DART PIT Tag Adult Fish Ladders Fallback

Data Courtesy of Pacific States Marine Fisheries Commission

PIT Tag Adult Return Queries

Select Year, Adult Fish Ladder, Species, Run, Rear Type

The year following the project indicates earliest analysis available.

Release Site (Primary)

Exclude or include fish released below the selected Project.

Release Region (Secondary)

Exclude or include fish based on release region: Snake, Columbia above Snake Confluence, or Mainstem. Applied after restrictions on "Release Site".

Tagged in Year

Exclude or include fish tagged in year. Fish tagged in year are most likely handled in same year as ascent analysis. Fish tagged in year may include minijacks and fish tagged as adults.


Exclude or include Transported fish as determined by the DART Transportation Filter.

We are no longer maintaining the DART PIT Tag Adult Fallback Adjustment Rates analysis product; results are available by request. This is a new analysis product with new methods, not a revision. Please submit your questions, comments, and ideas to web@cbr.washington.edu. Thank you.

Methods and Query Notes

New analysis process implemented August 2017.

Adult PIT Tag Data for Analysis

On a daily basis, DART retrieves and uploads release and detection updates from PTAGIS. DART has developed a Life Stage Filter, ESU/DPS Filter, and Transportation Filter that are applied to all releases and detections. Based on DART categorizations of PIT Tagged fish and user-selections, a list of qualifying Tag IDs at the selected Adult Fish Ladder Project is generated and the full detection history is generated for ascent and attempt analysis. Required: categorized as "adult" detection by DART and not released in the same calendar year as detection. Release year exception: if included by user, fish tagged at BONAFF, Bonneville Adult Fish Facility or LGRLDR, Lower Granite Fish Ladder.

Site Configurations

Adult Fish Ladder site configurations are based on information retrieved daily from PTAGIS and converted into the CBR Site Configuration file used by multiple analysis programs.

At this time, the ascent and fallback analysis covers the site configurations for:

  • Bonneville (BO1, BO2, BO3, BO4) 2006 to present
  • McNary (MC1, MC2) 2006 to present
  • Lower Granite (GRA) 2016 to present.

Determination of Ascents and Attempted Ascents

  • A sequence of detections of a tag on a ladder are determined to be an ascent if (both):
    1. the tag is first detected on the entry coils AND
    2. the "final detection" on the ladder is at an exit coil.
  • A detection is considered the "final detection" if (any):
    • it is the last detection for that tag,
    • the next detection following a detection at an exit coil is at an entry coil (see exceptions for Bonneville below), OR
    • the next detection is at a different ladder (see exceptions for Bonneville below).
  • If the final detection is not at an exit coil, it is considered an attempted ascent.
Project Ladder Entry Coils Exit Coils
McNary MC1 0E, 0D, 0F, 10, 11, 12 01, 02
MC2 0E, 0F, 10, 11, 12, 13 01, 02, 03
Lower Granite GRA B1, B2, B3, B4 A1, A2
Bonneville BO1 04, 0F, 10, 11, 12, 13, 14, 1F, 20, 21, 22, 23, 24a 01, 02
BO2 0F, 10 01, 02, 03, 04 b
BO3 17, 18 01, 02, 03, 04 b
BO4 01, 02, 03, 04 01, 02, 03, 04
 (a) Expanded list of entry coils at BO1 due to sockeye, mainly, upstream passage behavior and detection.
 (b) Ladders BO2 and BO3 at Bonneville exit into BO4, so the exit coils are in BO4.

Special Processing for Bonneville

  • Ladder BO1 is stand-alone and is treated like the ladders at other projects.
  • Ladders BO2 and BO3 feed into BO4, thus for an ascent at BO2 and BO3, a fish must be ultimately detected in BO4.
  • Fish can backtrack from BO4 back down into BO2 and BO3, and then go back up into BO4. Thus if a fish in BO4 backs down into the "top coils" of BO2 or BO3, this is considered part of the same ascent — not a new ascent.
    • Top coils for BO2: 01, 02, 03, 04
    • Top coils for BO3: 01, 02, 03, 04
  • Some fish are only detected in BO4, presumably adults that are tagged and released into BO4. For these fish, all detections at BO4 are considered part of a valid ascent.

