DOI: 10.5061/dryad.5x69p8djn
title: Data from: Environmental DNA reflects differences in freshwater habitat use between two Pacific salmonids at fine temporal scales

description: Environmental DNA (eDNA) has emerged as a powerful tool to detect aquatic
 species, providing a non-invasive survey option for applications in
 freshwater fisheries, including delineating habitat use and informing
 stock management strategies. For species like salmonids with life
 stage-specific habitat requirements and timing, effective use of eDNA for
 species detection at fine spatial and temporal scales is contingent upon a
 robust understanding of eDNA detectability across all life stages. We
 conducted a 12-month eDNA survey in two Canadian rivers to describe
 temporal variation in eDNA concentrations of two anadromous fishes,
 Chinook (Oncorhynchus tshawytscha; Salmonidae) and coho salmon (O.
 kisutch), and relate this to important life history periods, including
 spawning, egg incubation, fry emergence, rearing, and outmigration. We
 sampled downstream of known spawning grounds and found that
 discharge-corrected eDNA concentrations were closely associated with known
 migratory patterns across species. For example, eDNA concentrations peaked
 during fall spawning for both species and followed similar monthly trends,
 although Chinook eDNA increased earlier than coho, reflecting their
 earlier run timing in summer. Sharp declines in eDNA were observed
 following spawning and concentrations remained low until spring when small
 spikes were detected as a result of fry emergence and rearing. We also
 found evidence of eDNA concentrations providing species detection at fine
 temporal scales in rivers, as a large hatchery release of Chinook was
 detected by eDNA only on the day of release and not on subsequent days.
 These results demonstrate eDNA as a temporally specific and effective
 detection tool across salmonid freshwater life stages, and highlight the
 promise of eDNA for assessing major life history periods of Pacific salmon
 in freshwater. Overall, our work builds on the rapidly growing field of
 eDNA for applications to fish and fisheries and reinforces the promise of
 this technology for improving current management practices.
description: # Data from: Environmental DNA reflects differences in freshwater habitat
 use between two Pacific salmonids at fine temporal scales Dataset DOI:
 [10.5061/dryad.5x69p8djn](https://doi.org/10.5061/dryad.5x69p8djn) ##
 Description of the data and file structure **Article
 Title:** Environmental DNA Reflects Differences in Freshwater Habitat Use
 Between Two Pacific Salmonids at Fine Temporal Scales **Authors:** Brock
 Burgess, Richard Chea, Kristen Westfall, Cathryn Abbott, Josephine
 Iacarella **Journal:** Environmental DNA **Corresponding Author:** Brock
 Burgess **Email:**
 [brocktyburgess@gmail.com](mailto:brocktyburgess@gmail.com) |
 [brock.burgess@dfo-mpo.gc.ca](mailto:brock.burgess@dfo-mpo.gc.ca) ###
 Files and variables #### File: life_history_data_dryad.xlsx
 **Description:** These data support the analyses presented
 in **Environmental DNA Reflects Differences in Freshwater Habitat Use
 Between Two Pacific Salmonids at Fine Temporal Scales**. The dataset
 includes qPCR and environmental data collected during a 12-month
 environmental DNA survey of Chinook and coho salmon in two Canadian
 rivers.  Note: Missing or absent data is denoted with "NA" #####
 Variables **"ReadMe"** sheet with description of variables
 "**Dataset**" sheet **SampleID:** A unique sample ID for each
 filter. **Species:** Species targeted using qPCR. Either Chinook or Coho
 salmon. **Site:** Name of sampling site. Either Chehalis River or Slesse
 Creek. **Year:** Year of sample collection. **Month:** Month of sample
 collection. **Day:** Day of sample collection. **SampleDay:** Sampling day
 within each month. Either 1, 2, or 3. **TechRep:** A number assigned to
 any of the four qPCR technical replicates used for each filter. Can be 1,
 2, 3 or 4. **Temperature:** Water temperature measured in degrees Celsius
 just below the water surface at each eDNA sampling site. **Turbidity:**
 Turbidity measured in FNU using water collected just below the water
 surface at each eDNA sampling site **Discharge:** Discharge measured in
 m^3^/second across the channel. **Volume:** Volume in liters of water
 filtered across three glass fiber filters. **Cq:** Cq values generated via
 qPCR using either the Chinook or Coho assay. **edna:** eDNA concentrations
 measured in copies/uL. **edna.vol:** "edna" divided by
 "Volume". **edna.discharge:** "edna.vol" multiplied by
 "Discharge". 
 
 "**eLowQuant Predicted SQs**" sheet **NumDetects**: The number
 of positive eDNA detections out of the 4 qPCR replicates ran for each
 sample. **SQ**: Predicted starting quantity (copies/uL) of eDNA given
 "NumDetects". **SE_SQ**: Standard error of "SQ".