Quantifying component mortality estimates of out-migrating juvenile steelhead (Oncorhynchus mykiss)
Data files
Sep 18, 2025 version files 56.99 MB
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Events_tidy_Dryad.csv
60.07 KB
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PDAT_dets_tidy_Dryad.csv
56.93 MB
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README.md
4.46 KB
Abstract
Our study aimed to partition juvenile steelhead mortality among component sources using Predation Detection Acoustic Tags (PDATs). From March–May 2024, we tagged 300 juvenile steelhead (Oncorhynchus mykiss) (236 ± 30 mm fork length, range 144 – 302 mm) with PDATs and detected tagged fish using a passive receiver array in the San Joaquin River, CA, coupled with eight days of active tracking following each release. We categorized passive and active PDAT detections into three observations: (1) alive, (2) fish predation, and (3) unobserved. Additionally, we determined whether mortality was significantly related to biotic (e.g., fish size at release) and abiotic conditions (e.g., temperature, discharge).
Dataset DOI: 10.5061/dryad.mgqnk99c2
Description of the data and file structure
This dataset was collected as part of a research project aimed at quantifying sources of mortality in out-migrating juvenile steelhead (Oncorhynchus mykiss) in the California Central Valley, San Joaquin River system during spring 2024 from March–May. Experimental efforts combined passive receiver arrays and daily boat-based manual tracking to detect acoustic tags released in juvenile steelhead. The study used Predation Detection Acoustic Tags (PDATs), which can identify predation events and differentiate between predation by fish (ectothermic) and by birds or mammals (endothermic) based on tag-logged temperature. Active tracking was conducted using a hydrophone setup on a research vessel for eight consecutive days post-release to relocate tagged fish, while a passive array of acoustic receivers covered the study reach for longer-term detection. Additionally, manual observations of predator species and habitat features were recorded during vessel transects to analyze environmental and biotic correlates of mortality. The resulting dataset supports empirical estimates of component mortality and informs management strategies for threatened steelhead populations.
Files and variables
PDAT_dets_tidy_Dryad.csv
Description:
This file contains telemetry detection records for tagged juvenile steelhead monitored using PDATs. Each row represents an individual detection event from both the passive acoustic array and active tracking effort. The dataset includes the telemetry detection records (DateTimeUTC, Receiver, Transmitter, RawSensorValue, SensorUnit, Latitude, Longitude, Mode) with additional metadata columns included for the passive array (Gate_edit, Depth_ft) and the steelhead tagging information (Length_mm, Length_Type, Weight_g, DateTagged, RelDateTimeUTC).
Fields:
- DateTimeUTC: Detection timestamp in UTC.
- Receiver: Receiver at which detection occurred ("NA" = not applicable, occurs when Mode = "Manual" or "Auto")
- Transmitter: Unique transmitter/tag code.
- RawSensorValue: Value recorded by sensor (time or temperature).
- SensorUnit: Type of sensor value ("Time" or "Temperature"; uncalibrated).
- Latitude, Longitude: GPS location of the receiver.
- Gate_edit: Receiver "gate" (from 1-18) of detection.
- Depth_ft: Water depth at detection site (in feet; "NA" = not available, occurs when Mode = "Manual" or "Auto").
- Mode: Detection mode ("Manual" for boat tracking, "Passive" for stationary receiver).
- Length_mm: Fork length of tagged fish (mm).
- Length_Type: Fork length type (FL = fork length).
- Weight_g: Weight of tagged fish (g).
- DateTagged: Date of tagging for fish.
- Rel_DateTimeUTC: Date/time of release in UTC for fish.
Events_tidy_Dryad.csv
Description:
This file catalogs observational survey events and habitat features collected during boat tracking transects. Each record corresponds to a predator observation, habitat attribute, or other relevant event logged during a survey, along with site-specific coordinates.
Fields:
- Latitude, Longitude: GPS coordinates of event/observation.
- Speed_kmh: Vessel speed during observation (km/h).
- DatePST, TimePST: Survey date and time (Pacific Standard Time).
- Notes: Raw survey notes or description of observation.
- Event_Type_: Type of survey event (e.g., "Predator", "Habitat Attribute").
- River_Side: Bank location, if applicable ("RL" = river left, "RR" = river right, "NA" = not applicable).
- Note_Tidy: Cleaned notes field for analysis.
- Gate_edit: Receiver "gate" (from 1-18) of detection.
Code/software
The analyses and visualizations described in this data package were performed using R statistical computing software (Version 4.4.3). All code is available at: https://github.com/elizabethgreenheck/Steelhead-PDAT-2024-2025/tree/main
Access information
Other publicly accessible locations of the data:
- Water data (temperature, discharge, turbidity) used in this study were acquired from the California Data Exchange Center and were accessed via R using the "cder" library.