Past, Present, and Future Contributions of Hatchery-Reared Walleyes to Populations in Northern Green Bay, Lake Michigan

Hatchery-reared walleyes have played an important role in rehabilitation of Great Lakes walleye populations.  For example, stocking efforts to rehabilitate remnant walleye populations in northern Green Bay, Lake Michigan began in 1969, after populations nearly collapsed.  Some natural reproduction was documented as early as 1988, but no quantitative data existed for assessing contributions of hatchery- and naturally-produced fish.  This data gap and the changing environment of northern Green Bay have hindered efforts to define the extent of population recovery and the future role of hatchery fish.  We used oxytetracycline (OTC) marking to determine the relative contribution, growth, and survival of stocked walleyes for the 2004-9 year classes of walleyes in Little and Big bays de Noc in northern Green Bay.  Marking study results, combined with spatial information on juvenile walleye abundance and historic harvest data, provide insight into the past, present, and future walleye management potential of each bay.  This information provides the basis for ecosystem-specific management that makes cost-effective use of hatchery-reared walleyes.  Such an approach can be applied to other nearshore areas to help optimize use of hatchery resources.