Predicting the Vulnerability of Texas Reservoirs to Zebra Mussel Invasion

The Zebra Mussel continues to expand its range across North America despite varied efforts at containment and apparent physicochemical barriers. Early research had suggested that high water temperatures would prevent their spread and establishment in Texas. However new records in the reservoirs of the Trinity and Brazos River Basins in northern Texas reflect the continued south and westward expansion of Zebra Mussel. Significant economic and ecological costs are expected as Texas relies heavily on reservoirs for municipal water supply. Furthermore, recreational freshwater fisheries  in Texas reservoirs are significant economic drivers to local economies. Our objectives were to evaluate the potential impacts of Zebra Mussels on Texas freshwater fisheries under a “do nothing” and a “maximum containment effort” scenario using Generic Algorithm for Rule-set Production (GARP) modelling. We incorporated water chemistry, published physiological tolerances, and boater movement data to predict the spread and establishment of Zebra Mussels throughout the Trinity River Basin and adjacent watersheds.  Our results will allow resource managers to prioritize the most immediately threatened reservoirs and focus limited resources to prevent colonization and spread.