Impacts of Climate Change and Browning on Salmonid Oxythermal Habitat and Greenhouse Gas Emissions in Arctic Regions

The objective of this project is to provide essential information on the current status and future evolution of the habitat of two fish species in Nunavik and Nunavut that play a key role in the food security of northern communities: Arctic char (Salvelinus alpinus) and lake trout (Salvelinus namaycush).

Arctic char are harvested year-round, while lake trout are mainly fished in winter (ice fishing). While lake trout spend their entire life cycle in lakes, the different morphs of Arctic char are found in lakes, rivers and coastal environments, and can move from one habitat to another depending on their life stage. There is very little information on the availability and quality of the habitats of these two species, habitats that are likely to be modified by climate change. This project seeks to fill these gaps by combining field monitoring and modelling.

This project will provide a better understanding of the changes in temperature and oxygen content of lakes and rivers in response to climate change (higher air temperature, longer summer season, browning of waters), and thus qualify these habitats that provide important ecological services.

The project will also contribute to the development of management tools for anadromous Arctic char. Research efforts to date have focused primarily on 1-D modeling of lake temperature along a latitudinal gradient in Nunavik; we propose to extend this modeling effort to include the effects of water browning (increase in dissolved organic matter) on oxythermal and optical habitats from 55°N to 75°N.

In addition, this new modelling phase will provide an estimate of current and future greenhouse gas emissions from these ecosystems, since these emissions are largely dependent on temperature and oxygen content. The second objective, which consists of developing habitat preference models for anadromous Arctic char, will be achieved by making use of Inuit knowledge. Empirical river water temperature models will also be developed to provide an initial assessment of the thermal regime and its future evolution in the rivers of these territories. Through regular exchanges with local communities and government agencies, this project will provide tools to support fisheries management and food security.