Movements and Habitat Use of Guadalupe Bass Using Radio Telemetry in the Lower Colorado River, Texas

Guadalupe Bass Micropterus treculii are endemic to Texas and can be found throughout the Colorado River Basin. Guadalupe Bass are commonly associated with smaller tributaries but a Guadalupe Bass fishery can also be found on the mainstem lower Colorado River. The gradient of disturbance across the Colorado River Basin imposes differing pressures on Guadalupe Bass populations.  Documenting movement and differences in habitat association between tributary and mainstem sites will facilitate the assessment of a variety of anthropogenic influences on populations. The objective of our study is to determine if the habitat associations and occupancy patterns of Guadalupe Bass in the lower Colorado River downstream of Austin are similar to those described for counterparts in smaller tributaries upstream. Twenty-seven Guadalupe Bass were collected and surgically implanted with radio transmitters. Individuals have been tracked and associated with recorded habitat data. Preliminary data show large movements occurring following high flow events. Overall, Guadalupe Bass in the lower Colorado River are moving greater distances than previously described for individuals tagged in tributaries of the upper Colorado River. Ongoing research on movement patterns and habitat associations will allow for assessment of how Guadalupe Bass in the lower Colorado River differ from those in upstream tributaries.