Identification of Dolly Varden (Salvelinus malma) in the Canadian Arctic east of the Mackenzie River

For many decades, scientists believed that the Mackenzie River in the western Canadian Arctic represented the eastern range boundary for northern form Dolly Varden (Salvelinus malma malma). However, limited mitochondrial DNA data and observations from fishers in the Arctic community of Kugluktuk, Nunavut, have suggested the occurrence of Dolly Varden east of the Mackenzie River. Using single nucleotide polymorphism (SNP) data and morphometrics, we identified Dolly Varden in three systems east of the Mackenzie River, all of which are used by subsistence fishers. Of the two systems that support established Dolly Varden populations, one, the Coppermine River, supports sympatric anadromous Arctic char and Dolly Varden, while the second, Tree River, appears to support solely Dolly Varden. Arctic char and Dolly Varden are genetically and morphologically distinct both within and between systems, and in areas where the two species are sympatric, minimal contemporary hybridization was detected. These data confirm that contemporary Dolly Varden populations are present in the Canadian Arctic east of the Mackenzie River, and that the Mackenzie River is not the eastern range boundary for the species. In addition to providing a more accurate understanding of the range of northern form Dolly Varden, these data will help inform community-based char conservation efforts by clarifying the diversity of chars in the region, allowing for targeted conservation and management initiatives.