Different fish species respond differently to water quality and habitat changes within a lake environment. For example, some are sensitive to poor water quality while others thrive in those conditions. Some need clear water to see and capture their prey while others have the ability to eat a wide range of items. Some depend on specific habitat such as aquatic plants or crevices in rocks along the bottom of the lake for protection from predators. Each species serves a unique role in a lake environment, and depending on that role, their presence or absence in a sample can provide valuable information about the health of a lake.
The following dropdown menus provide more information about each group of fish species that is considered in Minnesota’s fish-based index of biological integrity (IBI) for lakes. For some species, additional information can also be found on the fishes of Minnesota webpage (denoted with an *), Rare Species Guide webpage (denoted with a †), or invasive aquatic animals webpage (denoted with a ‡).
Click on topic below to reveal more information. Click again to hide.
- Intolerant species
Click to enlarge
Example of an intolerant species (i.e., Burbot).
Description:
Intolerant fish species are those that are most sensitive to decreases in water quality and habitat alterations and are typically the first to disappear from degraded lakes. Twenty-five species are classified as intolerant in Minnesota’s lake fish IBI based on their responses to various measures of environmental degradation. A higher number and abundance of intolerant species is associated with higher quality habitat in some lake types. Specifically, the number of intolerant species present in a lake is one measurement included in three of Minnesota’s four lake IBIs for the following lake types: deep lakes with complex shaped shorelines, moderately deep lakes with rounder shorelines, and moderately shallow, heavily vegetated lakes. The count of intolerant species relative to others sampled by seining and electrofishing and the presence of an intolerant species sampled in gill nets are also included in two IBIs for the following lake types: deep lakes with complex shaped shorelines and moderately deep lakes with rounder shorelines.Intolerant species in Minnesota lakes:
- Banded Killifish
- Blackchin Shiner
- Blacknose Shiner
- Brook Trout*
- Brown Trout*
- Burbot*
- Chestnut Lamprey (Ammocoete)
- Cisco*
- Greater Redhorse
- Iowa Darter
- Lake Sturgeon†
- Lake Trout*
- Lake Whitefish
- Least Darter†
- Logperch
- Longnose Dace
- Mimic Shiner
- Mottled Sculpin
- Muskellunge*
- Northern Sunfish†
- Pugnose Shiner†
- Rainbow Trout*
- Rock Bass
- Slimy Sculpin
- Smallmouth Bass*
- Tolerant species
Click to enlarge
Example of a tolerant species
(i.e., Common Carp).Description:
Tolerant fish species are those that thrive in lakes typically characterized as having poor water quality. Tolerant species are also sometimes sampled in pristine lakes, but are generally found in lower numbers in lakes with higher quality habitat. Six species are classified as tolerant in Minnesota’s lake fish IBI based on their responses to various measures of environmental degradation. A higher number and abundance of tolerant species is associated with lower quality habitat in lakes. Specifically, the number of species present in a lake that are tolerant is one measurement included in all four of Minnesota’s lake IBIs. The amount of weight from tolerant species relative to others sampled in trap nets is also included in all four IBIs.Tolerant species in Minnesota lakes:
- Bigmouth Buffalo*
- Black Bullhead*
- Common Carp
- Fathead Minnow
- Green Sunfish
- Orangespotted Sunfish
- Insectivore species
Click to enlarge
Example of an insectivore species
(i.e., Pumpkinseed). Photo by
Gretchen Hansen.Description:
