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

Other Formats:   PDF   Word
With Hydrology:   PDF   Word
All Combined:   PDF   Word

on this page

Assessment for Delta Operations on Salmonids

Final: Tuesday, January 13, 2026 at 4 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, 122.07 (3.42% of threshold) Hatchery Steelhead, and 872.69 (10.84% of threshold) Spring-run Surrogates.

  • Winter-run presence in the Delta is high (historical peak).

  • Steelhead presence in the Delta is increasing.

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 12, 75% 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 0% 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% 78% 75% 38% 2% 15%
Chinook, DNA Winter-run, Unclipped (Water Year) NA NA NA NA NA 0%

Red Bluff Diversion Dam Passage Estimate - As of Dec 16 estimated passage to date of LAD winter run at Red Bluff Diversion is approximately 3.61 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 Dec 30 and Jan 12 is 190 individuals. Total catch at Sacramento Trawl and Beach Seines in the delta between Dec 30 and Jan 12 is 15 individuals. Total catch at Delta Exit at Chipps Island between Dec 30 and Jan 08 is 1 individuals.

Annual Loss

The annual Loss threshold for natural winter-run is 1% of the jpe or 10,574.52 fish. As of January 12, 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 12, overall through delta STARS estimated survival probability (with 80% credible intervals) is 0.73 (0.66-0.8) placing it in the 94th 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 0.09 (0.08-0.11) and 0.61 (0.45-0.76), respectively, corresponding to the 6th and 90th 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 12, 16% of CCV steelhead have entered the delta based on Knights Landing RST catch, 1% have exited the delta based on Chipps Island Trawl Catch, and 6% 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% 15% 16% 0% 1% 6%

Delta Monitoring - Total catch of LAD winter run at RSTs at Delta Entry (Tisdale, Knights Landing, Lower Sacramento River) between Dec 30 and Jan 12 is 0 individuals. Total catch at Sacramento Trawl and Beach Seines in the delta between Dec 30 and Jan 12 is 0 individuals. Total catch at Delta Exit at Chipps Island between Dec 30 and Jan 08 is 0 individuals.

Annual Loss

As of January 12, 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 97.59.

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 2 releases totaling 878,848 steelhead in Water Year 2026. JPE for the hatchery releases as of today is 356,526 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 3565, but is subject to change with additional steelhead releases.

Table 3: Summary of steelhead hatchery releases in Water Year 2026
Hatchery Date of Release Mean Fork Length (mm) Number Released Estimated Survival Juvenile Production Estimate
Nimbus 2025-11-02 223 233,109 72% 167,838
Coleman 2025-12-19 195 645,739 29% 188,688

Total loss of hatchery-origin steelhead is 122.07 or 3.42% 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 12, 26% 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 12% 14% 26% 2% 0% 0%

Red Bluff Diversion Dam Passage Estimate - As of Dec 16 estimated passage to date of LAD spring run at Red Bluff Diversion is approximately 0.01 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 Dec 30 and Jan 12 is 172 individuals. Total catch at Sacramento Trawl and Beach Seines in the delta between Dec 30 and Jan 12 is 0 individuals. Total catch at Delta Exit at Chipps Island between Dec 30 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. See details in table below.

Table 5: Spring-run Chinook Salmon Surrogate Releases.
Hatchery Release Date Type # of CWT Fish Released Confirmed Loss CWT Codes
Coleman NFH 2025-11-13 Yearling 143346 8.7 056808, 056809
Coleman NFH 2025-11-17 Yearling 75119 0.0 056810
Coleman NFH 2025-12-17 Yearling 468876 639.9 053700, 056806, 056811, 056812, 056814, 056815, 056817
Coleman NFH 2025-12-22 Yearling 60873 224.1 056813
Coleman NFH 2026-01-08 Yearling 57109 0.0 056816

Annual Loss

The annual loss threshold is 1% of the total releases, which equals 8,053 fish. As of January 12, cumulative loss is 872.69 fish or 10.84% 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 10.8% 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 3.4% of the threshold. Current trajectory suggests the threshold is unlikely to be exceeded in the upcoming week.