Ask a Fisheries Biologist: Mapping fish species movement

Wisconsin is home to more than 160 fish species. Of those, anglers routinely target only one or two dozen of them, leaving a whole lot of rare species that anglers do not often see. 
DNR biologists document where these rare species occur throughout Wisconsin and have “distribution maps” that show the waters where we have observed each species. Wisconsin fish surveys have gone on for more than 100 years, and as a result, we have a good idea where different species occur and the maps do not change much.