1. Minnesota Fish Identification and Characteristics
Shawn P. Linder
Grand Rapids High School
8/20/02

2. Problem Statement
What are the various characteristics of Minnesota Game Fish?

3. Learning Objectives
List and describe the five shapes of fish we look at to help us identify, and characterize them.
Identify the features that help identify a particular fish.
Positively identify the Minnesota game fish important for the economy of the state.
Understand important management information about each game fish covered.

4. K.Q. #1: What are the various shapes that classify MN game fish?
Rover Predators
Lie-in-wait Predators
Bottom Rovers
Deep Bodied
Eel Like

5. Rover Predators
Streamlined shape, pointed head, narrow caudal peduncle, always on the move.
e.g. Trout, Perch, Walleye

6. Lie-in-wait Predators
Explosive ambush predators. Body streamlined and elongate, torpedo like. Large caudal fin. Dorsal and anal fins far back. E.g. Northern, Musky

7. Bottom Rovers
Rover type body with flattened head, humped back, enlarged pectoral fins, E.g. Catfish, and Sturgeons.

8. Deep Bodied
Laterally flattened with a body depth at least 1/3 that of the length. Long dorsal and anal fin, pectoral fins high on the body with pelvic fins immediately below. Small mouth, large eyes, and short snout. Highly maneuverable, spines common. E.g. sunfish

9. Eel-like fish
Elongate bodies, blunt or wedge-shaped heads. Tapered, rounded tails.

11. K.Q. #2: What are the various fish within these fish shapes?

12. Rover Predators

13. Lake Trout

14. Lake Trout
They live primarily in Lake Superior and many of the deep, cold lakes of St. Louis, Lake, and Cook counties.
Lake trout only do well in lakes where water temperature does not exceed 18° C (65° F).
In Lake Superior, lake trout reach 45 in or more and can weigh (40 lbs).
Lake trout commonly reach the ages of 12-16, 25 years max.
Young lake trout first eat a diet of copepods and waterfleas. Then add opossum shrimp. Adult trout eat mostly fish including ciscoes, bloaters, smelt, and cottids.
Lake trout spawn in the fall, mostly in October though early November, when water temperature falls below 10° C (50° F).

15. Conservation and Management of Lake Trout
Lake trout used to be a very important commercial fish in the Great Lakes. A combination of predation by the sea lamprey, declines in the cisco populations (their main food), and overfishing caused their populations to go way down.

16. Rainbow Trout

17. Rainbow Trout
The rainbow trout is an introduced exotic species. It is native to the West Coast and some of the streams west of the Rocky Mountains.
Rainbow trout are introduced into many of Minnesota's streams and lakes in the northern 1/2 of state.
Inland rainbows are considerably smaller fish, 15 in long and 5.5lbs are lunkers. Most rainbows live for 3-4 years.
Young rainbow trout eat waterfleas and aquatic (water) insects, like caddisflies, mayflies, and midges. As they grow larger they include small fish, but continue to consume larval and adult insects.
Young rainbow trout often are eaten by a variety of piscivorous (fish-eating) fishes, such as sculpins, smallmouth bass, and larger trout.
Rainbow trout are usually years old when they spawn. Stream-dwelling rainbows migrate upstream to spawn. most spawn in the spring mostly in April in Minnesota.
Water temperatures must go above 5°C (41° F) and streams must rise (from rain) or they will not spawn.

18. Rainbow Trout Management and Conservation
Rainbow trout are probably the most important sport trout in Minnesota. They are a part of both coldwater lake and stream fisheries. More rainbows are stocked each year in Minnesota waters than any other trout or salmon.

19. Brook Trout

20. Brook Trout
Brook trout are native to headwaters and small streams of northeastern and southeastern Minnesota.
Their preferred habitat includes headwater spring ponds and small spring-fed streams that have cool, clear waters with sand and gravel bottoms.
How big a brook trout gets is dependent on what stream it comes from. The common size that anglers catch from heavily fished streams or lakes is 6 to 10in, but in areas of little fishing, they can get as large as 15 in.
In Minnesota streams, brook trout commonly live for 3-4 years.
The food of the young brook trout is mostly small insects. Older fish eat larger invertebrates including many types of aquatic insects. They also feed on minnows and other small fishes.
Brook trout have few aquatic predators because few predator fish live where they do. Larger trout, especially brown trout, eat smaller brook trout. They are more likely to be eaten by fish-eating birds such as herons, and kingfishers. Otters and snapping turtles also prey upon them.
Many brook trout females and some males reach sexual maturity in their first year of life. In Minnesota, the spawning season for the brook trout is normally in the autumn months, roughly October and November.

