LAUSR

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.