June 19, 2022
By David A. Rose
If we take a walleye from a lake where the primary forage is scuds and small fish—maybe from Devils Lake, North Dakota—and transport it to a reservoir where alewives are top forage, as in Kentucky's Lake Cumberland, how long before the fish changes its feeding pattern? Not long, I suppose.
Walleyes sometimes travel long distances to follow what they like to eat. Take the fish of Lake Erie, for example. Both walleyes and smelt spawn on reefs in Ohio's Western Basin and as far west as the rivers of Michigan. Procreation finished, the smelt head east to the offshore waters of New York and at least some of the walleyes follow. It's a mass movement of both fish and food over hundreds of miles, crossing three state lines.
But the migration of a food source doesn't always mean walleyes follow. Take the disappearing act of Lake Huron's alewives since 2003. Walleyes don't migrate to Lake Michigan where alewives are still plentiful—they rely on other food sources, primarily the goby and gizzard shad. Perch have also made a comeback in the Great Lakes since the alewives left (alewives feed on young-of-the-year perch and walleye) and help to fill the void.
"If you have naturally reproduced walleye, such as in Huron, and they have some fat on them, then you know they've been feeding well throughout their life cycle," says Jim Baker, fisheries unit manager for the Michigan DNR. That's the case with Huron walleyes.
To catch walleyes, saugers, and saugeyes, it helps to know the habits of their forage. Find the bait, match your lure to the bait, get it at the same depth as the bait, and you're probably going to catch fish. One way to categorize meat-and-potatoes forage options is by shape. Here we take a look at some common walleye forage.
Short and stocky—Alewives are common throughout most of the Great Lakes, rivers, and reservoirs of the southern and eastern United States. Although they can reach 15 inches, 1- to 6-inchers are the norm. Alewives are schooling fish, found high in the water column of deep lakes and estuaries. They're easy to find on sonar as thousands pack into massive pods. In spring, they head shoreward to spawn on rocky breaklines, especially in rivers.
Walleyes grow large quickly on a diet of these high-protein fish. Proof can be seen in the fish of Lake Huron. It was common to catch walleyes over 10 pounds when alewives were abundant. Today's generation of walleyes, though healthy, average 5 to 6 pounds.
Gizzard shad have one of the widest ranges of any forage species, living in lakes, large rivers, reservoirs, estuaries, and in saltwater, from the Atlantic west to the Great Lakes and Plains states, and south into Mexico. A closely related species is the threadfin shad. Both are omnivores and, like alewives, school in massive balls high in the water column and migrate shoreward to spawn. Walleyes love to eat 1- to 2-inch young-of-the-year gizzard and threadfin shad in late summer.
In warm, shallow lakes throughout the Midwest, wide-bodied panfish such as crappies and bluegills also fill the gullets of walleyes. Young-of-the-year panfish are weed-oriented, and walleyes consistently hold near vegetation because of it.
Gobies are a new entre on the menu, brought to our waters via the ballasts of seagoing freighters. These bottom-dwellers have invaded the hard-bottomed areas of the Great Lakes in droves, although they also do well in weedgrowth. When they're available, walleyes do their best to eat them.
Long and thin—Rainbow smelt can be found from the east to west coasts, throughout the Great Lakes, the Mississippi River basin, and on in reservoirs of the Great Plains, along with the coastal shorelines of Alaska.
Like shad, smelt are schooling fish, but they can be found throughout the water column rather than just its upper reaches. Smelt are anadromous, living in saltwater or large inland lakes and spawning in tributary rivers and streams. They may migrate hundreds of miles to spawn and are an important food source wherever they swim. In the late 1990s, the smelt in South Dakota's Lake Oahe were lost during a highwater drawdown, and this severely affected the walleye population. The smelt have rebounded since then, shad have been added to the mix, and walleyes are prospering again.
