Pacific salmon in the Canadian Arctic highlight a range-expansion pathway for sub-Arctic fishes

The R code and data to support the manuscript "Pacific salmon in the Canadian Arctic highlight a range-expansion pathway for sub-Arctic fishes" published by Dunmall & Langan et al. 2024 in Global Change Biology. Briefly, this study investigated the mechanisms behind variable, rising catches of Pacific salmon by subsistence fishers in the Canadian Arctic. Detailed descritptions of the data and the performed analyses are provided in the associated manuscript.

Methods
Salmon catch data (2000-2022) were collected during regular fishing activities by subsistence fishers participating in the Arctic Salmon program (https://www.arcticsalmon.ca/home) and summarized to annual counts. These salmon counts were then compared to sea surface temperature (SST) and sea ice data derived from the NOAA OI SST V2 High Resolution Dataset (https://psl.noaa.gov/data/gridded/data.noaa.oisst.v2.highres.html). Specifically, environmental data, cropped to ocean areas using a provided shapefile, were analyzed in a polygon in the Chukchi Sea (vertices: [68.3°N, 170.0°W], [68.3°N, 166.4°W], [69.5°N, 166.4°W], [69.5°N, 170.0°W]) and a polygon in the Beaufort Sea (vertices: [70.5°N, 153.0°W], [69.8°N, 143.0°W], [71.3°N, 143.0°W], [72.0°N, 153.0°W]). For the Chukchi Sea polygon, the mean June SST and last day of the spring-summer period with a mean ice concentration of at least 0.5 were calculated. For the Beaufort Sea polygon, the number of days with a mean SST above 2°C and the last day of the spring-summer period with a mean ice concentration of at least 0.5 were calculated. These environmental covariates were then compared to the annual salmon catch counts. For more detailed methods information and a description of how these data were subsequently analyzed, see the associated manuscript.

Additional files are included for the purposes of data cropping and plotting only, as described below.