"Ice out" effects on Spring Walleye Patterns

Spring Patterns- “what will late ice out do?”  "What about low or high-water levels?"

By Wade Watson “Kab Kid”  

Walleyes spawn in spring, but when is “spring” to a walleye? In our backyard of northern Minnesota "spring" or ice-out can vary by weeks or months. In 2024, ice out was maybe in March, while 2025 ice out is looking like maybe May in northern Minnesota. How do these fluctuations affect walleye age classes or the success of the walleye spawn? Let think about these questions as we try to clarify "spring walleye patterns" and eagerly wait for Minnesota fishing opener!

Water temperatures trigger walleyes to lay eggs in shallow gravel or rocky areas anywhere between 42°F and 50°F.   Biologists have found walleyes laying eggs in Minnesota and Wisconsin, as early as March 5th and as late as May 7th. When we talk about water temperatures, remember locations across the states can vary.  Most agree that spawning has specific temperature ranges, and these ideal temperatures vary by latitude. Southern walleyes prefer spawning temperatures between 48°F and 50°F, while northern states and Canadian counterparts favor temperatures between 44°F and 48°F.  According to the Minnesota DNR, Male walleye move into spawning areas in early spring when the water temperature may be only a few degrees above freezing. The larger females arrive later. Spawning reaches its peak when the water temperature ranges from 42 to 50 degrees. A five-pound female deposits more than 100,000 eggs (as many as 600,000 eggs). Neither parent cares for the eggs in any way. 

  The surface of the eggs is very sticky, so they stick to the surface of the rocks and the gravel. Their hatching takes from five days to two weeks. Male walleyes mature faster than female walleyes; the male walleyes mature in two to four years but, the female walleyes mature in three to five years.  

In the extreme Far North, if those ideal conditions don't arrive early enough, walleyes absorb their eggs and forego spawning. In the South, on the other hand, walleyes spawn successfully based on what scientists call the chill temperature hypothesis. For their eggs to develop properly, they need to spend a portion of winter in water temperatures that dip below 50°F.          

Both male and female walleye will grow 3-5 inches during their first 5 to 6 years. Once they reach maturity, their growth rate slows down to about 1 to 3 inches per year. Again, remember several external and internal factors will determine their average annual growth, and growth rates between different populations and habitats can vary greatly.  

This means that, on average, a 10-inch walleye is about 2 years old, while a 20-inch walleye can be aged 8 to 10.   It is important to remember that female walleye grow faster than their male counterparts, which means a 20-inch walleye may be 7-8 years old if it was a female, and more like 10 years old if it were a male walleye.   

Interesting new article:

A recent study from the University of Wisconsin highlights this:

Walleyes, the favorite game species in many Midwest lakes and Minnesota’s official state fish, are struggling to spawn successfully due to warming springs and highly variable ice-out dates, creating more bust years and fewer boom years for many walleye populations.

That was the finding of a University of Wisconsin study published this week in the journal Limnology and Oceanography Letters.

The problem stems from walleye being creatures of habits that developed over millennia and which can’t keep up with changing climatic conditions, especially increasingly earlier and variable ice-out dates.

The timing of walleye spawning has historically been tied to the thawing of frozen lakes each spring, said Martha Barta, a researcher at the University of Wisconsin-Madison and lead author of the study.

Within a few days of ice-out, walleyes begin laying and fertilizing eggs. That timing, in a normal year, sets tiny walleye fry up for success once they hatch. But Barta said the study found that “climate change is interrupting the historical pairing between ice-off and walleye spawning, and that threatens the persistence of walleye populations across the Upper Midwest.”

“We’ve known for several years that many walleye populations are not doing well. Now, this adds the phenology piece where we found that either a very early ice-out or very late ice-out in the spring, we didn’t see good walleye classes in the fall,’’ Zach Feiner, a co-author of the study and a fisheries biologist for both the University of Wisconsin-Madison and the Wisconsin Department of Natural Resources, told the News Tribune. “The more the ice-out varied from a normal year, the worse the walleye class was that year.” 

FYI: Typical "ice out on Namakan, and Kabetogama historically is the last week of April

Photo-period or length of day is a major factor. Why? Well, lets remember that photoperiod initiates growth in vegetation and effects water temperature changes throughout the lake structure levels (shallow sand bays vs. island structure). Food, cover, habitat, and more.

The photoperiod, or the length of daylight hours, serves as a biological trigger for many species, including walleye. As daylight hours increase in early spring, walleye begin preparing for their spawning journey. While water temperature can vary year-to-year, photoperiod remains a constant marker that helps walleye "know" when it’s time to start moving toward spawning areas.

