Observations on Habitat Use of Age-0 Rio Grande Blue Sucker (Cycleptus sp. cf. elongatus)

Abstract

During April 2018, we collected 23 age-0 (33–55 mm total length) Rio Grande Blue Sucker (Cycleptus sp. cf. elongatus) from 3 locations in the Rio Grande near the confluence with the Rio Conchos where the species is rarely reported. Age-0 Rio Grande Blue Suckers occurred in habitats ranging from 6 to 81 cm deep, with current velocities ranging from 0 to 1.03 m/s over silt, sand, gravel, cobble, and bedrock substrates. There was limited evidence for greater detection in slower-velocity habitats with bedrock, silt, and sand substrates, but the habitats we sampled were not unique from habitats sampled in a previous year-round study reporting only a single individual. We conclude that our sampling occurred shortly after successful recruitment, and that age-0 Rio Grande Blue Suckers use a wide variety of habitats.