Stretching across nine towns and three counties, Mille Lacs Lake has earned its French title, “thousand lakes.” At just over 200 square miles, it is surpassed only by the Red Lake as the largest inland lake in Minnesota. The lake’s northern half consists of mudflats and its southern half contains the rocky, gravelly lake bottom loved by several of its larger native fish. With a maximum depth of only 40 feet and dense vegetation, this richly-oxygenated body of water serves as a haven for many sensitive species of fish.
Its ample winds and shallow depth keep the water’s temperature evenly distributed around the lake, allowing delicate forage fish like tullibee to thrive and subsequently feed prize-winning sport fish. While hundreds of lakes throughout the country have been stocked with walleye, Mille Lacs Lake is one of only a handful that naturally hosts a prolific breeding population.
Mille Lacs Lake contains two islands which together make up the smallest wildlife refuge in the US at only 0.57 acres. This protected area, the Mille Lacs Lake National Wildlife Refuge, is home to one of only four breeding colonies of the threatened common tern. Even when completely iced over, the lake is an excellent habitat for a variety of fascinating species. This article will go over several of Mille Lacs Lake’s famous fish, as well as a few of its lesser-known inhabitants.
Fish Species in Mille Lacs Lake
1) Walleye (Sander vitreus)
If there’s one fish Mille Lacs Lake is known for, it’s the walleye. With its bright gold and olive coloration, sharp teeth, and two dorsal fins, the walleye is an easily recognized giant. As the largest member of the perch family, walleyes regularly mature at 2.5 – 3 feet but can get larger. In fact, Minnesota’s state record fish was a whopping 17 pounds and 35.75” long!
Female walleye may produce nearly 500,000 eggs per spawning season and deposit them randomly without any nest-building or parental care. These sticky eggs can safely develop and hatch in the rocky, vegetated environment of Mille Lacs Lake.
Young walleyes quickly develop a reflective strip known as a tapetum lucidum in their retina, allowing adult specimens to have excellent night vision for nocturnal hunting. The species is named for their large, cloudy eyes.
Walleyes typically hide in the shallows during the day, swimming to deeper waters to hunt at night. This fanged fish is strictly carnivorous and will eat anything small enough to fit in its mouth, including smaller members of its own species. Walleye regularly ingest small mammals and birds in addition to their largely fish-based diet.
Due to a combination of invasive species such as zebra mussels and climate change, Mille Lacs Lake has developed noticeably clearer waters. This allows walleyes to be more easily seen by prey they would otherwise have an advantage over in murky water. As a result, walleye numbers have declined in recent years.
2) Tullibee (Coregonus artedi)
Also known as cisco, tullibee are small, silver fish that are distinctly at the bottom of the food chain. While they can reach up to 4 pounds, adult tullibee rarely surpass a pound. During winters, tullibee are popular catches for ice-fishers, but they mostly serve as forage for larger species such as walleye and muskies.
Tullibee are a sensitive “canary in the coal mine” species that rapidly decline when water conditions are poor. Unfortunately, numbers have diminished in several lakes throughout Minnesota due to declining water quality and loss of habitat. On top of their sensitivity to pollution, tullibees require very specific water conditions. They can only survive in bodies of water that are cool and rich in oxygen.
In many lakes, tullibee have a dramatic die-off during the summer, when oxygen becomes isolated in warm waters. Due to its heavy winds and well-circulated waters, Mille Lacs Lake lacks the typical thermocline found in most lakes.
This distinct trait allows tullibee to thrive in Mille Lacs and consequently predator fish prosper. Despite nearly disappearing in 2007 due to an unusually hot summer, tullibee remain a prolific member of Mille Lacs’ forage base.
3) Muskellunge (Esox masquinongy)
Known as muskies by their fans, muskellunges are large, elongated fish that are often confused with northern pikes. This species can be easily distinguished from northern pikes by its forked tail, dark spot and light bar pattern along its side, and 6 – 9 pores on its lower jaw used to detect vibrations.
