Collaborative Invasive Fish Research

Bighead Carp

Several species of Asian carp have been introduced to North America, and have been especially problematic in the Mississippi River drainage. At least one species (Bighead Carp) has been found in Texas. Because young Asian carp look very similar to native shads, our regulations restrict transfer of nongame fish in some parts of East Texas to help keep the invasive carp from spreading through bait bucket transfers. TPWD partnered with Texas Tech University (TTU) to conduct a project using traditional electrofishing surveys and cutting-edge "eDNA" analysis to study where invasive Asian carp are present and where they might be able to thrive in Texas. The results of this study suggest that invasive Asian carp are present but rare in Texas waters and do not appear to have spread beyond the areas where preventive regulations are in effect. However, continued efforts to increase awareness of their presence will be important for preventing accidental transfer of these fish into the upstream reservoirs (Texoma, Toledo Bend, Wright Patman, Lake O’ The Pines) where they could potentially establish reproducing populations and become more of a problem.

Asian Carp identification poster

Tilapia Data Gap and Risk Analyses

Tilapia (multiple species) have been widely introduced across Texas, and may have little impact in most areas. However, they are becoming increasingly common in sensitive headwaters creeks and rivers, where they could threaten imperiled fishes by competing for resources and degrading water quality with their nesting activity. In response to this concern, TPWD partnered with TTU to review available science on tilapia and species that may be affected, and to identify critical knowledge gaps to help guide efforts to manage and regulate these prohibited fishes. Tilapia have become more widespread than originally thought possible. This study showed that we need to take a closer look at their reproduction in Texas and the role played by thermal refuges such as springs in enabling them to survive winters. Twenty-eight imperiled fish species were found to be susceptible to negative impacts from tilapia. Effective, science-based management approaches that balance conservation and economic interests are essential to reduce the likelihood that invasive tilapia may contribute to the decline and ultimate federal listing of those native fishes.

Armored Catfish Biology

Armored catfish, commonly sold in aquarium stores as “algae eaters” or “plecos,” have also been widely introduced into Texas waters, where they burrow into river banks, destabilizing them and degrading water quality. TPWD collaborated with SWCA Environmental Consultants and Texas A&M University to complete a study of armored catfish reproduction and growth in Landa Lake (Comal River). The armored catfish species found in Landa Lake has many traits that make them extremely successful invaders, including parental care of their young. The results of this research suggest that identifying nesting sites, developing sampling techniques that target small armored catfish, and timing removal efforts to take place in winter or early spring months may help to increase the effectiveness of control efforts. Science-based management strategies are essential for reducing impacts and promoting long-term persistence of native fish and wildlife in rivers plagued by armored catfish.

Learn More

Good Fish, Bad Fish - Texas Parks & Wildlife, November 2016