Something’s Fishy: A Genetic Investigations Of Sculpin Species In Western Montana

Scientific Disciplines
Biological Sciences - Aquatic
Keywords
USDA Forest Service
Montana
Rocky Mountain Research Station
cottus
sculpin
mitochondrial DNA
Authors
Years
Volumes
Volume 17, No. 1-4

Something’s fishy: a genetic investigations of sculpin 
Species in western montana
Kristy Pilgrim,* USDA Forest Service, Rocky Mountain Research Station, 800 E. Beckwith 
Missoula, Montana 59801, kpilgrim@fs.fed.us
Michael Young, USDA Forest Service, Rocky Mountain Research Station, 800 E. Beckwith 
Missoula, Montana 59801
Kevin McKelvey, USDA Forest Service, Rocky Mountain Research Station, 800 E. Beckwith 
Missoula, Montana 59801
David Schmetterling, Montana Fish Wildlife and Parks
Susie Adams, USDA Forest Service,  Southern Research Station
Michael K. Schwartz, USDA Forest Service, Rocky Mountain Research Station, 800 E. Beckwith 
Missoula, Montana 59801
Sculpin (Cottus spp.) are small, cryptic, bottom-dwelling fish native to cool and 
coldwater systems throughout North America. Although three species of primarily stream-
dwelling sculpin are thought to occur in Montana (one of which is a species of concern), their 
taxonomy, distribution, and origin are not well understood. In western Montana, the present 
distribution of sculpin species may have been shaped by both historical events, e.g., the 
Columbian Ice Sheet, and contemporary landscape changes (passage barriers, climate change, 
pollution, etc.). To evaluate sculpin presence, and species diversity, we analyzed sculpins from 
river drainages throughout western Montana—the Clark Fork, Blackfoot, Flathead, Bitterroot, 
Kootenai, Gallatin, Madison, and Missouri—east and west of the Continental Divide. We 
analyzed 135 samples at the mitochondrial DNA COXI gene and at 11 microsatellite DNA 
loci. Preliminary results of genetic analysis suggest the presence of four distinct species 
with hybridization among three of the species in some locations. Hybridization led to 
uncertainty in species designations based on morphology, but even genetically pure fish were 
occasionally misidentified.  One species may represent an undescribed taxon that is limited in 
its distribution to the St. Regis drainage, although its relation to sculpin in Idaho is unknown. 
A second species, previously thought to be Cottus bairdii, is distinct from that taxon and is 
distributed on both sides of the Continental Divide.