Journal Article

Status and Conservation of the Rio Grande Silvery Minnow, Hybognathus Amarus

URL: https://webapps.usgs.gov/mrgescp/documents/Bestegen%20and%20Platania_1991_Status%20and%20Conservation%20of%20the%20RGSM%2C%20Hybognathus%20Amarus.pdf

Date: 1991/06/01

Author(s): Bestgen K.R., Platania S.P.

Publication: The Southwestern Naturalist, v. 36(2), p. 225-232

Abstract:

The Rio Grande silvery minnow (Hybognathus amarus) was formerly one of the most widespread and abundant species in the Rio Grande basin of New Mexico, Texas, and Mexico, but recent surveys indicated that its current range has been much reduced. In the Pecos River, New Mexico, H. amarus had declined by 1968, coincident with establishment of non-native plains minnow (Hybognathus placitus). Hybridization and competition with H. placitus were probable mechanisms of extirpation of H. amarus from the Pecos River. In the lower Rio Grande, Texas, downstream of the Pecos River, extirpation of H. amarus around 1961 was probably related to construction and operation of Amistad Reservoir and introduction of non-native fishes. Local populations of H. amarus (e.g., Rio Grande near Big Bend, Texas) were considered extirpated just after 1960. Hybognathus amarus survives only in New Mexico in 5% of its original range from Cochiti Reservoir downstream to Elephant Butte Reservoir. Conservation measures are necessary as continued habitat and flow modifications, introduction of non-native fishes, and lack of refugia threaten survival of H. amarus.