Walleye are popular freshwater fish known for their predatory nature. Their diet is not static; they adapt to what is available in their habitat, making them opportunistic predators. Understanding their feeding habits is important for appreciating their ecological role and for successful recreational fishing.
Primary Food Sources
Walleye are primarily fish-eaters. Yellow perch are a common and preferred prey for adult walleye, often making up a significant portion of their diet. Other frequently consumed fish include various minnow species, such as shiners and emerald shiners, ciscoes, and smelt. Walleye also prey on juvenile fish of other species, including their own, especially when other forage is scarce.
Beyond fish, walleye also consume larger invertebrates. Crayfish are a notable food source, as walleye possess strong jaws and teeth capable of breaking their exoskeletons. Leeches and various aquatic insects, particularly their larvae, also contribute to their diet, especially for younger walleye or when fish prey is less abundant. Walleye are ambush predators, utilizing their keen eyesight in low-light conditions to hunt effectively.
Factors Influencing Diet
Several environmental and behavioral factors influence walleye diet. Water temperature plays a role, as walleye are cold-blooded and their metabolism is directly affected. While their preferred temperature range for activity is 60-70 degrees Fahrenheit (16-21 degrees Celsius), they adapt their feeding behavior to colder water. In colder water below 50 degrees Fahrenheit (10 degrees Celsius), they feed less often and more selectively, preferring smaller prey.
Light conditions are a significant factor. Walleye possess specialized vision adapted for low light, thanks to a reflective layer in their eyes called the tapetum lucidum. This gives them an advantage over many prey species during dawn, dusk, cloudy days, or in deeper, murkier waters. Consequently, they are often most active and feed aggressively during these low-light periods.
Prey availability is a primary determinant; walleye are opportunistic and consume whatever is most abundant and accessible. This leads to regional differences in diet, such as walleye in Lake Erie consuming threadfin shad, while those in Lake Winnipeg heavily rely on rainbow smelt. Habitat type also influences diet; river walleye may consume prey available in current breaks, compared to lake walleye. Seasonal changes also impact feeding patterns, with increased activity during summer peaks and adapted prey selection throughout the year, including during winter when metabolism slows.
Life Stage Diet Variations
The diet of a walleye changes as it grows from a tiny fry to a mature adult. In their initial larval stage, walleye fry primarily feed on zooplankton, which are microscopic aquatic animals like copepods and cladocerans. These tiny organisms are the first food source for the newly hatched walleye.
As walleye transition into the juvenile stage, typically when they reach about 1.5 inches in length, their diet shifts. They begin to consume larger invertebrates, such as insect larvae and small crustaceans, before progressively incorporating very small fish into their meals.
Upon reaching adulthood, walleye become predominantly piscivorous, focusing on larger forage fish. This shift to larger, more energy-rich prey is driven by their increasing size and metabolic demands for growth. Adult walleye remain opportunistic, occasionally supplementing their diet with larger invertebrates like crayfish.