Repatriation of Guadalupe Bass in the Blanco River, Texas: A Case Study in the Opportunistic Use of Drought as a Fisheries Management Tool
Stephan Magnelia, Gordon Linam, Ryan McGillicuddy, Ken Saunders, Melissa Parker, Timothy Birdsong, Dijar Lutz-Carillo, Jánaye Williamson, Rachael L. Ranft, and Timothy Bonner
Abstract.—Repatriation of Guadalupe Bass Micropterus treculii was undertaken in the Blanco River, Texas, after extirpation due to hybridization with non-native, introduced Smallmouth Bass Micropterus dolomieu. In summer 2011, much of the river was reduced to a series of disconnected, enduring pools due to severe drought. Electrofishing and seines were used to remove Smallmouth Bass from fifty-two enduring pools in a 24-km reach of the river upstream of a natural fish passage barrier. After the removal effort was completed, stockings of non-introgressed, hatchery-produced Guadalupe Bass fingerlings ( n = 316,016) were initiated in spring 2012 when river flows returned. Successful recruitment of wild, naturally-produced Guadalupe Bass was documented in fall 2014 and 2015. In the reach where Smallmouth Bass were removed, only Guadalupe Bass were detected, despite a historic flood event in spring 2015, which provided an opportunity for upstream movement of Smallmouth Bass and Guadalupe Bass x Smallmouth Bass hybrids past the barrier.