Insectivore fish species are those that primarily rely on their sight and clear water to feed mainly on insects. Fifty-eight species are classified as insectivores in Minnesota’s lake fish IBI based on their preferred prey items. A higher number of insectivore species is associated with higher quality habitat in some lake types. Specifically, the number of species present in a lake that are insectivores is one measurement included in two of Minnesota’s four lake IBIs for the following lake types: deep lakes with complex shaped shorelines and shallow lakes. The amount of weight from insectivore species relative to others sampled in trap nets is also included in all four IBIs.Insectivore species in Minnesota lakes:
- Banded Killifish
- Bigmouth Buffalo*
- Bigmouth Shiner
- Blackchin Shiner
- Blacknose Dace
- Blacknose Shiner
- Blackside Darter
- Bluegill*
- Brook Silverside
- Brook Stickleback
- Brook Trout*
- Central Mudminnow
- Cisco*
- Common Shiner
- Creek Chub
- Emerald Shiner
- Fantail Darter
- Finescale Dace
- Freshwater Drum*
- Gilt Darter†
- Golden Redhorse
- Golden Shiner
- Greater Redhorse
- Green Sunfish
- Hornyhead Chub
- Iowa Darter
- Johnny Darter
- Lake Sturgeon†
- Lake Whitefish
- Least Darter†
- Logperch
- Longnose Dace
- Longnose Sucker
- Mimic Shiner
- Mottled Sculpin
- Northern Hog Sucker
- Northern Sunfish†
- Orangespotted Sunfish
- Pearl Dace
- Pugnose Shiner†
- Pumpkinseed
- Rainbow Darter
- Rainbow Smelt
- Rainbow Trout*
- River Redhorse
- Sand Shiner
- Shorthead Redhorse
- Silver Redhorse
- Slenderhead Darter
- Slimy Sculpin
- Smallmouth Buffalo
- Spotfin Shiner
- Spottail Shiner
- Stonecat
- Tadpole Madtom
- Trout-Perch
- Yellow Bass†
- Yellow Perch*
- Omnivore species
Click to enlarge
Example of an omnivore species
(i.e., Common Carp).Description:
Omnivore fish species are those that feed on a wide variety of plant and animal items and therefore may not be as dependent on their eyesight or clear water. Eleven species are classified as omnivores in Minnesota’s lake fish IBI based on their preferred prey items. A higher number and abundance of omnivore species is associated with lower quality habitat in some lake types. Specifically, the number of species present in a lake that are omnivores is one measurement included in three of Minnesota’s four lake IBIs for the following lake types: deep lakes with complex shaped shorelines, moderately deep lakes with rounder shorelines, and moderately shallow, heavily vegetated lakes. The amount of weight from omnivore species relative to others sampled in trap nets is also included in three IBIs for the following lake types: deep lakes with complex shaped shorelines, moderately deep lakes with rounder shorelines, and moderately shallow, heavily vegetated lakes.Omnivore species in Minnesota lakes:
- Black Bullhead*
- Bluntnose Minnow
- Brown Bullhead*
- Common Carp
- Fathead Minnow
- Goldfish
- Pugnose Minnow
- Quillback
- River Carpsucker
- White Sucker*
- Yellow Bullhead*
- Top carnivore species
Click to enlarge
Example of a top carnivore species
(i.e., Muskellunge).Description:
Top carnivore fish species are those that primarily feed on other fish species. Twenty-three species are classified as top carnivores in Minnesota’s lake fish IBI based on their preferred prey items. A higher abundance of top carnivores is associated with higher quality habitat in lakes. Specifically, the amount of weight from top carnivore species relative to others sampled in gill nets is one measurement included in all four of Minnesota’s lake IBIs.Top carnivore species in Minnesota lakes:
- Black Crappie*
- Bowfin*
- Brook Trout*
- Brown Trout*
- Burbot*
- Channel Catfish*
- Chestnut Lamprey (Adult)
- Flathead Catfish*
- Lake Trout
- Largemouth Bass*
- Longnose Gar*
- Muskellunge*
- Northern Pike*
- Rainbow Trout*
- Rock Bass
- Sauger*
- Shortnose Gar
- Smallmouth Bass*
- Splake*
- Tiger Muskellunge*
- Walleye*
- White Bass
- White Crappie*
- Small benthic-dwelling species
Click to enlarge
Example of a small benthic-dwelling
species (i.e., Johnny Darter).Description:
