Mean daily river temperature of the Coppermine River, Nunavut, during the ice-free season 2018-2023

Shifts in migration timing in response to climate change have implications for fitness and survival of cold-adapted species. We used acoustic telemetry to investigate and compare environmental influences on freshwater return between sympatric anadromous Arctic Char (Salvelinus alpinus) and Dolly Varden (Salvelinus malma malma), and between overwintering locations (above or below an obstacle – a substantial cascade). Both Arctic Char and Dolly Varden that overwintered below the cascade returned to freshwater when sea surface temperature was warm and river temperature was cool, whereas Dolly Varden that overwintered above the cascade returned to freshwater at cooler sea surface temperatures and during warm and likely stressful river temperatures. Ascension of the cascade by Dolly Varden (no Arctic Char were observed to ascend the cascade) was likely assisted by high tide but unaffected by other environmental factors, including temperature. Fish demonstrated plasticity in response to inter..., , , # Mean daily river temperature of the Coppermine River, Nunavut, during the ice-free season 2018-2023

[https://doi.org/10.5061/dryad.280gb5n0z](https://doi.org/10.5061/dryad.280gb5n0z)

## Description of the data and file structure

Mean daily river temperatures recorded by a VR2AR acoustic receiver (Innovasea, Halifax, Canada) located in the lower reaches of the Coppermine River, Nunavut (67.75601 N, 115.332 W). Temperatures were corrected by comparing to a series of Hobo data loggers (Onset Computer Corp). Temperatures were aggregated (mean) by day, using local time (Mountain Daylight Time) to define days. Temperature units are Celsius.

### Files and variables

#### File: CoppermineRiverTemperature_2018-2023.csv

**Description:** Mean daily river temperature in the lower reaches of the Coppermine River, Nunavut

##### Variables

* Day: Day of year, defined using local time (Mountain Standard Time) YYYY-MM-DD
* Temperature.C: River temperature, in degrees Celsius

## Code/software

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