Prey Type Affects Walleye Behavior
The availability of large prey items is a critical component in the production of large predators. Consequently ciscoes, also called lake herring or tullibees, play an important role in growing big walleyes. Recent research on the muscle enzymes of walleyes in several Ontario lakes suggests that walleyes may become comparatively lazy in the presence of large-bodied prey like ciscoes, which may further improve their growth potential when compared to a menu of perch alone.*
Current climate projections, however, suggest that the outlook for ciscoes, a coolwater fish, isn't good. In stratified lakes, ciscoes escape warmer surface waters by heading deep, but their ability to stay in deep, cold water is regulated by oxygen. In lakes that have oxygen depletion in deep water, ciscoes are forced into a narrow band of water that meets their temperature and oxygen demands. Meanwhile, in larger, windswept systems that don't stratify, ciscoes are forced to deal with ambient water temperatures. Today, summerkills of ciscoes have become more frequent. These kills typically occur in August.
The effects of climate change on walleye populations remain unclear. Certainly, warmer summers may cause even more summerkill situations, and any reduction in cisco numbers is bound to affect the walleye populations that depend on them.
*Kaufman, S. D., J. M. Gunn, G. E. Morgan, and P. Couture. 2006. Muscle enzymes reveal walleye (Sander vitreus) are less active when larger prey (cisco, Coregonus artedi) are present. Can. J. Fish. & Aquat. Sci. 63:970-979
Many shiner species are an important forage option throughout North America. They live in nearly every creek, river, lake, and swamp east of the Rocky Mountains, from northern Canada south to Mexico. Some of the most prolific species of importance are emerald, spottail, striped, common, red, rosyface, spotfin, redfin, weed, and mimic shiners.
Many, but certainly not all, can be found throughout the entire water column, though emerald shiners live only in the warmest waters of a lake, well above the thermocline in summer, then move shoreward as the lake cools. Spottails, meanwhile, are bottom-dwellers, hiding in and feeding among weeds, rocks, and wood.
Creek chubs inhabit sandy, gravelly, and rocky streams and lakes. Walleyes target them in rivers during spring spawning runs, and again as they move back into rivers in fall.
In the same family as the walleye is the prolific yellow perch, which can be found in deep, cold, natural lakes, rivers, and reservoirs, as well as in shallow, warm water from the East Coast throughout the Great Lakes, to the Plains states and into Canada.
Although thought of as bottom-dwellers, perch suspend above the thermocline when shiners and insects are present. Young-of-the-year perch usually seek shelter in vegetation and often are a primary walleye target.
In-betweeners—On the dinner plate of walleyes in relatively sterile inland lakes throughout the Midwest, Mountain States, northern Great Lakes, and Canadian Shield lakes are thick-bodied whitefish and ciscoes, also known as lake herring or tullibee.
The waters whitefish and ciscoes inhabit range from deep, cold, and low in nutrients to medium-fertile waters that host both cool- and warmwater species. Ciscoes in particular are considered one of the best food sources for growing big walleyes.
Trout, especially stocked rainbows, also are attractive forage and have the potential to grow world-class walleyes. Rainbows inhabit all parts of the water column during spring, fall, and winter. They're available to walleyes during most of the year. During summer they often hold just below the thermocline, where some walleyes probably follow them.
Creepy critters—Insects and crustaceans make up a portion of the walleye diet. Walleyes gobble up tiny scuds, or freshwater shrimp, as they flap their fan-like tails and scoot along lake and river bottoms, often near thick weeds and wood.
Crayfish often are a target, too, especially in lakes where other forage is in short supply during some yearly periods. Walleyes probably don't gain a lot of weight on crayfish, but they can sustain fish through lean periods.
Making up one of the largest parts of the forage scene are insects. Perhaps the most common and abundant are species of mayfly, eaten in both adult and emergent form. Emerging nymphs are an easy target as they waggle their way up from the bottom during an early-summer hatch. Walleyes often gorge on them so heavily that the fish become difficult to catch, being fully sated.
Juvenile lampreys are an overlooked prey option, with different species found in the Northwest, Northeast, Midwest, and in Great Lakes waters. The eel-like, jawless lamprey preys primarily on soft-scaled fish—especially trout and salmon. With rows of sharp teeth, they attach themselves to the outside of the fish, feeding on blood and tissues. Walleyes eat immature lampreys, though it isn't known how important a prey item they are.
Walleyes are omnivorous predators, though their primary targets are fish. Understanding which prey species fish are keying on at any time and place can lead you to logical choices about lure shape, color, and size, from spring throughout summer and into fall.
*David A. Rose is a writer, photographer and fishing guide who lives near Traverse City, Michigan.