Evidence for Heritable Preferences for Spawning Habitat between Two Walleye Populations

The basis of behavioral differences between populations of river- and lake-spawning walleye Stizostedion vitreum was evaluated. We used fish from one population that migrates up a river to spawn on gravel bars and from another that remains in a lake to spawn on rocky shoals as broodstock to produce genetically tagged fry of each stock. Offspring from these broodstocks were introduced into a system containing both habitats. When the stocked walleyes had reached sexual maturation 3 and 4 years later, adults in reproductive condition were collected throughout the impoundment–river system. Walleyes that were the offspring of broodstock from the river-spawning population were captured more frequently in lotic habitat well upstream from the impoundment, whereas offspring of the lake-spawning population were found more frequently in lake habitat. This result is consistent with the hypothesis that choice of spawning habitat has a heritable component: walleyes have a genetically based response to environmental cues that guides them to spawning habitat.