Guadalupe Bass Habitat Use Patterns at a Landscape Scale

Guadalupe Bass Habitat Use Patterns at a Landscape Scale

Jillian R. Groeschel¹ and Timothy B. Grabowski²

¹Texas Cooperative Fish and Wildlife Research Unit, Texas Tech University, Lubbock, Texas 79409-2120, (806)742-0841, jillian.groeschel@ttu.edu

²U.S Geological Survey, Texas Cooperative Fish and Wildlife Research Unit, Texas Tech University, Lubbock, Texas 79409-2120, (806)742-2851

The Guadalupe bass Micropterus treculii is endemic to the streams and rivers of the Edwards Plateau and lower Colorado River in central Texas. Its dependence on undisturbed pool and run habitats with sufficient flow and cover, render it sensitive to habitat alteration. It is currently state-listed as a species of greatest conservation need due to decreased stream flow, habitat degradation, and, especially, genetic introgression with introduced smallmouth bass Micropterus dolomieui. Restoration efforts are underway to restore Guadalupe bass populations, however detailed habitat use data to evaluate their effectiveness is lacking. The objective of our study was to determine Guadalupe bass habitat associations relative to availability, degradation, fragmentation, and time of year and day as well as build the knowledge base necessary to develop a guide for restoring ecosystem composition and functionality in the Llano River watershed and throughout the Edwards Plateau. We used PIT-tag telemetry to assess habitat use, site fidelity, and habitat specific growth rates of juvenile Guadalupe bass. Transect snorkel surveys were completed to identify adult and subadult Guadalupe bass habitat associations. Our results demonstrate how Guadalupe bass use habitat at a landscape scale, how that habitat might overlap with other black bass species, and how restoration efforts directed at the species could be made more effective. Further application may demonstrate the use of the Guadalupe bass population trajectories and habitat occupation rates as an indicator of stream health in Edwards Plateau streams or as a predictor of changes in stream condition.