So, "ice-out" we first think of water temperature...but I think if we look at the bigger picture, of catch-rates, seasonal yearling sizes, and DNR net sample sizes highlights the COMBINATION of a "strong" walleye year class with photoperiod as well as water temperature and consistent water levels. All three factors help produce STRONG year class for "spawning success" in the walleye world.

Spring Walleye Migrations – Spawn, and post spawn walleye patterns:

Remember, the walleye spawn will often spread out over several weeks. They won’t all spawn at the same time and some fish will spawn several weeks before the latter fish. This is especially true on larger systems where you have different water temps and different bays warming up at different times.

The biggest thing about finding fish right after the spawn is that you have to identify where they spawn. Gravel, rocky structures or shorelines are ideal, but I'm not looking for boulders. Often I start by identifying an incoming tributary, a small creek or a river channel. or a creek that’s One thing you may notice is that these small inflowing streams have warmed up sooner that larger waters of a big lake so they are dumping warmer water along the shorelines and into shallower bays. Might also be just a windswept shoreline where there’s a bunch of pea rock – those hard bottom areas. Typically, if you have good water circulation and a hard bottom, that’s where these fish are going to spawn.

How do I find these fish? Wanna use your "new" forward facing sonar? Well, those that use electronics may have an advantage in finding spring fish...and I would say "side-imaging" may help you the most. Using side imaging you can see a weed development, distances, and schools of fish. (See article on Spring Walleye fishing on your Electronics)

(From Jason Mitchell) Right after the spawn, walleye don’t necessarily go very far. Usually within about 400 yards of where these fish spawn is where you can count on finding these fish at least for the first couple weeks after the spawn. My favorite locations to look for are large flats adjacent to spawning locations that are less than 12-13 feet of water. Less than 10 feet of water is even better because these spots are going to warm up quickly. The bottom might be flat, scattered rock, might have some emerging vegetation. A lot of times, the bigger the spot, the more fish it can hold. This is not to say that smaller spots aren’t good, because they can be especially great if they’re overlooked by other anglers. With the large flats, you also want to consider the classic access to deep water, but not always. A lot of times, finding the best location for post spawn walleye is more about water temperature.

There’s a lot of different patterns that can emerge, and every lake will have its own personality, but on the vast majority of the lakes we fish, if you can find flats near spawning areas, that’s where it’s at. That flat might be a shallow bay with a tributary or creek coming into the back end of it. Maybe the fish push up into the mouth of that creek to spawn and they just hang out in that bay with the warmer water.

Water temperature is a big deal before the spawn, but it’s also a big deal after the spawn. When you’re looking for these shallow flats, keep an eye on that temperature gauge. A lot of times, if you can find the pockets of warmer water on the flat, you’ll find the fish. Another thing to look for is water color. A lot of times, if the water is cold is going to be clearer. So if you come out on these flats and can see the bottom in 10-12 feet of water, you’re probably going to struggle to catch fish.

Tip: What you’re looking for is that stained tea color which also indicates that the water has warmed up. When you look down into the water, I like to fish double the depth that I can see. So, if I can see down 3-4 feet, 8 feet is a good spot to start.

Look for that warmer, stained water and find the large flats near spawning locations and that’s a great way to find walleye early in the year right after the spawn.

This is a GREAT article I used in a blog last season that is worth the read...

Taken from In-Fisherman article by Gord Pyzer 2023 

When walleye migrations begin for spawning, we find as much variation and dissimilarity in their movement patterns as during the rest of the year, although the norm probably is different than most anglers suspect. "Mature members of all self-­propagating walleye populations, whether stream-spawning or lake-spawning, migrate from overwintering grounds to spawning grounds in spring," says Dr. Peter Colby, former head of the walleye research program of the Ontario Ministry of Natural Resources. "But the fish often aren't the long-distance runners many anglers believe them to be." 

He confirms what most walleye anglers already know: Stream spawners migrate into creeks and rivers to spawn on rock and gravel substrates. Lake spawners move inshore to spawn on shallow, windswept rock and cobble shoals. In many waters both types of walleyes coexist, a way to ensure effective spawning. 

Colby says that tagging studies indicate that most walleye populations move only a short distance. "Even in Lake Superior and Georgian Bay," he says, "a majority of spawners move no farther than three miles from their spawning grounds. Presumably, a migration of similar magnitude is undertaken to return to the spawning grounds the following spring, since evidence now suggests that mature walleyes tend to return to the same spawning grounds year after year." 

