Data and code from: Brook trout thermal habitat selection in stratified lakes: diel patterns, body size, and the importance of thermal time
Data files
Jan 30, 2026 version files 4.06 MB
-
BT_THS_hour_subset.csv
4.02 MB
-
Clean_RScript.R
40.82 KB
-
lakevolumes.csv
1.12 KB
-
README.md
2.52 KB
Abstract
Thermal habitat selection is a key consideration when assessing the capacity of ectotherms to tolerate warming conditions during summer. We used high dimension acoustic arrays in three lakes to determine diel thermal habitat selection by free-ranging adult brook trout with surgically implanted acoustic tags (fork length range, 26.2–54.5 cm).
Brook trout occupied a range of temperatures during lake stratification when warm surface waters and cold hypolimnetic waters were present. The overall mean occupied temperature was close to literature estimates of a single preferred temperature (15°C), but few individuals spent most of their time at this temperature. The preferred temperature range was 13–17°C in each lake while < 10°C and > 20°C were avoided. Individual variation was extensive and closely associated with body size. Despite wide diel variation in patterns of thermal habitat selection, thermal time (degree-hours; °C-hrs) was consistent and inversely related to body size over a month. Large adult brook trout accumulated fewer degree-hours than smaller brook trout. The intercept of this relationship was close to their sublethal threshold as defined by physiological stress.
We hypothesize that adult brook trout actively manage metabolic rate as a function of body size over periods greater than the diel cycle.
Dataset DOI: 10.5061/dryad.bk3j9kdq0
Description of the data and file structure
The data and files in this Dryad are those required to reproduce the analysis and figures in the associated manuscript. They consist of hourly mean temperature occupied by individual fish in the three study lakes, lake volumes categorized within thermal strata, and the R file uses to run the analysis and produce figures.
Files and variables
File: lakevolumes.csv
Description: proportional volumes of thermal habitat present in each study lake (as above)
Variables
- lake: study lake (3 levels; Scott Lake, Stringer Lake, Welcome Lake)
- zone: thermal habitat zone (5 levels; cold = < 10°C, cool = 10-13°C, opt = 13-17°C, warm = 17-20°C, hot = >20°C)
- zone_tot: mean availability of thermal habitat zone (proportion of total lake volume)
- zone_max: zone maximum proportion of lake volume calculated over study month
- zone_min: zone minimum proportion of lake volume calculated over study month
File: Clean_RScript.R
Description: R Script to reproduce analyses and plots within manuscript
File: BT_THS_hour_subset.csv
Description: brook trout hourly temperatures interpolated from depths (VPS data) in Scott Lake, Stringer Lake, and Welcome Lake in Algonquin Provincial Park.
Variables
- lake: study lake (3 levels; Scott Lake, Stringer Lake, Welcome Lake)
- fish: individual fish ID (55 levels; coded XX000 where XX is lake code, 000 is fish number specific to lake)
- year: study year (2 levels; 2009 for Scott and Stringer, 2014 for Welcome)
- date: date of detection (yyyy-mm-dd)
- FLEN: fork length (millimetres)
- datetime: date and time of detection (yyyy-mm-dd hh:mm, Eastern Daylight Time)
- month: detection month as numeric value (7 = July)
- day: detection day (relative to month; 1-31)
- temp: interpolated temperature in °C
- mean: overall mean occupied temperature (mean of all temps for individual fish)
- hour: hour of detection (0-23)
- time: detection time (hh:mm:ss)
- period: detection time of day (4 levels; DT = daytime, EC = evening crepuscular, NT = nighttime, MC = morning crepuscular. See manuscript for definition of periods)
Code/software
R is required to read and run the script and notepad or equivalent is required to view the csv files.