Giant Salvinia Caddo Lake


Aquatic ecosystems include some of the most imperiled species in the United States and invasive species are the second leading contributor to this problem. Research plays a critical role in guiding effective, science-based monitoring and management of aquatic invasive species. Below is a short description of ongoing and past research projects funded by Texas Parks and Wildlife Department. For more information on the invasive species studied in these projects and other aquatic invasive species in Texas, visit

Ongoing Aquatic Invasive Species Research

Impacts of zebra mussels on native mussels and population dynamics and downstream dispersal of zebra mussels.

Texas State University

Zebra mussels have the potential to negatively affect Texas’ native mussel species, many of which are listed as threatened or endangered species. Zebra mussels attach to their shells and compete with them for food. This study will survey native mussel populations to study zebra mussel fouling of their shells and the health of native mussels and to identify long-term monitoring sites. Laboratory tests will also examine the impacts of zebra mussel die-offs on native species. Additionally, the project will study population dynamics of zebra mussels (for example, settlement and growth rates) in Canyon Lake and their spread in the Guadalupe.

Growth, survival and reproductive success of zebra mussels in Texas lakes

Texas Christian University

Water chemistry plays an important role in the success of zebra mussel invasions. This research project is evaluating how variable water chemistry conditions (for example, calcium concentration) in lakes across the state impact the growth and survival of zebra mussels. Previous studies have shown that calcium is critical for survival and growth of adult zebra mussels. This study will examine whether calcium levels affect zebra mussel egg fertilization, development of larvae, and growth of juveniles and adults.

Combating invasive aquatic plants by manual removal and planting of native aquatic plants

University of Texas at San Antonio, Edwards Aquifer Authority, City of San Marcos, US Fish and Wildlife Service – San Marcos Aquatic Resources Center

Hydrilla is one of the most common invasive aquatic plants in the upper San Marcos River, which is home to endangered Texas wild rice—a submerged aquatic plant—and Fountain Darters. This research is examining whether planting Texas wild rice and other native aquatic plants after hydrilla is manually removed can help to improve the effectiveness of hydrilla management efforts. When the habitat is restored by planting native plants, this study will evaluate whether the native species can suppress or outcompete the invasive hydrilla.

Introduction of non-native fishes in Texas streams

Stephen F. Austin University, Texas A&M University – College Station

Bait-bucket introductions of non-native fishes are widespread in freshwater ecosystems in the US. This may be how two coastal fish species—the Sheepshead Minnow and the Gulf Killifish—were introduced into inland freshwaters outside of their native range in Texas where they may have negative effects on imperiled native fish species. Researchers are conducting bait shop surveys in Texas to learn more about the fish species being sold and whether this is a potential introduction pathway for these two invasive species. Field studies in the Brazos and Red rivers will evaluate the status of populations of these invasive fishes and how they may affect the native aquatic ecosystem. Finally, an ecological model will be developed to map current and possible future introductions of these species across Texas river basins.

View Previously Funded Aquatic Invasive Species Research