He calls this repetitive migration. He points to studies where walleyes were transferred upstream in river impoundments, only to move back downstream, past dams and other barriers, to their original locations. He acknowledges that some intermingling occurs, especially in lakes and reservoirs where spawning sites lie close to one another. 

Learned Spring Patterns 

Minnesota biologists Donald Olsen and Dennis Schupp, and Ontario biologist Val Macins, have reinforced the research Colby draws on. These scientists suggest that the ability to home into specific spring spawning sites is an adult learned behavior, an action influenced by the water's physical layout size, shape, bottom contours, and locations of suitable lake and river spawning areas. By roaming, walleyes become familiar with the best spawning areas. 

Some waters, such as the Rainy River at the south end of Lake of the Woods, the Red River at the bottom of Lake Winnipeg, the Thames River in Lake St. Clair and Lake Erie's western basin are major spawning draws. In other waters such as on Canadian Shield lakes, many smaller spawning sites exist, and spawners are more spread out. 

Olsen, Schupp, and Macins believe that the more often a walleye returns to a specific spawning shoal, the more permanent the route and site become. Walleyes must learn where to go in spring. After hatching, walleye fry is at the mercy of wind and river currents; they are dispersed throughout the lake or reservoir.  Depending on weather, the success of spawning can vary greatly year to year. Rapidly warming water can cause eggs to hatch prematurely. Prolonged cool weather can delay and impair hatching. A cold snap after the hatch can suppress the production of microcrustaceans that walleye fry eat. Year-class strength can vary 100-fold, depending on the success of the hatch and survival of the fry. One walleye year-class may dominate in a lake, while walleye a year older or a year younger are scarce. 

Walleyes develop a homing instinct to a spawning area they chose as adults. This homing mechanism, according to the three biologists, is strongest in walleyes with short migrations between summer and winter-feeding areas and spawning sites. In their words, "spawning migrations from home feeding areas likely are to the nearest spawning site, even though migrations of great distances apparently occur (in portions of some populations)." 

More interesting still, the scientists suggest that the destination of a first-time spawning walleye probably is a chance occurrence. First-time spawners travel with adults like migrating geese in fall following them to spawning sites. Regardless of how they find spawning sites, walleyes appear to choose them and then home to them with greater fidelity each year of their lives. 

This suggests that in lakes and reservoirs peppered with spawning shoals, the best fishing for larger walleyes likely is adjacent to those sites that are the best summer and winter areas for big fish.

Those spawning sites may not be the largest spawning areas in terms of physical size or numbers of fish they host; but on a micro basis, they're the best. 

Popular opening-day spots well known for producing numbers of ­eating-size walleyes, meanwhile, may or may not harbor many large fish. Indeed, these sites probably are subject to fluctuations in the number of walleyes that use them. Olsen, Schupp, and Macins suggest that "If homing is strengthened by repeated migrations, populations comprised of a large proportion of older fish, rather than heavily exploited populations of younger fish, would display stronger homing tendencies." 

Still, this can change over time, especially when enlightened management rules afford more protection to fish entering the egg-laying stage of their lives. Then, as more walleyes move into the adult ranks, Colby's reinforced homing mechanism kicks in and the age of the fish on a particular spawning location increase. 

Smarter Walleyes 

Older walleyes appear to be smarter than younger fish, which is hardly a surprise.  Larger walleyes move from spawning areas in a hurry--much faster than most anglers think. "We got into a bunch of small males," is the usual opening-day refrain from frustrated walleye anglers. "The bigger fish are recuperating and refuse to bite." But according to Colby, smaller male walleyes predominate in the spring catch because males outnumber females on the spawning grounds. Males mature at least a year earlier than females, adding at least one extra year-class of them on the shoals. 

Colby also says that larger female walleyes quickly vacate spawning areas in search of a deep-water refuge. They head for deeper regions, especially if soft-rayed forage like ciscoes and smelt are available. It isn't that they just quit feeding. 

Younger, smaller walleyes, both male and female, often forage on perch. Perch tend to stay shallow, so smaller walleyes stay shallow, too. This isn't to suggest that large walleyes don't eat perch. They certainly do, especially in emerging weed growth during the Pre-summer and Summer Peak periods. 

Small walleyes eat perch (and shiners) because these baitfish are more abundant, not just because walleyes prefer them, Colby explains. As walleyes grow bigger, however, they switch from what is most abundant to what they prefer: Soft-rayed forage like deeper-dwelling cisco, whitefish, smelt, and herring.  And walleyes also function metabolically more effectively in the depths. 

  Wade Watson, ”Kab Kid”