Small benthic-dwelling fish species are those considered to be small-bodied non-game species dependent on specific bottom types such as boulders and gravel for cover. Seventeen species are classified as small benthic-dwelling species in Minnesota’s lake fish IBI based on their preferred habitat. A higher number and abundance of small benthic-dwelling species is associated with higher quality habitat in some lake types. Specifically, the number of species present in a lake that are small benthic-dwelling is one measurement included in three of Minnesota’s four lake IBIs for the following lake types: deep lakes with complex shaped shorelines, moderately deep lakes with rounder shorelines, and shallow lakes. The count of small benthic-dwelling species relative to others sampled by seining and electrofishing is also included in two IBIs for the following lake types: deep lakes with complex shaped shorelines and moderately deep lakes with rounder shorelines.Small benthic-dwelling species in Minnesota lakes:
- Blacknose Dace
- Blackside Darter
- Central Stoneroller
- Fantail Darter
- Gilt Darter†
- Iowa Darter
- Johnny Darter
- Least Darter†
- Logperch
- Longnose Dace
- Mottled Sculpin
- Rainbow Darter
- Slenderhead Darter
- Slimy Sculpin
- Stonecat
- Tadpole Madtom
- Trout-Perch
- Vegetation-dwelling species
Click to enlarge
Example of a vegetation-dwelling species
(i.e., Bowfin).Description:
Vegetation-dwelling fish species are those that are dependent on aquatic plants such as bulrushes, pondweeds, and lilies for cover. Fifteen species are classified as vegetation-dwelling species in Minnesota’s lake fish IBI based on their preferred habitat. A higher number and abundance of vegetation-dwelling species is associated with higher quality habitat in some lake types. Specifically, the number of species present in a lake that are vegetation-dwelling is one measurement included in three of Minnesota’s four lake IBIs for the following lake types: deep lakes with complex shaped shorelines, moderately deep lakes with rounder shorelines, and shallow lakes. The count of vegetation-dwelling species relative to others sampled by seining and electrofishing is also included in one IBI for the following lake type: shallow lakes.Vegetation-dwelling species in Minnesota lakes:
- Banded Killifish
- Blackchin Shiner
- Blacknose Shiner
- Bowfin*
- Central Mudminnow
- Iowa Darter
- Least Darter†
- Mimic Shiner
- Muskellunge*
- Northern Pike*
- Northern Redbelly Dace
- Pugnose Minnow
- Pugnose Shiner†
- Tadpole Madtom
- Weed Shiner
- Cyprinid species
Click to enlarge
Example of a cyprinid species
(i.e., Blacknose and Blackchin shiners).Description:
Cyprinid fish species are those that are classified as shiners or minnows. Twenty-three species are classified as cyprinids in Minnesota’s lake fish IBI. A higher number of cyprinid species is associated with higher quality habitat in some lake types. Specifically, the number of species present in a lake that are cyprinids is one measurement included in one of Minnesota’s four lake IBIs for the following lake type: deep lakes with complex shaped shorelines.Cyprinid species in Minnesota lakes:
- Bigmouth Shiner
- Blackchin Shiner
- Blacknose Dace
- Blacknose Shiner
- Bluntnose Minnow
- Brassy Minnow
- Central Stoneroller
- Common Shiner
- Creek Chub
- Emerald Shiner
- Fathead Minnow
- Finescale Dace
- Golden Shiner
- Hornyhead Chub
- Longnose Dace
- Mimic Shiner
- Northern Redbelly Dace
- Pearl Dace
- Pugnose Minnow
- Pugnose Shiner†
- Sand Shiner
- Spotfin Shiner
- Spottail Shiner
- Weed Shiner
- Native and non-native species
Click to enlarge
Example of a non-native species
(i.e., Brown Trout).Description:
Native fish species are those that would naturally be found in lakes throughout Minnesota, whereas non-native fish species are those that would not naturally be found but may have been introduced into Minnesota lakes, either intentionally or unintentionally. Eighty-eight native species have been sampled during fish IBI surveys in lakes, whereas seven non-native species have been sampled. A higher number of native species is associated with higher quality habitat in some lake types. Therefore, excluding non-native species, the number of species present in a lake is one measurement included in one of four IBIs for the following lake type: deep lakes with complex shorelines.Non-native species in Minnesota lakes:
- Brown Trout*
- Common Carp‡
- Goldfish
- Rainbow Smelt
- Rainbow Trout*
- Splake*
- Tiger Muskellunge*