This massive species of solitary pike is an exclusive carnivore that begins eating other fish within a few days of hatching. At a typical adult length of 28 – 48 inches and weight of 15 – 36 lbs, adult muskies regularly ambush birds and even small mammals. This solitary species requires shallow waters with plenty of vegetation to hide in before striking.
At 55 lbs and 14 oz, the record holder for the largest Minnesota muskie was caught in Mille Lacs Lake. Similar sized fish are regularly found, including the elusive “Queen of Millie Lac”, who was released at an estimated 60 lbs.
Despite what their size may suggest, muskellunges are a short-lived species, rarely surpassing 12 years of age. Adults do not form nests or provide parental care, instead dispersing eggs at random in shallow streams and channels before leaving.
4) Smallmouth bass (Micropterus dolomieu)
Along with walleye and muskellunge, Mille Lacs Lake is practically synonymous with smallmouth bass. Per a species dedicated nonprofit, the Mille Lacs Smallmouth Alliance, Mille Lacs Lake is teeming with an estimated 67,000+ count of smallmouth bass.
With their elongated, olive-green body and white underside, the smallmouth bass is an elegant and common catch in Mille Lacs Lake. The jaw of the smallmouth never reaches further than its red eyes, but it is still large enough to allow the smallmouth bass to be a fearsome predator.
Despite their current prevalence, this native fish was almost entirely unreported in Mille Lacs Lake until the mid-1980s, when its population grew for unknown reasons. After catch regulations were put in place in 2003, smallmouths in Mille Lacs Lake boomed in terms of size and number.
This species thrives in cool, rocky bodies of water with plenty of shade and vegetation, as provided by the lake. Males prefer gravelly lake bottoms to form and aggressively guard their rounded nests.
Smallmouth bass have a highly opportunistic diet including fish and aquatic insects. They are even known to follow aquatic turtles and pounce on any crayfish or insects dug up when they burrow.
5) Bowfin (Amia calva)
As the last surviving member of its family, the bowfin is an ancient relic of the early Triassic Period. It has remained remarkably unchanged from its ancestors hundreds of millions of years ago and is almost shark-like in terms of its cartilaginous bone structure, scaleless head, and plate-like armor.
The bowfin is named for its long dorsal fin that extends approximately two-thirds of its body length, allowing it to swim forward and backward. It is olive and darkly mottled along its sides and is commonly called a dogfish due to the small, sharp set of canine teeth that can be seen while it gapes.
Bowfins are rapidly-growing carnivores that eat anything they can fit in their mouths. Hatchlings often grow more than 12 – 14 inches long in their first year alone, with adults being 15 – 28 inches long on average. Due to their vigorous hunting tendencies, bowfins are thought to keep sportfish populations at a reasonable level.
The bowfin prefers swampy areas with plenty of vegetation but is a hardy survivor wherever it swims. As a bimodal breather, bowfins regularly surface to gulp air into their lung-like air bladders as needed and can thrive even in poorly oxygenated waters.
Males can be distinguished from females by a black circle surrounded by orange near their tail fins. Their caudal fins turn a bright green during spawning seasons. Males create large nests and mate with multiple females. The eggs are deposited at night and guarded aggressively by males up to 9 days after hatching. Many waders have reported attacks from bowfins after unknowingly nearing an active nesting site.
6) Bluegill (Lepomis macrochirus)
Bluegills are compressed, deep-bodied fish that thrive in a variety of waters. Though they prefer warm and still habitats, bluegills regularly survive in extreme conditions and even slightly brackish water. This species is typically a smaller fish at around 7.5 inches as adults, but they have been known to reach as large as 16 inches within their brief lifespans.
