EPA Research Partner Support Story: Identifying cold water refuge areas for trout and salmon
Partner: Houlton Band of Maliseet Tribe (Maine/New Brunswick)
Challenge: Identifying cold water refuge areas for brook trout and Atlantic salmon in the Meduxnekeag subwatershed on the Maine/New Brunswick border, as well as potential restoration actions to improve coldwater habitat
Resource: A fine-resolution spatial statistical (SSN) stream temperature model and an evaluation of the coldwater refuge distribution
Project Period: 2019 – 2020
An international memorandum of understanding is in place between the Maliseet Tribe and the U.S. and Canadian federal governments with a goal of supporting habitat restoration in the transboundary Wolastoq (Saint John River) watershed for coldwater fisheries. A primary concern are Atlantic salmon populations, which are severely threatened overall and extirpated in portions of the watershed. Protection and restoration of habitat for coldwater fisheries requires knowledge of the distribution of thermal regimes within the watershed during the hottest portion of the summer with low baseflows.
“EPA ORD’s temperature modeling for the Meduxnekeag watershed has been eye opening, both for our understanding of the potential impacts of climate change on our goal of restoring and sustaining cold water fisheries and migratory fish and for identifying opportunities to mitigate those impacts in a strategic and targeted way. This understanding has helped us prioritize next steps, like our ongoing effort to find ways to work with farmers in the watershed on increasing riparian buffers in active farmland.” – Houlton Band of Maliseet Indians, Environmental Planner Sharri Venno
In response to a request for technical assistance from the Maliseet, EPA researchers worked with the tribe to develop a fine resolution stream temperature model for the Meduxnekeag subwatershed that could be used to evaluate how the distribution of coldwater habitat varied between wet and dry years and simulate the effects of restoring riparian buffers. The model indicated that the mainstem of the Meduxnekeag provides only warm water habitat during July to August and that headwater tributaries are critical for providing cool- and cold-water habitat during times of thermal stress. The fraction of cool- and coldwater stream reaches could be expanded by restoring forested riparian buffers, with greatest benefit achieved with 30-meter width buffers as compared to wider buffers. During extremely dry years, little coldwater habitat remains and additional instream restoration practices may be required for mitigation. The Maliseet Tribe is using these results to guide their restoration activities in the Meduxnekeag and to support grant applications for those activities. Results have been published and shared with the Meduxnekeag working group coordinated by EPA Region 1 (New England) and composed of Tribal, U.S. and Canadian federal and provincial agencies.