Walleye

Description

The walleye is a freshwater fish in the perch family that is a popular and commonly-stocked game fish. Walleye are long and thin, primarily gold and olive in color, with a white belly. The back is crossed with five or more black bands. They have two dorsal fins—one spiny and one soft-rayed. The walleye’s mouth is large with sharp teeth, and it has low-light vision that helps it find prey at night. Walleye are about 2.5 to 3 feet (0.75 to 0.9 meters) in length and weigh up to 10 to 20 pounds (4.5 to 9 kilograms).

Range

Walleye are native to Canada, the Great Lakes, the Missouri River basin and the upper Mississippi River basin, and have been introduced in the western and northeastern United States. They prefer the cool, deep, quiet waters of rivers, lakes, and reservoirs. Walleye are mostly nocturnal and during the day are often found under the cover of tree roots, logs, and aquatic plants. At night, they travel to shallower waters.

Diet

This fish’s diet depends on what’s available, which usually includes small fish (such as yellow perch), large invertebrates, and insects. Feeding occurs primarily at dusk and dawn.

Life History

Walleye spawn in the spring or early summer. They spawn over gravel or rocks in rivers or shallows, where there is enough of a current to clear away sediment and aerate the eggs. Females can deposit more than 100,000 eggs, which hatch in about two weeks. A walleye lives about 10 years on average.

Conservation

The walleye population is relatively stable. Threats to these fish include climate change, channelization, erosion, overfishing, and degraded water quality. One subspecies, the blue pike, is believed to be extinct.

Few fish have such a strong fan base as the cool-water-loving walleye. The unofficial state fish of Ohio, walleye are targeted by anglers who chase these toothy predators year-round in rivers and lakes, from boats and shore, and even through the ice. But in Ohio, the walleye is at risk of dramatic population decline as warming lakes are decimating their prey and increasing the threat of invasive species.

Lake Erie is the most biologically productive of all the Great Lakes, often producing more fish for human consumption than all the other Great Lakes combined. However, climate change now threatens this lake and the walleye it supports as Lake Erie water levels, already below average, could drop four to five feet by the end of this century, significantly altering shoreline habitat and decreasing water quality. Rising temperatures could also change internal water cycling in the Great Lakes that would lead to oxygen-deficient zones (dead zones) that result in large fish kills. One species that's particularly sensitive to these dead zones is the cisco, a major prey item for walleye. As warming waters decimate cisco populations, the Lake Erie walleye population is likely to follow. The changing climate could also result in more suitable temperatures for non-native aquatic species to invade and expand their range into the Great Lakes and compete with walleye for food sources.

Changes in the Earth’s climate directly threaten treasured wildlife-associated pastimes in Ohio. And fishing, hunting, and wildlife-watching aren't just recreational pastimes; they are also a major contributor to Ohio's economy. Millions of sportsmen and women and wildlife enthusiasts participate in wildlife-associated activities in Ohio each year. However, this rich community of fish and game, and the economy that depends on it, is at risk from a warming world.

Fun Fact

The walleye is named for its opaque, cloudy-looking eye, which is caused by a reflective layer of pigment called the tapetum lucidum. This layer helps it (and other nocturnal animals) see in low light.

Sources

BioKIDS, Kids’ Inquiry of Diverse Species, University of Michigan

Maryland Department of Natural Resources

Michigan Department of Natural Resources

Minnesota Department of Natural Resources

NatureServe Explorer

United States Geological Survey

U.S. Fish & Wildlife Service