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

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Assessment for Delta Operations on Salmonids

Final: Tuesday, January 20, 2026 at 3 PM

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, 43.91 (0.83% of threshold) Natural Steelhead, 148.05 (2.5% of threshold) Hatchery Steelhead, and 992.49 (45.14% 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

Entry Timing - Historically, as of Jan 19, 78% 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
Species Red Bluff Diversion Dam Tisdale RST Knights Landing RST Sac Trawl (Sherwood) Chipps Island Trawl Salvage
Chinook, LAD Winter-run, Unclipped 98% 84% 78% 42% 2% 19%
Chinook, DNA Winter-run, Unclipped (Water Year) NA NA NA NA NA 2%

Red Bluff Diversion Dam Passage Estimate - As of Dec 31 estimated passage to date of LAD winter run at Red Bluff Diversion is approximately 4.16 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 06 and Jan 12 is 129 individuals. Total catch at Sacramento Trawl and Beach Seines in the delta between Jan 07 and Jan 16 is 3 individuals. Total catch at Delta Exit at Chipps Island between Jan 06 and Jan 08 is 0 individuals.

Annual Loss

The annual Loss threshold for natural winter-run is 1% of the jpe or 10,574.52 fish. As of January 19, 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 19, overall through delta STARS estimated survival probability (with 80% credible intervals) is 0.65 (0.59-0.71) placing it in the 80th 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 (0.1-0.13) and 0.38 (0.23-0.53), respectively, corresponding to the 23rd and 77th 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 simulate 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 for Livingston Stone releases.

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 19, 26% of CCV steelhead have entered the delta based on Knights Landing RST catch, 2% have exited the delta based on Chipps Island Trawl Catch, and 7% have been salvaged.

Table 2: Average Percent of annual emigrating population for unclipped CCV steelhead captured at the following locations and salvaged at SWP and CVP 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% 20% 26% 2% 2% 7%

Delta Monitoring - Total catch of LAD winter run at RSTs at Delta Entry (Tisdale, Knights Landing, Lower Sacramento River) between Jan 06 and Jan 12 is 0 individuals. Total catch at Sacramento Trawl and Beach Seines in the delta between Jan 07 and Jan 16 is 0 individuals. Total catch at Delta Exit at Chipps Island between Jan 06 and Jan 08 is 0 individuals.

Annual Loss

As of January 19, cumulative loss of unclipped steelhead is 43.91 or 0.83% of the incidental take limit in the NMFS Biological Opinion. Cumulative loss in the past 7 days has been 25.98.

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 5914, but is subject to change with additional steelhead releases.

Table 3: Summary of steelhead hatchery releases in Water Year 2026
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

Total loss of hatchery-origin steelhead is 148.05 or 2.5% of the 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

Current Status

Delta Entry Timing- Historically, as of Jan 19, 27% 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 4: Average Percent of annual emigrating population for LAD Spring-run Chinook Salmon captured at the following locations and salvaged at SWP and CVP 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 13% 16% 27% 2% 0% 0%

Red Bluff Diversion Dam Passage Estimate - As of Dec 31 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 06 and Jan 12 is 103 individuals. Total catch at Sacramento Trawl and Beach Seines in the delta between Jan 07 and Jan 16 is 0 individuals. Total catch at Delta Exit at Chipps Island between Jan 06 and Jan 08 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 5: 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 468,876 128,002 729.4 053700, 056806, 056811, 056812, 056814, 056815, 056817
Coleman NFH 2025-12-22 Experimental 60,873 16,618 254.4 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 19, cumulative loss is 992.49 fish or 45.14% 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 Single Year Loss Thresholds.
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 Single Year Loss Thresholds.
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 45.1% 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 2.5% of the threshold. Current trajectory suggests the threshold is unlikely to be exceeded in the upcoming week.