DOI: 10.5061/dryad.mgqnk99c2
title: Quantifying component mortality estimates of out-migrating juvenile steelhead (<em>Oncorhynchus mykiss</em>)

description: 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).
description: # Quantifying component mortality estimates of out-migrating juvenile
 steelhead (*Oncorhynchus mykiss*) Dataset DOI:
 [10.5061/dryad.mgqnk99c2](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](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.