Conservation Partners connecting working lands conservation from the Gulf of Mexico to the High Plains with the vision of a sustainable landscape of natural resources resilient to the threats and stressors associated with our changing world.

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    Guadalupe Bass S Llano River

    Guadalupe bass in the South Llano River
    Photo courtesy of Preston Bean

Understanding how river flow affects Guadalupe Bass and other species

Formal Title: Guadalupe Bass flow-ecology relationships; with emphasis on the impact of flow on recruitment

Research Focus: Focal Species – Guadalupe Bass

Conservation & Management Challenges:

Flow alteration -- from new and existing water supply projects, increased urbanization, and drought conditions -- is a pervasive threat to aquatic wildlife throughout the Gulf Coast Prairie region.  One species susceptible to this threat is Guadalupe Bass, an economically and ecologically important black bass species endemic to Texas.  The area encompassing their range is projected to experience some of the highest population growth in Texas, placing increased demands on the aquifers and watersheds of this region.  A previous GCP LCC Instream Flow project conducted by the Southeast Aquatic Resources Partnership (SARP) produced hypotheses about instream flow requirements of native aquatic species that need to be tested.  This project will clarify how changes in flow are likely to affect Guadalupe Bass and will make recommendations for conservation of this priority species.  Knowledge of how to manage sustainable Guadalupe Bass populations will benefit invertebrates, such as Quadrula mussels, and other fish species with similar instream flow requirements.

Research Overview:

Understanding the interplay of recruitment, growth, and mortality, and how environmental conditions and ecological interactions influence fish populations is critical to predicting and modeling species responses to both environmental disturbances and management strategies.  A combination of historical and contemporary data will be used to assess the role of discharge (from dams and other hydrological alterations) on Guadalupe Bass year class strength through reproduction and recruitment.  These data will help to assess three hypotheses explaining how instream flow affects (a) growth and recruitment, (b) habitat quality and availability, and (c) nest success during spawning season of Guadalupe and other black bass species.  Final products will include:


View a recorded webinar presenting an update of the Guadalupe Bass project in December 2016


This 36-month project was initiated in May 2015 and is scheduled for completion in August 2018.  The Gulf Coast Prairie Landscape Conservation Cooperative is funding this project.

Access Guadalupe Bass project reports on ScienceBase


Principal Investigator:  Dr. Tim Grabowski U.S. Geological Survey, Texas Cooperative Fish and Wildlife Resarch Unit, Texas Tech University P.O. Box 42120 Lubbock, TX 79409-2120

Landscape Conservation Cooperative Point-of-Contact: Bill Bartush, Gulf Coast Prairie Landscape Conservation Cooperative, National Wetlands Research Center, 700 Cajundome Boulevard, Lafayette, LA 70506  

Photo credit: Clinton & Charles Roberts, Flickr Creative Commons

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