Status, Distribution, and Conservation of Native Freshwater Fishes of Western North America

Great Plains Fishes Declining or Threatened with Extirpation in Montana, Wyoming, or Colorado

Wayne A. Hubert and Kelly M. Gordon

doi: https://doi.org/10.47886/9781888569896.ch1

ABSTRACT Of 55 fish species that were likely native to the Great Plains region of Montana, Wyoming, and Colorado, 33 (60%) species have been given some kind of conservation designation by at least one of the state fisheries management agencies because they are rare or in decline. The species with conservation designations were generally fishes that inhabit large rivers of the upper Missouri River drainage (14 species); live in small, cool- or clear-water streams (9 species); or reside in a wide array of habitats but occur at the edge of their ranges in individual states (10 species). Changes in riverine habitats due to construction of reservoirs on large rivers and introduction of exotic piscivorous fishes to reservoirs are major causes of decline of riverine species in the Great Plains region of Montana, Wyoming, and Colorado. Fishes that occur as disjunct, relict populations in small cool- or clear-water streams or at the periphery of their range in individual states are susceptible to local extirpations caused by habitat alterations and introductions of exotic piscivorous fishes but may have significant conservation value due to their genetic diversity. Given the large proportion of native Great Plains fishes that are declining or threatened with extirpation in individual states, a region-wide effort to maintain native fish assemblages is warranted.