Bluegills are named for the bluish dot on their cheek and gill covers, which quickly differentiates them from similar species. It is otherwise variable in color and markings, with body colors from dark blues to yellow and occasional vertical blue stripes. Breeding males tend to be more brightly colored and may even have orange throats. Another distinctive trait of bluegills is their small mouths. Due in part to this, they are almost exclusively insectivorous, with up to 50% of their diets consisting of midge fly larvae alone.
Bluegills school throughout the year and spawn in colonies of 50 or more males. Males of this prolific species typically fan out dish-shaped nests and aggressively defend their eggs until their fry can swim on their own.
Bluegills are major prey animals for larger species and closely associate with similar sunfish. Bluegills have a commensalistic relationship with mussels and often host mussel larvae in their gills.
7) Pumpkinseed sunfish (Lepomis gibbosus)
Lovingly referred to by their small fanbase as punkies, pumpkinseed sunfish are a bright and energetic species of sunfish. They are named for their platter-like bodies that are shaped like pumpkin seeds. They are brightly colored, with red, blue, and orange mottling along their yellow-based sides.
Pumpkinseed sunfish are easy to mistake for their close relative, the bluegill, whom they often school and interbreed with. Pumpkinseed sunfish can be distinguished from bluegills by the orange and blue wavy stripes on their cheeks and the crimson half-moon on their ear flaps.
They eat a variety of small prey from all levels of their given body of water, but most commonly school in the shallows of calm, highly vegetated waters. With a general lifespan of 6 – 8 years, pumpkinseed fish are short-lived and rarely grow past 4 – 6 inches in length. Some specimens have been known to be near a foot in length, but this is considered very uncommon.
Males nest in small colonies of 3 – 15 and form their nests by sweeping out oval-shaped holes in the sand. Females spawn in several of these nests before leaving, and males guard the eggs for around 11 days after hatching.
8) Rock bass (Ambloplites rupestris)
As its name would suggest, the rock bass is fond of swimming in lakes with rocky bottoms. It is not tolerant of silt or any other particles in its habitat and instead requires clear waters. It has a robust body and long mouth that extends midway through its bright red eye. This species has the potential to reach over 3 pounds but rarely surpasses 1.
They can be identified by the 6 spines on their anal fins and 12 on their dorsal fins. Unlike most sunfish, rock bass have a connected spiny and soft dorsal fin. Although they are typically olive or light brown with black spots, rock bass are able to rapidly change color to match their surroundings.
This species is secretive and sedentary, hiding in dark areas and weedy vegetation throughout the day. Rock bass school briefly during the winter, but disperse in the spring to spawn. Males are aggressive to one another throughout the spawning season and mate with several females. Males fiercely circle their nests to guard them, biting anything that gets in their way. During this time, they do not eat for days on end.
9) Largemouth bass (Micropterus salmoides)
Largemouth bass are a large, quickly growing species of sunfish that can reach as much as 16 inches long in 3 years alone! Due to their profound size and hardy nature, largemouth basses are typically top predators in whatever waters they dwell in.
It is a large, green fish with a dark blotchy strike along its mid-line and a white underbelly. As its name would suggest, the largemouth bass has a distinctly long mouth that reaches past its eye. It has a pair of prominent, divided dorsal fins, with a soft back fin and a spiny forefin.
Despite their large size and eager nature, largemouth basses don’t draw in many anglers to Mille Lacs. Compared to the more aggressive walleye and smallmouth bass, these warm-loving fish can’t compete in the cooler waters of Mille Lacs Lake.
At maturity, these top predators are capable of reaching upwards of 20 pounds, but as fry, they are often targeted by aggressive walleye, muskies, perches, and pikes. Young largemouth bass may school with similarly-sized fish for safety but are largely independent as adults.
Largemouth bass require plenty of vegetation and often stay close to fallen logs or other debris. These areas serve as resting spots, cover for ambushes, or a place to hide from predators.
