-12-17

Production

468,876

128,002

747.0

053700, 056806, 056811, 056812, 056814, 056815, 056817

Coleman NFH

2025-12-22

Experimental

60,873

16,618

257.3

056813

Coleman NFH

2026-01-08

Experimental

57,109

15,591

0.0

056816

Annual Loss

The annual loss threshold is 1% of the JPE entering the Delta, which equals 2,199 fish. As of January 26, cumulative loss is 1,013 fish or 46.08% of the annual loss threshold.

Loss Prediction and Trajectories

The following figures display the cumulative loss trajectories relative to historical years (“Spaghetti Plots”) and the current loss predictor model outputs for winter-run Chinook salmon and steelhead.

Line chart showing cumulative loss of natural LAD winter-run Chinook salmon for the current water year (black line) compared to historical years (gray lines) with annual loss threshold indicated as a horizontal dashed line
Figure 7: Natural LAD winter-run Chinook salmon loss cumulative to date with historical years and annual loss threshold
Line chart showing cumulative loss of natural Central Valley steelhead for the current water year (black line) compared to historical years (gray lines) with annual loss threshold indicated as a horizontal dashed line
Figure 8: Natural Central Valley steelhead loss cumulative to date with historical years and annual loss threshold
Graph showing observed cumulative loss of winter-run Chinook salmon (points) with predicted future loss trajectories including mean predictions (line) and 80% credible intervals (shaded area)
Figure 9: Estimates of winter-run Chinook loss generated by Loss and Salvage Predictor tool
Graph showing observed cumulative loss of steelhead (points) with predicted future loss trajectories including mean predictions (line) and 80% credible intervals (shaded area)
Figure 10: Estimates of steelhead loss generated by Loss and Salvage Predictor tool

Evaluation

  1. What is the probability of exceeding natural or hatchery winter-run Chinook salmon loss thresholds in the upcoming week?

    LOW RISK: Cumulative loss is currently 0% of the threshold. Current trajectory suggests the threshold is unlikely to be exceeded in the upcoming week.

  2. What is the probability of spring-run hatchery Chinook salmon loss thresholds in the upcoming week?

    LOW RISK: Cumulative loss is currently 46.1% of the threshold. Current trajectory suggests the threshold is unlikely to be exceeded in the upcoming week.

  3. What is the probability of hatchery steelhead loss thresholds in the upcoming week?

    LOW RISK: Cumulative loss is currently 2.6% of the threshold. Current trajectory suggests the threshold is unlikely to be exceeded in the upcoming week.

References

Brodsky, Annie, Steven C. Zeug, Jonathan Nelson, John Hannon, Paul J. Anders, and Bradley J. Cavallo. “Does Broodstock Source Affect Post-Release Survival of Steelhead? Implications of Replacing a Non-Native Hatchery Stock for Recovery.” Environmental Biology of Fishes 103, no. 5 (2020): 437–53. https://doi.org/10.1007/s10641-020-00951-2.

Del Real, S. Casey, Michelle Workman, and Joseph Merz. “Migration Characteristics of Hatchery and Natural-Origin Oncorhynchus Mykiss from the Lower Mokelumne River, California.” Environmental Biology of Fishes 94, no. 2 (2012): 363–75. https://doi.org/10.1007/s10641-011-9967-z.

Kurth, R. 2013. Downstream migration success of Feather River Fish Hatchery steelhead smolts under different release strategies. Presentation at Steelhead Management Meeting, California Department of Fish and Wildlife.

Sandstrom, Philip Thomas, Arnold J. Ammann, Cyril Michel, et al. “Low River Survival of Juvenile Steelhead in the Sacramento River Watershed.” Environmental Biology of Fishes 103, no. 5 (2020): 531–41. https://doi.org/10.1007/s10641-020-00954-z.