LIVING ON THE EDGE: POPULATION DYNAMICS OF ZEBRA MUSSELS IN A TEXAS RESERVOIR
Canyon Lake, a reservoir in central Texas, was invaded by zebra mussels in 2016 and represents the most southwestern edge of this species current distribution in North America. The purpose of this study was to examine the distribution, population dynamics and potential limiting factors of zebra mussels in this newly invaded lake with a combination of seasonal dive surveys, monthly field monitoring, and lab experiments between 2017 and 2019. Scuba surveys along transects in different parts of the lake found zebra mussel densities tended to increase with depth and decrease with distance away from the dam. Scuba surveys also detected a massive, lake-wide, die off of adult individuals occurring up to approximately 12m depth in late summer of 2018. Temperature was a major driver of both lake veliger densities and juvenile settlement rates and preliminary results from ongoing field and lab experiments suggest that temperature was also a major driver of survival of settled individuals, whereas dissolved oxygen was not. Continued monitoring of population dynamics of different life stages will help to better understand potential driving factors and future studies should examine the impact of massive die-offs on ecosystem processes.
Josi Robertson (Primary Presenter/Author), Texas State University, firstname.lastname@example.org;
Astrid Schwalb (Co-Presenter/Co-Author), Texas State University, email@example.com;