If you’re on the water in early October, be on the lookout for Michigan Department of Natural Resources personnel conducting nighttime walleye recruitment surveys. Fisheries managers use these surveys to determine whether walleye that hatched in the spring (known as young-of-year) were born in the wild or were stocked, as well as how many are present in an area. This information about the status of young walleye in lakes helps the DNR make well-informed management decisions.

Using electrofishing boats at night, crews will survey shallow areas near the shoreline of lakes with the goal of capturing juvenile walleye. Walleye prefer cooler, deeper areas of lakes during the day but move into shallow, nearshore areas at night, making nighttime surveys more efficient. On larger lakes, two or more electrofishing crews using separate boats may operate at the same time to cover more area. The crews will work on a subsample of Michigan lakes that have been stocked with walleye, as well as lakes that have not.

Biologists also collect and keep a sample of young-of-year walleye from stocked lakes to determine whether the fish are primarily reproducing naturally or if young-of-year are from stocking. All other walleye will be released unharmed. Walleye that are stocked in these lakes are marked with oxytetracycline, a chemical marker that can be observed within captured fish by using a microscope with an ultraviolet light source in a laboratory setting.

Some surveys will be conducted collaboratively with tribal agencies; tribal natural resource departments also will conduct surveys independently of the DNR. In the Upper Peninsula, the U.S. Forest Service will also be collaborating on surveys and conducting independent surveys in the Hiawatha National Forest as part of an effort to create long-term datasets for a number of inland lakes managed for walleye.

Everyone is urged to use caution when fishing or on the water near electrofishing boats, and anyone wading will be asked to exit the water when a survey boat approaches and during electrofishing work. Crews will be using bright lights to illuminate the water around the boat and running a generator on board, which may make it difficult to hear and speak with anyone on shore, such as anglers and lake residents.

Learn more about how the DNR manages Michigan’s fisheries.