University of Washington

Track-a-Cohort -- Steelhead

Provides in-season, real-time data in comparison to data in historical years. Post-season, Track-a-Cohort also provides the latest annual data summaries.

Juveniles in River

Migration Timing — annual data

Today Percent

Average Percent by 11/13, with 95%CI, of annual emigrating population for juveniles of each species of interest captured at the following locations and salvaged at SWP and CVP Delta facilities
Species Red Bluff Diversion Dam Tisdale RST Knights Landing RST Sac Trawl (Sherwood) Catch Index Chipps Island Trawl Catch Index Salvage
Steelhead, Unclipped (January-December)            
Steelhead, Unclipped (Water Year)           0.3%
(-0.3%,0.9%)
WY: 2017 - 2026
Calculations generated by SacPAS Migration Timing and Conditions by Cohort and Salvage Timing. Data Courtesy of USFWS, Red Bluff; CDFW via StreamNet and CDEC; USFWS, Lodi.

Current Catch

Juveniles in Delta

Salvage Timing — annual data

Historical salvage timing for Unclipped Steelhead
Historical salvage timing for Clipped Steelhead

Delta STARS Survival and Routing Probabilities

Winter-run Chinook presented as surrogate for Steelhead

Winter-run Chinook as surrogate for Steelhead
Winter-run Chinook as surrogate for Steelhead
Winter-run Chinook as surrogate for Steelhead

Total Loss — Clipped and Unclipped Steelhead

Size (Fork Length) Distribution of Steelhead Loss, Combined

Figure compares density plots that highlight historical (WY1994 to WY2023) size distribution and histogram of current year (WY2024) size distribution by rear type (yellow = unclipped; blue = clipped). Fork lengths below 750 mm were included in dataset.

WY Size (Fork Length) Distribution of Steelhead Loss

Cumulative Loss by BiOp Status and Hydrologic Classification Index

The figure shows cumulative loss by BiOp Status and Hydrological Classification Index (HCI). Each quadrant of the faceted plot includes grey lines for historical years, colored lines (blue for wet years, red for dry years) for years within the BiOp status and HCI type, a black line for the current year, and a dashed horizontal line indicating the current cumulative loss maximum.

Loss Single Year Thresholds

Included from Salmonids, Steelhead, and Current Conditions for the Delta Actions Team (DAT), Workgroups & Teams.

graph Natural Central Valley Steelhead with WY2009-2018 history
Natural Central Valley Steelhead Loss Cumulative to Date with Historical Loss and Single Year Loss Thresholds
line graph loss Hatchery Central Valley Steelhead
Hatchery Central Valley Steelhead Loss Cumulative to Date

Minimization of Loss

Annual loss of clipped juvenile steelhead at the salvage facilities and total hatchery juvenile steelhead release numbers. Coleman NFH releases from USFWS, CDFW hatchery releases available from calfish.org, salvage from Fish Salvage Monitoring, CDFW Bay Delta Region, and loss calculated by SacPAS.
Water Year (WY)Brood Year (BY)Total Hatchery Steelhead Releases (BY)Loss of clipped steelhead at the facilities (WY)% Loss of Total Hatchery Releases
2026202513980651898.370.136
2025202411219442532.140.226
2024202316345662850.320.174
2023202216497953655.740.222
202220211921199639.790.033
202120201861923341.690.018
202020191814005659.440.036
2019201817333085777.700.333
2018201711752202462.900.210
201720161123732164.290.015
2016201511575383566.870.308
2015201419892411841.190.093
201420131869840327.830.018
2013201215828501901.950.120
2012201117822731141.160.064
2011201012372762823.070.228
2010200914771376548.280.443
2009200814183512439.110.172
2008200720850256558.860.315
2007200619279574173.840.216
2006200516444332758.540.168
2005200419760136661.860.337
20042003141344618643.981.319
20032002172065324077.481.399
2002200110938815957.450.545
20012000115285424779.832.149
2000199986376318795.422.176
19991998969822555.640.057
19981997954247496.440.052
199719961174344.330.004
19961995930462330.740.036
199519941276130146.720.011
199419931327884125.250.009
1993199214169431576.950.111

Daily Loss and Export with OMR

Predicted Weekly Loss

Predicted and Observed Weekly Loss — Tillotson Model

The model is rerun with the addition of near-real-time data for new predictions as the season progresses. With each model run, the values for the historical estimates and confidence intervals are not identical due to randomization in the randomForest R function, but are statistically equivalent.

Table of Tillotson et al., (2022) model output of predicted weekly losses for Natural-origin Steelhead with model weekly average inputs including observed loss, Old and Middle Rivers (OMR), USGS tidally filtered flow (CFS), combined exports from CVP and SWP facilities (CFS), flow at Sacramento and San Joaquin (CFS), and water temperature at Mallard Island (°C).
WY weekDateMedian weekly predicted loss [lower CI, upper CI]Observed Data
Observed lossOMR USGS tidally filtered (CFS)Export, SWP & CVP (CFS)Avg flow at Sacramento (CFS)Avg flow at San Joaquin (CFS)Avg water temperature at Mallard Island (°C)
62026-11-050.0 [0.0, 2.7]0.0-2115.02162.07588.51203.116.5
52026-10-290.0 [0.0, 5.4]0.0-2397.11788.67878.61797.716.9
42026-10-220.0 [0.0, 17.3]0.0-2799.11935.47919.82109.917.9
32026-10-150.0 [0.0, 17.3]0.0-4022.93359.79098.81722.518.9
22026-10-080.0 [0.0, 0.1]0.0-6565.75522.011201.51132.819.9
12026-10-010.0 [0.0, 17.3]0.0-9857.19459.915102.91006.520.4

Adults in Ocean

CWT Smolt-to-Adult — annual data

Adults in River

No data sets or products to offer at this time.