Fish

Largescale suckers (Catostomus macrocheilus) on a riverbottom.

NPS

Overview

The historic assemblage of fish species in Glacier National Park is restricted in number due to the relatively recent withdrawal of continental glaciers from the region. The human urge to tinker with natural systems is no better illustrated than in the park fishery, which has been radically changed by human manipulations. Lake trout (also called mackinaw), historically found only in park waters draining to Hudson Bay, now occur in most of of the large lakes west of the Continental Divide. However, there is no evidence that non-native lake trout were directly stocked in park waters. They apparently became established in several of the park's west side lakes through migration from the lower Flathead River system where they were introduced during the early 1900s.

Several other species were directly introduced into park waters: rainbow trout, brook trout, Yellowstone cutthroat trout, kokanee, lake whitefish and grayling.

Native to the park's west side: Bull trout (Federally listed as a "threatened" species), westslope cutthroat trout, largescale suckers, northern pikeminnow, redside shiners, peamouth, and several species of sculpins.

Several high, pristine fishless lakes in the park have been stocked with non-native sportfish species. The idea was to provide increased opportunities for recreational angling. During earlier periods there was little appreciation for the integrity and complexity of aquatic systems that evolved over thousands of years. Fish stocking in the region began shortly after the turn of the century and continued until 1971.

Introduced fish bring new diseases, alter the composition of plankton communities, interrupt food web dynamics, and prey on native fish. Research has shown that changes in zooplankton communities generally occur when fish are introduced into previously fishless waters. Non-native Lake trout pose a grave threat to native bull trout, westslope cutthroat trout and other native species in several park lakes. There are still a few pristine lakes and streams in the park that remain strongholds for genetically untainted native fish species.

Learn More:

For a statewide species list and photos to help with identification, check out the Montana Field Guide. Learn more about fishing regulations in Glacier on this page.

Learn more about fish, fishing, and the work the National Park Service does to conserve aquatic habitats nationwide.

 

Full Species List

 

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Species Attribute Definitions

Definitions

Occurrence

Occurrence values are defined below. One or more Occurrence Tags may be associated with each Occurrence value.

Present: Species occurs in park; current, reliable evidence available.

Probably Present: High confidence species occurs in park but current, verified evidence needed.

Unconfirmed: Species is attributed to park but evidence is weak or absent.

Not In Park: Species is not known to occur in park.

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Occurrence Tags

Adjacent: Species is known to occur in areas near to or contiguous with park boundaries.

False Report: Species was reported to occur within the park, but current evidence indicates the report was based on misidentification, a taxonomic concept no longer accepted, or other similar problem of error or interpretation.

Historical: Species' historical occurrence in park is documented. Assigned based on judgment as opposed to determination based on age of the most recent evidence.

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Abundance

Abundant:

• Animals: May be seen daily, in suitable habitat and season, and counted in relatively large numbers.
• Plants: Large number of individuals; wide ecological amplitude or occurring in habitats covering a large portion of the park.

Common:

• Animals: May be seen daily, in suitable habitat and season, but not in large numbers.
• Plants: Large numbers of individuals predictably occurring in commonly encountered habitats but not those covering a large portion of the park.

Uncommon:

• Animals: Likely to be seen monthly in appropriate habitat and season. May be locally common.
• Plants: Few to moderate numbers of individuals; occurring either sporadically in commonly encountered habitats or in uncommon habitats.

Rare:

• Animals: Present, but usually seen only a few times each year.
• Plants: Few individuals, usually restricted to small areas of rare habitat.

Occasional:

• Animals: Occurs in the park at least once every few years, varying in numbers, but not necessarily every year.
• Plants: Abundance variable from year to year (e.g., desert plants).

Unknown: Abundance unknown

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Nativeness

Native: Species naturally occurs in park or region.

Non-native: Species occurs on park lands as a result of deliberate or accidental human activities.

Unknown: Nativeness status is unknown or ambiguous.

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List Differences

The Checklist contains only those species that are designated as "present" or "probably present" in the park.

The Full List includes all the checklist species in addition to species that are unconfirmed, historically detected, or incorrectly reported as being found in the park. The full list also contains species that are "in review" because their status in the park hasn't been fully determined. Additional details about the status of each species is included in the full list.

The checklist will almost always contain fewer species than the full list.

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Species attribute definitions

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