DNR App Shows Michigan Fish Population Trends


The Department of Natural Resources has a new application designed to educate anglers and fisheries professionals on local and regional trends in abundance, growth, and survival of important fish populations in selected streams across Michigan. The application was developed by the fisheries division and incorporates data collected from a network of fish population survey sites, with data for some sites going back to 1947.

“The new Stream Fish Population Trend Viewer features more than 40 streams that represent a range of conditions in terms of stream size, temperature and Great Lakes access,” said Troy Zorn, DNR fisheries research biologist. “The focus is on streams with long-term data and naturally reproducing populations of trout, Great Lakes salmonids or smallmouth bass to provide users with information on self-sustaining fish populations around the state.”

Since trends in stream fish populations are largely influenced by regional climate and flow conditions, repeatedly going back to the same locations annually provides a clear understanding of trends in a stream. Users will be able to see what the population trends are in different areas of the state by comparing trends for key sites in each region.

For fishery managers, understanding regional trends is critical to determine the best course of management on these streams, as well as interpreting survey data on streams that are surveyed less frequently. Anglers, fisheries professionals and the public will be able to look up a river and see what the most recent trends are in terms of abundance, growth and annual survival of selected fish species. Information can be viewed in map, graph or table formats. Approximately half of the sites are sampled each year, and the new data will be added annually to the trend viewer app prior to spring.

The app was developed in collaboration with the Michigan Department of Technology, Management and Budget, and Michigan State University and funded by the Great Lakes Fishery Trust.

The app can be found at mcgi.state.mi.us/fishpop/