Brook trout occupancy in the Mixedwood Plains Ecozone, Ontario

The Ontario Ministry of Northern Development, Mines, Natural Resources and Forestry compiled brook trout presence and absence data for rivers and streams within the Mixedwood Plains Ecozone of Ontario. Data from hundreds of electrofished sites were grouped into two time periods, past (1970-1980) and recent (2000-2010), to quantify the change in brook trout occupancy in streams of the Mixedwood Plains Ecozone in Ontario at different spatial scales. The data include information for five spatial scales: 1) tertiary watersheds; 2) quaternary watersheds; 3) the well-sampled Credit River-Sixteen Mile Creek tertiary watershed; and, 4) sites within 50 m of each other were sampled in both the past (1970-1980) and recent (2000-2010) periods, and 5) at each spatial scale brook trout occupancy along the longitudinal axes of the rivers was assessed using Strahler stream order. This data set will be cited in a manuscript that quantifies the declines in brook trout occupancy in rivers and streams of southern Ontario.

Methods
Brook trout presence or absence data were extracted from a compilation of electrofishing sampling data collected by the Ontario Ministry of Northern Development, Mines, Natural Resources and Forestry, 22 Conservation Authorities, Fisheries and Oceans Canada, and the Royal Ontario Museum. Additional site data include tertiary or quaternary watershed codes, the number of sites where brook trout were present, the number of sites where brook trout were absent, the Strahler stream order of the sites, and the mean number of times the sites were sampled during the past (1970-1980) and recent (2000-2010) time periods.