Movement and Habitat Use of Triploid Grass Carp in a Colorado Irrigation Canal

Abstract

Abstract Movement and habitat use of 14 triploid grass carp Ctenopharyngodon idella in the South Platte Supply Canal, Colorado, were monitored with radiotelemetry. Radio transmitters were surgically implanted into abdominal cavities of study fish and were retained for as long as 17 months. Daily movement and habitat use of acclimated (resident in canal for at least 7 d) and nonacclimated (resident in canal for less than 2 d) grass carp were observed by radio-tracking each fish at hourly intervals for at least 24 h. In total, movements of nine acclimated and five nonacclimated grass carp were observed on three and two 24-h sampling occasions, respectively. At night, acclimated grass carp repeatedly used portions of the canal that were less than 2 m downstream of tiled groundwater inputs, and movement was at a daily minimum. During daytime, acclimated grass carp dispersed from nighttime locations and preferred portions of the canal where rooted aquatic vegetation was abundant. Daytime movement and habitat u...