Fallback Calculations

In monitoring adult salmon fallback rates in real time, ideally one would like to know when fallback events occurred. Unfortunately, with only PIT-tag detection data available, we know when fish ascended the ladder but not when a fallback event occurred. For example, we might see a fish ascend through the ladder on day 1, only to see it reascend on day 4. We do not know when during that four-day period the fallback actually occurred. The practical problem is on what day the fallback event should be assigned when monitoring for changes in fallback rates over time.

A not totally satisfactory solution is to base fallback metrics on the date of known ladder ascent. This is not a perfect solution but, again, few other solutions exist and so far, none better. The consequence of this choice of data summary is that any relationship between daily fallback rates and environmental or operational covariates will be somewhat muddled.


  • Ascent: A fish seen at the entrance coils of the ladder, and subsequently and finally seen at the exit coils of the ladder.
  • Attempted ascent: A fish seen at the entrance coils of the ladder but not seen finally at the exit coils; thus, a fish seen at the entrance, then seen at the exit, and finally seen further downstream in the ladder is counted as an attempted ascent.
  • Ignored: In general, this is a fish with limited or inconclusive detection history. A fish seen only at the exit coils of the ladder or with only 1 detection.
  • N = number of unique fish to ascend the ladder or project.
    • For one ladder on one day, N is the number of unique fish to ascend the ladder on that day. The ascent day is defined by the day the fish exited the ladder.
    • Project-wide on a day, N is the number of unique fish to ascend the project on any ladder for that day.
    • Season-wide for a ladder, N is the number of unique fish to ascend the ladder over the entire season.
    • Season-wide for a project, N is the number of unique fish to ascend the project on any ladder over the entire season.
  • F = number of N that fall back, i.e., are seen attempting or ascending the same project on the same day or on a later day.
  • MSeason = total number of ascents made by the N fish.
  • MDaily = total number of ascents and subsequent ascents made by the NDaily fish.
  • P = fallback rate = F/N.
  • R = Average number of ascents per fish = M/N.


  1. One given fish can be counted more than once. For example if a fish ascends a ladder on days 1, 3, and 4,
    1. For day 1, it will contribute 1 count to N, 1 to F and 3 to M.
    2. For day 3, it will contribute 1 count to N, 1 to F and 2 to M.
    3. For day 4, it will contribute 1 count to N, 0 to F, and 1 to M.
  2. One given fish can be counted differently across ladders of a project. If a fish ascends ladder 1 on day 1, ladder 2 on day 4 and ladder 1 on day 6,
    1. For ladder 1, day 1, it will contribute 1 count to N, 1 to F, and 3 to M.
    2. For ladder 2, day 4, it will contribute 1 count to N, 1 to F, and 2 to M.
    3. For ladder 1, day 6, it will contribute 1 count to N, 0 to F, and 1 to M.
  3. Due to points 1 and 2 above, the project statistics for a given day cannot be inferred from the sum of statistics for the individual ladders on that day.
  4. Similarly, the season-wide statistics cannot be inferred from the sum of the daily statistics.
  5. During the season, statistics for previous days are updated retroactively. For example, if a fish that initially ascended on day 1 is seen ascending again on day 4, the day 4 calculations will update the statistics for day 1.
  6. Season-wide, project-wide estimates are the only parameters estimated absolutely. All other measures should be regarded as only indices of fallback behavior.

Notes on the DART PIT TAG Dataset

On a daily basis, we upload a daily file from PTAGIS, the primary source, into the Columbia River DART PIT TAG dataset. The Columbia River DART PIT TAG dataset does not include orphan tags (tags that have been detected but are not yet associated with a particular release). On a weekly basis, we synchronize the Columbia River DART PIT TAG dataset with year-to-date data from PTAGIS.

Additional Information:

Please refer to the PIT Tag and ESU Metadata & Glossary for more information.