10) Yellow perch (Perca flavescens)
Yellow perches are a significantly smaller relative of the walleye. Their adult size varies from 4 – 10 inches depending on the body of water they occupy, as yellow perches are prone to stunting in dense populations. Luckily, Mille Lacs Lake provides the open space, dense vegetation, and cool and shallow waters that yellow perches depend on to thrive.
Yellow perches are typically yellow or gold with 6 – 8 green stripes on their sides. An exception to this rule — a blue-black specimen — was caught in Mille Lacs Lake in 2015. This unusual coloring was caused by a rare mutation that results in excess blue pigmentation.
Because they are poor swimmers with low acceleration speeds, yellow perches rely on tightly organized schools of 50 – 200 fish to stay safe. These schools are organized by age and size, forming during dawn and breaking apart at dusk.
Spawning occurs in early spring, with mature females at 3 – 4 years and males at 2 – 3. Females release long ribbons of attached, mucous-bound eggs in shallow waters to be fertilized. These ribbons, which may be as long as seven feet depending on the size of the female, consist of 3000 – 100,000 eggs. Young yellow perches are not protected by their parents and begin to feed even before fully absorbing their yolk sacs.
11) Northern pike (Esox lucius)
Northern pikes are widespread, ambush predators that thrive in weedy shallows. They spend much of their days hiding in vegetation in an S position, ready to spring to action and strike at any would-be prey.
As a smaller relative of the massive muskie, northern pikes are similarly equipped with a duck-like beak full of sharp teeth on their jaws, the roof of its mouth, and its tongue. These teeth are constantly replaced, accounting for their voracious appetite and opportunistic feeding style. Northern pikes vary in their base color from dark greens to browns, but typically have rows of light spots along their sides and a creamy underbelly.
Unlike most other species, northern pikes typically become more active when waters become cool, making them a common catch for ice fishers. They spawn in the spring and deposit their eggs randomly onto vegetation. These eggs typically hatch in as few as two weeks but may take twice as long in colder waters.
12) Black crappie (Pomoxis nigromaculatus)
The black crappie is a silvery-green panfish with irregular black speckles and pots. Unlike most other panfish, it has a protruding lower jaw and long mouth. In addition to this unusual mouth, black crappies have a noticeably arched back and small heads. This species can be distinguished from the white crappie primarily by its 7 – 8 dorsal fin spines as opposed to the white crappie’s 6.
Although most black crappies grow to a moderate 6 – 12 inches in length, this species continues to grow throughout its life and can vary dramatically in size. Typically, black crappies grow rapidly until they are 2 – 4 years old and only live to be 7 years old in the wild. However, when given ample room, resources, and time, black crappies have been reported to grow up to 19 inches long.
Males of this schooling species build their nests together in large colonies on firm substrates. Rather than one male fertilizing the eggs of multiple females as in most species, female black crappies are prolific breeders which lay in several male nests. They may lay as many as 188,000 eggs per spawning season. Males continue to protect their nest for several days after their spawn hatch.
13) Green sunfish (Lepomis cyanellus)
Green sunfish are large, thick-bodied sunfish with green backs and sides. They may have black bars or blue mottling on their heads and sides, but specific coloration depends on the individual. Breeding males typically have white pelvic fins and most fish have a dark splotch on their dorsal fins.
They have very large mouths compared to similar species such as bluegills, which allow them to be aggressive feeders. Despite their large mouths, green sunfish are a small species that do not typically surpass one pound.
Their voracious eating habits combined with their hardiness in extreme and unstable conditions allow green sunfish to out-compete native species in bodies of water outside of their native range. Furthermore, green sunfish are an incredibly prolific species, spawning as often as every 8 – 10 days during their spawning season from May to August.
Multiple females lay clutches in the same nest, and each of these clutches is estimated to consist of up to 50,000 eggs. Males are dedicated caretakers who guard their eggs and regularly fan them to promote oxygenation. Due to their short lifespan of 6 – 8 years and tendency to be eaten by largemouth bass, green sunfish are largely kept in check in Mille Lacs Lake.
