Strategic management of thermal refuges in the Restigouche River

by Carol-Anne Gillis, Biologist

Between 2011 and 2013, the RRWMC, in collaboration with PhD Student Stephen Dugdale, acquired high-resolution optical and thermal images on 862km of river yielding a database of 1825 classified thermal refuges throughout the watershed.

We now want to start prioritizing these critical habitats for Atlantic salmon that can be enhanced and protected in the face of climate change and warming water temperatures.

The main goal is to increase the resilience of rivers and streams in the context of climate change. In fact, drought severity is projected to increase in the coming years and, consequently, summer water temperatures are rising in many river systems in North America, and this warming trend is projected to intensify in the coming decades. Thus, a comprehensive mapping of thermal refuges present in the Restigouche will enable us to protect these critical habitats because reliance on cold-water thermal refuges is expected to increase in a warming climate.

After hours spent choosing the most suitable sites based on their type, size and accessibility, we are currently in the field conducting surveys of the water temperature gradients between small streams and mainstem rivers.

With these assessments, we hope to select five thermal refuges for which we will prepare designs of in-river restoration work to extend and enhance the benefit of the refuges for freshwater species.