Use of carbon dioxide in zebra mussel (Dreissena polymorpha) control and safety to a native freshwater mussel (Fatmucket, Lampsilis siliquoidea)

Control technology for dreissenid mussels (Dreissena polymorpha and D. bugensis) currently relies heavily on chemical molluscicides that can be both costly and ecologically harmful. There is a need for more environmentally neutral tools to manage dreissenid mussels, particularly in cooler water. Carbon dioxide (CO₂) has been shown to be lethal to several species of invasive bivalves, including zebra mussels and Asian clams (Corbicula fluminea). We evaluated the effectiveness of unpressurized infusion of CO₂ for 24 to 96 h (100 000–300 000 µatm PCO₂) at a water temperature of 12 °C on mortality, byssal thread formation, and attachment of zebra mussels. The safety of elevated CO₂ to a nontarget native freshwater mussel (Fatmucket, Lampsilis siliquoidea) was also determined. Elevated PCO₂ exposure induced narcotization and reduced attachment of zebra mussels within 24 h. Mortality increased with exposure duration and PCO₂. An estimated LT50 (lethal time to produce 50% mortality) for fixed PCO₂ ranged from 24 h at 275 000 µatm to ~ 96 h at 100 000 µatm. Exposure of zebra mussels to CO₂ for 96 h caused 80–100% mortality at all treatment levels. Fatmucket juveniles survived all PCO₂ treatments but burial and byssal thread production were adversely affected during exposure. Our results demonstrate that CO₂ is a viable option for management of zebra mussels in cool water and may have less adverse effect for native lampsiline mussels than current-use molluscicides.