21. Brook Trout Management and Conservation
Brook trout are managed as a cold-water sport fish species.

22. Brown Trout

23. Brown Trout Brown trout are not native to North America.
Today, they occur in many of Minnesota's cold-water streams and lakes and also in Lake Superior.
Brown trout grow fairly rapidly until they reach maturity. Then they slow down a bit. In Minnesota, brown trout in long and lbs are fairly common in streams.
Because brown trout are somewhat resistant to the pressures of fishing, they can easily get to 5-7 years old.
The brown trout is a very active feeder and it eats a great variety of foods.
The main predators for this secretive trout are bigger trout and humans.
Most will spawn multiple years and often near the same place. Spawning habits and seasons are similar to the brook trout, except that brown trout take 3-4 years to mature.
Brown trout spawning season begins in October and goes into December. If there are no barriers as there are in many North Shore streams, brown trout swim up into headwater areas to spawn.

24. Brown Trout Management and Conservation
Brown trout is an exotic species that has become self-sustaining in some stream and maintained by repeated stocking in others.
Because of their good taste, size, fighting ability, and the challenge in getting them to bite, brown trout have become a favorite of many anglers.

25. Tulibee (Whitefish)

26. Whitefish
Naturally found in most northern Minnesota lakes. Once an important species in Lake Superior.
Reach a weight of 5 pounds, avg of 3-4.
Spawning happens in the fall only at night, eggs are not cared for and hatch the following spring.
Feed on plankton, then aquatic larva and insects.

27. Whitefish Management and Conservation
Once considered an important species now replaced, by smelt and lake trout in northeast Minnesota.

28. Walleye

29. Walleye
Walleye occur in all major drainages of Minnesota, but they were probably introduced in the southwestern part of the state.
Walleye favor clear, cool and calm waters, but can occupy turbid (cloudy. When water temperatures go over 22° C (72° F), walleye head for deeper, cooler water.
Grows to 26 in, and catches in range are common. Walleye in these lakes often weigh 6-9 lbs, with the rare fish reaching nearly 15 lb.
The maximum age of walleye is in question, but most believe its 20 years, but commonly 3-4 years due to fishing pressure.
Walleye are piscivores (fish-eaters) and will eat any species of fish they can catch and swallow. Yellow perch and many species of minnows.
Walleye spawn in April and early-May soon after ice-out and water temperatures in the shallows reach 4-7° C (40-45° F).

30. Walleye Management and Conservation
The walleye is the official state fish of Minnesota as well as the state's most popular sport fish. More people go fishing on the opening day of walleye season than any other day of the year.
The Minnesota Department of Natural Resources raises a huge number of walleye every year for stocking. Stocking efforts vary greatly across the state and often are done cooperatively with various Lake Associations (groups of property owners around a given lake). Many of these cooperative efforts have been very successful.
Minnesota's premiere walleye lakes include Lake of the Woods, Lake Mille Lacs, Leech Lake, Lake Winnibigoshish, Otter Tail Lake, Gull Lake, Lake Saganaga, and others. Large populations also exist in the Rainy, St. Louis, St. Croix, and Mississippi rivers.

31. Sauger

32. Sauger Similar to the Walleye but on a smaller scale.
Found mostly in Lake of Woods, and large rivers.
Avg weight of 1 ½ pounds.

33. Yellow Perch

34. Yellow Perch Yellow perch occur in all major drainages of Minnesota.
Yellow perch are more abundant in lakes and backwaters of large rivers than they are in swift-flowing streams.
Female yellow perch grow faster and reach an overall bigger size than males do. Some females get to 15 in and weigh over 1 lb.
Yellow perch typically live for 7-9 years. The oldest known age is 13.
Larval yellow perch commonly eat copepods, waterfleas, and other small crustaceans. Juveniles eat aquatic insect larvae and larval fish. Adult perch eat small fish, crayfish, leeches, and snails in their diet.
The yellow perch is a common prey to many piscivorous (fish-eating) fishes, mostly Walleye.
Yellow perch spawn fairly early, soon after ice-out in April and early May. Water temperature only needs to reach 7° C (45° F) to induce spawning.

35. Yellow Perch Management and Conservation
Yellow perch are usually not the sport fish most anglers try for, but they are one that most anglers catch.
They are especially common in the ice-anglers bucket. Yellow perch flesh is firm and very good tasting.
One of the problems with perch is that they have a tendency to overpopulate, especially in lakes where too many of the larger sport fish have been harvested.

