Re-Colonization of Lake Whitefish in the Menominee River, Green Bay

Large numbers of lake whitefish (Coregonus clupeaformis) historically spawned in the Menominee River, Green Bay.  However, by the late 1800s they were extirpated largely due to logging activities.  During the early to mid-1990s, increasing incidental catches of whitefish were recorded during November management surveys; corresponding with the whitefish spawning period.  Whitefish returns have continued to increase and it appears the population has become self-sustaining.  Beginning in 2009, we began conducting annual assessments of this population collecting information on fish size and age distribution, post-spawn movement, genetic origins, relative abundance, and mortality estimates.  Genetic analyses indicate this population is likely an admixture of fish from multiple Lake Michigan stocks.  Preliminary tag recovery data suggest, unlike an adjacent stock, fish from this population do not move out of Green Bay into Lake Michigan.  Age analysis supports the theory that this is a recently “found” population as few age classes are well represented.  This re-colonization substantiates the premise that many of the Lake Michigan whitefish stocks are in a rebuilding phase.  This phenomenon also provides a case study for potential re-establishment of extirpated whitefish runs in historically inhabited tributaries where suitable habitat exists.