Creek Chub (Semotilus atromaculatus) Conservation Status Review
Review Date = 04/08/2010
ScoreU - Unknown
ScoreF - 20,000-200,000 km squared (about 8,000-80,000 square miles)
Comment51,809 square kilometers based on Heritage Range Map area of 64,761 square kilometers, minus an estimated 20% of this range where they are introduced or in error (Fort Peck = introduced and Redwater River = error).
Area of Occupancy
ScoreE - 100-500 km squared (about 25,000-125,000 acres)
Comment171 square kilometers based on Heritage Range Maps and occupancy of 1% of landscape by streams and occupancy of 33% of sites surveyed
ScoreE - Relatively Stable (±25% change)
CommentEven though they have been impacted by grazing, exotic species, and some dewatering, prairie streams have probably been pretty stable in terms of water etc. since the arrival of Europeans within +/-25%
ScoreE - Stable. Population, range, area occupied, and/or number or condition of occurrences unchanged or remaining within ±10% fluctuation
CommentSince 1999, prairie fish surveys do not suggest decline as indicated by distribution data although this is not as sensitive to detecting decline as regular monitoring of a network of sites. The recent surveys have documented introductions in Fort Peck Lake.
ScoreF - Widespread, low-severity threat. Threat is of low severity but affects (or would affect) most or a significant portion of the population or area.
CommentOvergrazing, road crossings, dams, and exotic species (Northern Pike in particular) all represent threats.
SeverityLow - Low but nontrivial reduction of species population or reversible degradation or reduction of habitat in area affected, with recovery expected in 10-50 years.
CommentSpecies is capable of recovering quickly if suitable habitat is available. Northern Pike have heavy impacts during wet periods, however may be unable to persist in high numbers due to stochastic droughts and flooding so the Creek Chub may persist with No
ScopeModerate - 20-60% of total population or area affected
Comment75% of Creek Chub's range overlaps with the range of Northern Pike and Northern Pike are in about 60% of basins where Creek Chub are present. Intensive grazing is much more patchy, perhaps 5% of species range in Montana. So, overall, 50% of Creek Chub r
ImmediacyModerate - Threat is likely to be operational within 2-5 years.
ScoreC - Not Intrinsically Vulnerable. Species matures quickly, reproduces frequently, and/or has high fecundity such that populations recover quickly (< 5 years or 2 generations) from decreases in abundance; or species has high dispersal capability such that extirpated populations soon become reestablished through natural recolonization (unaided by humans).
CommentLongevity of 3-4 years
ScoreB - Narrow. Specialist. Specific habitat(s) or other abiotic and/or biotic factors (see above) are used or required by the Element, but these key requirements are common and within the generalized range of the species within the area of interest.
CommentSpecies requires gravel substrates for spawning. Carnivores that eat insects and other fish.
Raw Conservation Status Score
3.5 + 0.0 (area of occupancy) + 0.0 (environmental specificity) + 0.0 (short-term trend) + (threats) = 3.5