36. Rainbow Smelt

37. Rainbow Smelt
Accidentally introduced into Lake Michigan, spread throughout great lakes.
“Smelting” occurs every spring, where anglers have a week to ten days before the run is over. This best done at night.
DNR is trying to prevent the spread on smelt in land lakes.

38. Lie-in-Wait Predators

39. Northern Pike

40. Northern Pike
Northern pike occur in all drainages of Minnesota, but are most abundant in central and northern Minnesota east of the prairie.
They inhabit lakes, ponds, streams, and rivers and are most common in weedy areas with cool to warm, slow-moving water.
Northerns grow fast first few years of life (14-26 in) long after their first two growing seasons. Max size of 40 inches and 40 pounds.
Northerns typically live for 6-9 years, but there are records of a few who reached the ripe old age of 25. Some captive northerns have lived for 75 years!
Most often it lies still in the weeds waiting for a fish to swim by. Then it lunges quickly and grabs the startled fish in its huge, toothy jaws.
Silver lampreys and sea lampreys in Lake Superior attack large adult pike, but the largest predators for them are humans and bigger northerns.
Northerns spawn in April or early May as soon as the ice melts. They move up into small streams during the night hours or select shallow, flooded marshlands or grassy lake margins as their spawning sites.

41. Northern Pike Management and Conservation
Northern pike are one of Minnesota's premier sport fish. They strike on live bait and many kinds of crank-baits. Hook a 2.3 kg (5-lb) northern and you're in for a fight! Even small northerns provide a tussle if you are fishing with light tackle.
Northerns are a tasty fish, but it is a good idea to learn how to remove their "Y" bones as you fillet them.

42. Muskellunge (Musky)

43. Muskellunge
In Minnesota, the muskellunge is native to lake and rivers in the Rainy and upper Mississippi river drainages, and the lower Mississippi River south to Lake Pepin.
Muskellunge normally live in lakes and slow-moving rivers with clear water and numerous underwater weed beds.
Lunker Muskies grow to in long and weigh lbs.
One musky from Canada was estimated to be 30 years old.
As do large northerns, adult muskies supplement their fish dinners with the occasional duck or muskrat.
The musky spawning season is in the spring (April or May) about 2 weeks or more later than the northern pike season.
As with the northerns, newly hatched muskies attach themselves to the vegetation using the adhesive organ on their heads. Here they develop their mouths and fins over another 1-2 weeks before they swim free and begin to feed.

44. Musky Management and Conservation
The so-called "aristocrat of trophy fishes" is the largest sport fish in Minnesota. It is called the "aristocrat" because of its huge size and because it is very difficult to catch a musky. Many anglers try, but few succeed. Most musky anglers never land their trophy. That is the great appeal.
They are especially well known from Lake of the Woods, Rainy Lake, Leech Lake, Cass Lake, Lake Winnibigoshish, and some of the smaller lakes near Park Rapids and Grand Rapids.
They have been planted in many lakes and some rivers all over the state.

45. Long-Nose Gar

46. Long-Nose Gar
The distribution for the longnose gar in Minnesota is limited because of its preference for warmer water. It lives in the lower Mississippi, St. Croix, and Minnesota rivers and some of their tributaries.
The longnose gar lives in large rivers that have backwaters with little to no current and in weedy, floodplain lakes.
By gulping air at the surface, gar can live in hot, shallow water where most other fish cannot (because there isn't enough oxygen in it).
Large adults easily grow to 3 ft or more. They can weigh 6-10 lbs.
They eat fish of all sizes and all kinds. Often gar will lie near the surface of the water barely moving and wait for schools of small fish to swim by. With a quick sideways snap of the head, a gar grabs one or more fish in its long, many-toothed jaws. Gar also catch their prey by swimming up along side of them.
Humans do not eat this poor tasting fish. It eggs are even said to be poisonous.
Female longnose gar can be mature at 4 years old, males at 3. Their spawning season in Minnesota is probably late May into June when water temperatures are 19° C (67° F) or more.

47. Bottom Rovers

48. German Carp

49. German Carp
Native to Asia, accidentally released into public waters from a hatchery.
It’s a rough fish and destroys natural fish habitats.
Large amounts of money are used to control these fish (gates, and rotenone).
Carp reach as much as 20 pounds.
There are no limits on this fish and can be taken in many ways.

