The Great Lakes basin includes numerous rivers and freshwater streams attracting fishermen from across the globe. Popular sport fish including brook trout and small-mouth bass spend portions of their life cycle migrating to and from the Great Lakes to these freshwater streams to spawn, feed and grow.
Through the coordinated efforts of the Upper Midwest and Great Lakes Landscape Conservation Cooperative (LCC), federal, state and academic partners are working side-by-side to determine how projected warmer air temperatures and changes in precipitation in the coming century may impact fish habitat.
Researchers with U.S. Geological Survey are working alongside Wisconsin Department of Natural Resources (DNR), Michigan Institute of Fisheries Research and Michigan State University to model the potential impacts of increasing air temperatures and changes in precipitation on water temperature and flow in freshwater streams that are part of the Great Lakes system. The models project future distributions for 14 fish species based on known fish locations, their habitat preferences, their adaptability to different water temperatures, existing and future stream conditions, and projected climatic changes.
The models show that the distribution of brook trout, which requires cold water for survival, is projected to shrink by 60 percent in some Wisconsin streams by mid-century, an impact attributed to warmer waters as a result of a changing climate. Loss of suitable freshwater habitat for this and other popular sport fish species due to climate change has economic implications as well, as recreational fishing opportunities across the Great Lakes system contribute to a multi-billion dollar tourism and recreation industry.
Aquatic resource managers are using model results to help prioritize on-the-ground conservation and restoration efforts while considering the potential impacts for the broader Great Lakes landscape. For example, the Wisconsin DNR is using the results to help make informed management decisions on easement properties that boast more than 35,000 acres of trout and small mouth bass streams.
“We can identify streams where fish populations may have a higher or lower likelihood of changing as a result of projected climate change impacts. This means we can make better investments in groundwater and storm water protection measures or implementation of agricultural best management practices in higher priority areas,” said Paul Cunningham, Wisconsin DNR fisheries biologist.
By examining current and future fish distributions, existing opportunities for public access and weighing demands for recreational fishing, natural resources managers across the upper Midwest and Great Lakes will be equipped with the tools needed to make strategic conservation decisions, such as how habitat is managed and when and where additional land should be acquired.
Scientists are working with natural resources managers across the region to ensure they have access to this valuable scientific data that will help guide future management decisions in the face of a changing climate.
This project is a collaborative effort by the U.S. Geological Survey, Wisconsin DNR, Michigan Institute of Fisheries Research and Michigan State University. Funding support was provided by the Great Lakes Restoration Initiative through the Upper Midwest and Great Lakes Landscape Conservation Cooperative.