© 2019 Aaron Fisk - Trophic Ecology Laboratory. All rights reserved

Nettilling Lake Arctic Char Morphs

Background

Arctic char (Salvelinus alpinus) are unique in being one of the most morphologically variable fish. They also play an important role with subsistence and commercial fishing for the Inuit of Nunavut. However, there is preference for the sea-run Arctic char as opposed to any resident or land-locked Arctic char that do not migrate to the ocean. Nettilling Lake, the largest lake in Nunavut and the largest found on an island in the world, has the largest commercial Arctic char quota in the Eastern Arctic. Yet the fishery has remained dormant since 2001 due to the lack of economic viability in transporting the fish to the nearest town of Iqaluit. An undocumented Arctic char migration was seen with three different colour morphs (green, orange, and silver) in the Amadjuak River, a river that connects a smaller lake, Amadjuak Lake, to Nettilling Lake. Of those morphs, there may be indication that some are sea-run, and may be of fisheries interest. If sea-run Arctic char are migrating over 200 kms to the Amadjuak River and potentially into Amadjuak Lake, it may be potentially feasible for an economically viable fishery. With attempts to develop this fishery to bring much needed economic development to the Canadian Arctic, there is also a need to better understand the species in Nettilling Lake from an ecological perspective to ensure the fishery is sustainably managed.

To further our understanding of the different Arctic char colour morphs, we have collaborated with Government of Nunavut, Fisheries and Oceans Canada, and the Ocean Tracking Network. We are investigating the migration patterns of the different colour morphs using acoustic telemetry to ask questions such as the duration of their sea-run, annual repeatability, and differences between morphs. Along the Amadjuak River and in Nettilling Lake (by the Koukjuak River) we are also assessing the basic biology of the Arctic char colour morphs (morphometrics, age structure), as well as piecing together the trophic structure and dietary differences using stable isotopes, stomach contents, and parasite composition to uncover differences in the colour morphs. Together, this information will help develop this fishery but also ensure it occurs in a sustainable manner, all the while uncovering another unique Arctic char ecosystem.