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

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 11, 74% 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.

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 28 and Jan 08 is 168 individuals. Total catch at Sacramento Trawl and Beach Seines in the delta between Dec 29 and Jan 08 is 19 individuals. Total catch at Delta Exit at Chipps Island between Dec 29 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 11, 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.

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 10, overall through delta STARS estimated survival probability (with 80% credible intervals) is 0.72 (0.64-0.8) placing it in the 93rd 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 0.04 (0.03-0.05) and 0.74 (0.62-0.85), respectively, corresponding to the 4th and 93rd percentiles of historical January estimates (WYs 2018-2025).

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.

Current Status

Delta Entry Timing - Historically, as of Jan 11, 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.

Delta Monitoring - Total catch of LAD winter run at RSTs at Delta Entry (Tisdale, Knights Landing, Lower Sacramento River) between Dec 28 and Jan 08 is 0 individuals. Total catch at Sacramento Trawl and Beach Seines in the delta between Dec 29 and Jan 08 is 0 individuals. Total catch at Delta Exit at Chipps Island between Dec 29 and Jan 08 is 0 individuals.

Annual Loss

As of January 11, cumulative loss of unclipped steelhead is 17.93 or 0.34% of the incidental take limit in the NMFS Biological Opinion. Cumulative loss in the past 7 days has been 74.83.

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.

Total loss of hatchery-origin steelhead is 96.59 or 2.71% 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.

Current Status

Delta Entry Timing- Historically, as of Jan 11, 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.

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 28 and Jan 08 is 137 individuals. Total catch at Sacramento Trawl and Beach Seines in the delta between Dec 29 and Jan 08 is 0 individuals. Total catch at Delta Exit at Chipps Island between Dec 29 and Jan 08 is 0 individuals.

Surrogate Releases

A total of 193,101 yearling surrogate fish have been released across 3 releases and a total of 0 young-of-year surrogate fish have been released across 0 releases. See details in table below.