Walleye (Sander vitreus) are popular freshwater game fish known for their predatory behavior. Understanding their diet provides insight into their ecological role and informs successful fishing strategies. These fish are widely distributed across North America, inhabiting various lakes and rivers. Their feeding habits are influenced by prey availability and change throughout their lives.
Primary Prey and General Diet
Adult walleye primarily consume other fish, acting as opportunistic predators. They feed on a variety of smaller fish species, including yellow perch, minnows, shiners, ciscoes, smelt, and suckers. Walleye may also consume smaller individuals of their own species, especially when other food sources are less abundant.
Beyond fish, walleye also incorporate invertebrates into their diet, especially when fish prey is scarce. Crayfish are a significant food source, particularly in rocky areas. Aquatic insects, such as mayfly nymphs and other larvae, also contribute to their diet. Diet composition varies depending on local prey availability.
Dietary Shifts Through Life Stages
A walleye’s diet undergoes distinct changes from larva to adult. Newly hatched larvae are very small and primarily feed on zooplankton, which are microscopic crustaceans. This early diet supports their initial growth and development.
As walleye grow into juveniles, their feeding preferences gradually shift from zooplankton. They begin to incorporate aquatic insects, such as mayfly nymphs and other larvae, into their diet. As they mature and develop canine teeth, juvenile walleye progressively introduce small fish. Adult walleye are predominantly fish-eaters, but will still consume larger invertebrates like crayfish when accessible or when fish prey is less available.
Environmental Factors Affecting Feeding
Several environmental factors influence walleye feeding. Light conditions play a substantial role due to their unique eye structure, which includes a reflective layer called the tapetum lucidum. This adaptation gives them superior vision in low-light environments, allowing them to feed more effectively during dawn, dusk, or at night.
Water temperature affects walleye metabolism and feeding activity. They prefer temperatures generally ranging between 60 to 70 degrees Fahrenheit, with peak feeding sometimes observed around 64 degrees. Seasonal changes influence water temperature and prey availability, leading to shifts in walleye feeding patterns and locations.
Physical habitat, including water depth and structures, dictates prey accessibility. Walleye frequently associate with submerged features such as weed beds, rocky shorelines, drop-offs, and underwater humps. These structures offer cover for ambushing prey and concentrate smaller fish, making them prime feeding grounds.