50. White Sucker

51. White Sucker
The white sucker is one of Minnesota's most common fish, and it is the most widely spread distributed sucker in Minnesota.
White suckers are benthic (bottom dwellers) and live in all kinds of lakes and streams from clean, stream-fed brooks to slow-moving, turbid (cloudy) rivers.
White suckers in Minnesota normally grow to about 300 mm (20 in) and weigh in at about kg (2-3 lbs).
White suckers typically live for about years.
Their diet is highly variable and depends on where they've been feeding.
The spawning season in Minnesota for the white sucker begins in April and goes into early May.

52. Lake Sturgeon

53. Lake Sturgeon
They are present in limited numbers in the lower Mississippi, St. Croix, Minnesota, Red, and Rainy rivers.
In rivers, lake sturgeons tend to live in the deepest parts of the channels or in deep pools.
Many lake sturgeon reach over 50 kg (over 100 lbs). The big ones weigh in at over 100 kg (220 lbs) and can be over 2 m (6.5 ft) long.
We know of several that were over 80 years old when captured.
Adults suck their food up from the lake or river bottom.
The spawning season for lake sturgeon in Minnesota spans the months of April, May, and sometimes June. Males do not reach sexual maturity until they are 20 years old, and females are usually 25 years old before they spawn for the first time. Females only spawn every 4 to 6 years, while the males usually spawn every other year.

54. Lake Sturgeon Management and Conservation
Lake sturgeons currently are listed as a species of special concern. Overfishing, habitat alteration, and pollution turned this species from one of our most abundant large fishes into one of our rarest.
Lake sturgeon have been reintroduced to the Red River system, and recovery of populations in the upper St. Croix and Rainy river systems has been reasonably good.
Poor water quality and migration barriers (locks and dams) continue to prevent recovery in the lower Mississippi River.
At the end of the 1800s, caviar (eggs) of this species were in high demand.

55. Channel Catfish

56. Channel Catfish
Channel catfish live in many of Minnesota's medium to large rivers and their interconnecting lakes.
Channel catfish occupy a variety of habitats from clear, rocky riffles to deep, muddy pools in turbid (cloudy) rivers.
In Minnesota channel catfish commonly reach in and weigh in at 3 to 5 lbs, but they can get as big as 40 lbs.
This fish normally lives to be about 5-8 years old.
They consume a huge variety of foods, including aquatic insect larvae, crayfish, clams, green algae, water plants, worms, and many kinds of small fishes.
Channel catfish spawn mostly in May and June in Minnesota when the water temperature reaches 24° C (75° F).

57. Black Bullhead

58. Black Bullhead
Black bullheads are common throughout Minnesota, but they are most common in the southern half of the state.
They prefer slow moving, turbid water that have soft bottoms made up of mud and sand, sometimes with gravel mixed in.
6-10 inches, or two pounds.
This bottom dweller is considered a scavenger (eats dead things) and an opportunist (eats whatever comes its way).
Spawning starts in late April and goes through to early June, when water temperatures are about 68-70° F.

59. Deep Bodied (Pan Fish)

60. Blue Gill

61. Blue Gill
The bluegill lives throughout Minnesota, but it is most abundant in the central area of the state.
This popular pan fish lives in the shallows of many lakes and ponds.
They can easily grow to a range of inches in 3 years and up to 8 inches in 7-9 years.
The adult bluegill's diet is mostly aquatic insect larvae (such as mayflies, caddisflies, and dragonflies), but also includes crayfish, leeches, snails, and sometimes small fish.
Mostly larger predatory fish, such as largemouth bass, northern pike, yellow perch, and even bigger bluegill, target the young and small adult bluegills for a food source.
The spawning season for the bluegill starts in late May and goes into early August, (peak spawning is in June) at water temperatures of 19-27° C (67-80° F).

62. Blue Gill Management and Conservation
The bluegill is the most sought-after sunfish in Minnesota.
All total there are probably more bluegills caught by anglers in Minnesota than any other species of fish.
We do little to manage this species, except in some lakes where adult sizes are small.
In these lakes we try to reduce the population size by increasing the number of fish caught by anglers. It usually doesn't work.

63. Pumpkin Seed

64. Rock Bass

65. Rock Bass Found throughout Minnesota
Found in shallow weeding areas and weed lines.
Reaches 10 inches, 2 pounds
Eats mostly insects, snails, and small fishes.
Attractive to young anglers for fast action.
Rock bass spawn in May and June.

