Identifying and classifying cold-water patches throughout the Restigouche River watershed to protect and enhance thermal refuges for Atlantic salmon

Project description

Extended low flow events resulting in warmer water temperatures are an emerging problem in eastern Canadian rivers. In the context of climate change, thermal refuges are increasingly becoming key habitats for resilient Atlantic salmon populations. Evidence-based decision-making is at the forefront of our collaborative partnerships with indigenous communities to protect Atlantic salmon habitat. Therefore, between 2011 and 2013, we acquired high resolution optical and thermal imagery on 862 km of river, creating a database of 1825 classified thermal refuges throughout the Restigouche River watershed. This comprehensive mapping enabled us to create a decision matrix tool based on refuge type to help managers strategically prioritize efforts towards identifying, mapping, preserving and enhancing these critical habitats for Atlantic salmon. Our recent management efforts, to mitigate climate change-driven habitat loss, target thermal refuge types that can be protected under conservation agreements with land-owners. Detailed mapping of the drainage areas of these thermal refuges using LiDAR will allow us to identify catchment areas and identify land-use practices that threaten cold-water persistence that Atlantic salmon rely upon. This project is a perfect example of how fundamental research on river thermal regimes can inform local management efforts. The Restigouche River watershed is the first catchment to be so extensively mapped in terms of high resolution optical and thermal imagery and the first project of its kind across the geographical range of Atlantic salmon. Creating and preserving optimal habitat for sustainable Atlantic salmon stocks in the Restigouche River is intrinsically linked to cold water temperature regimes.

Project results

NBETF decision tree ASCF Matapedia 10 refuges

Next steps

FFQ PRMHH protection (in progress). Protect thermal refuges and associated wetlands at the county level CNFASAR 2022: enhance confluence plumes and initiate innovative land use approaches, with private owners and industry, towards the protection of thermal refuges.

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