66. Largemouth Bass

67. Largemouth Bass
Largemouth bass occur in all of the major drainages of Minnesota, but are most common in the central to north-central portions of the state.
True largemouth anglers will tell you there are plenty of (5-lb) fish in our lakes, but rarely does one end up in the boat.
A largemouth bass can live up to 15 years, but fish over 10 years old are rare.
Largemouth consume many species of fishes (including sunfishes, yellow perch, and minnows), crayfish, surface insects, and frogs.
Largemouth bass spawn mostly in May and June in Minnesota when water temperature goes above 15.5° C (about 60° F).

68. Largemouth Bass Management and Conservation
Largemouth bass is one of the top 3 warm-water sportfish in Minnesota.
This species sometimes is planted in ponds or small lakes to get a population going.
The usual management strategy for most populations is to protect bass from angling during at least part of the spawning season and limit the number of bass that can be taken daily.

69. Smallmouth Bass

70. Smallmouth Bass
The most popular sportfish in the B.W. C.A. is actually an exotic species. But its native to MN.
Smallmouth bass prefer clear, strong-flowing streams and rivers and medium-sized clear lakes with gravel or boulder shores.
Many anglers catch smallmouth that weigh 2-4 lbs. in Minnesota years old
Eat mostly fish (darters, minnows, yellow perch, sunfishes, and others) and crayfish.
Spawn mostly from the middle of May through the end of June when water temperature exceeds 15.5° C (about 60° F).

71. Smallmouth Bass Management and Conservation
One of the top three warm-water sportfish in Minnesota (largemouth and northern pike are the other two).
This species has been planted in many lakes and streams over the years.
The principal management strategy is to protect it during the early spawning season and limit its daily catch.

72. Black Crappie

73. Black Crappie
They are most abundant in the central portion of the state and least abundant in the deep, rocky lakes of the Arrowhead region.
They prefer clear, calm, warm water with lots of vegetation.
(10-12 in) and about (1-2 lbs). can live for 7-9 years.
Black crappies continue to consume insect larvae, but minnows, small bluegill, and small yellow perch become their major prey.
Black crappies spawn in May and June in Minnesota, when the water temperature goes above 15° C (59° F).

74. Black Crappie Management and Conservation
Both black and white crappies are much sought after panfish.
More anglers catch black crappies than white because black crappies are more abundant and widespread.
Crappies are notorious for their short feeding frenzies, often in the early morning or late evening. At these times, anglers can get a bite almost as fast as they can rebait their hooks.

75. White Crappie

76. Eel-Like Fish

77. American Eel

78. American Eel
American eels are found mostly in the lower Mississippi River and its larger tributaries, such as the St. Croix and Minnesota rivers.
Typically 3 feet long, 2-4 pounds.
We do not know exactly how long American eels live, but females spend years before they become mature and return to the oceans. They die after breeding once. One American eel lived in captivity for 88 years.
American eels do most of their feeding at night and are exclusively meat eaters.
Once the female eel has reached maturity (after years in the freshwater streams and lakes), she starts back down the main river (Mississippi River or St. Lawrence Seaway) towards the ocean to spawn.
This species has no special concern status in Minnesota.

79. Sea Lamprey

80. Sea Lamprey Evil Non-Indigenous Fish Parasite of Northerns and Lakers
Spawn in tributaries on Lake Superior in April and May.
3-4 inches long, ¼ pound. Live only 2-3 years.

81. Bowfin (Dog Fish)

82. Bowfin (Dog Fish)
Relative to Burbot, but prefers the warmer water lakes.

83. Burbot (Eel Pout)

84. Burbot (Eel Pout)
The burbot is a cold-water species and can be found in most of Minnesota's northern lakes and rivers, including Lake Superior.
Burbot are not present in waters that typically exceed 21° C (69° F) during the summer.
Typically they are less than 28 in and weigh 6- 8 lbs.
Since this fish lives a secretive life, it easily reaches the ripe old age of years.
They eat mostly other fish.
The spawning season for this fish is very unusual. It spawns during mid-winter into early spring, before the ice is off the water. Burbot spawn in pairs or sometimes in a ball of many fish.

85. Eel Pout Management and Conservation
Burbot do not have special conservation status in Minnesota and are not actively managed. However, they are a big winter hit in Walker, Minnesota. Each year the city hosts the International Eelpout Festival on Leech Lake. More then 2,000 anglers try to bring the biggest burbot up through the ice.
During the ice-fishing season, when they are very active, burbot often are caught by anglers fishing for walleyes. Some anglers won't touch a burbot. They cut their lines and discard the fish not realizing that burbot is a tasty relative of the Atlantic cod.