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 to develop more environmentally neutral control tools to manage dreissenid mussels, particularly in cooler water. Carbon dioxide has been shown to be lethal to several species of invasive bivalves, including zebra mussels and Asian clams (Corbicula fluminea). We evaluated the effects of various treatment regimes [i.e., exposure duration and pCO2 (partial pressure of carbon dioxide)] on mortality, byssal thread formation and attachment, and narcotization behavior. The effects of elevated carbon dioxide on nontarget native freshwater mussel Lampsilis siliquoidea were also measured. Results of trials conducted at 12°C indicated that carbon dioxide exposure induced narcotization behavior and reduced attachment of zebra mussels within 24 h. An extended exposure duration (96 h) produced 80-100% mortality of zebra mussels, and was safe to juvenile L. siliquoidea mussels. The results indicate that carbon dioxide could be used in an integrated pest management program for dreissenid mussels

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 to develop more environmentally neutral control tools to manage dreissenid mussels, particularly in cooler water. Previously, carbon dioxide (CO2) showed selective toxicity for Zebra mussels, relative to unionids, when applied in cool water (12 °C). Carp-Carbon Dioxide (carbon dioxide, CO2) is registered as a pesticide by the U.S. Environmental Protection Agency (EPA) for deterrence of Asian carp and to control aquatic nuisance species when applied under ice (USEPA 2019). The current registration would allow the use of CO2 to kill Zebra mussels in water bodies during periods of ice cover, but first efficacious treatment regimes in cold water need to be determined. We compared toxicity endpoints (lethal concentrations, time to lethality) and behavioral responses of Zebra mussels (gaping, attachment) and juveniles (burial) of two unionid species (Plain pocketbook, Lampsilis cardium) and Fragile papershell (Leptodea fragilis) to CO2 across a temperature range to determine treatment scenarios that had the greatest efficacy to invasive mussels and safety margin to native mussels. We found CO2 treatment regimens at all three temperatures that were efficacious to Zebra mussels and caused minimal mortality of unionid. At 5 °C, Plain pocketbook survived 96 h exposure to the highest PCO2 treatment (139 atm). At 20 °C, the 96 h LC10 for Plain pocketbook (173 atm PCO2, 95% confidence interval CL 147 – 198 atm) was significantly higher than the LC99 for Zebra mussels (118 atm PCO2, CL 109 – 127 atm). Lethal time to 99% mortality (LT99) of Zebra mussels in PCO2 ~ 110 – 120 atm ranged from 100 h at 20 °C to 300 h at 5 °C. Mean survival of unionids exceeded 85% in LT99 CO2 treatments at all temperatures. Seasonal behaviors of native mussels are also considered to assess the potential risk of a CO2 treatment to unionids. Short-term infusion of 100 to 200 atm PCO2 at a range of water temperatures could reduce biofouling by Zebra mussels.

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 to develop more environmentally neutral control tools to manage dreissenid mussels, particularly in cooler water. Previously, carbon dioxide (CO2) showed selective toxicity for Zebra mussels, relative to unionids, when applied in cool water (12 °C). Carp-Carbon Dioxide (carbon dioxide, CO2) is registered as a pesticide by the U.S. Environmental Protection Agency (EPA) for deterrence of Asian carp and to control aquatic nuisance species when applied under ice (USEPA 2019). The current registration would allow the use of CO2 to kill Zebra mussels in water bodies during periods of ice cover, but first efficacious treatment regimes in cold water need to be determined. We compared toxicity endpoints (lethal concentrations, time to lethality) and behavioral responses of Zebra mussels (gaping, attachment) and juveniles (burial) of two unionid species (Plain pocketbook, Lampsilis cardium) and Fragile papershell (Leptodea fragilis) to CO2 across a temperature range to determine treatment scenarios that had the greatest efficacy to invasive mussels and safety margin to native mussels. We found CO2 treatment regimens at all three temperatures that were efficacious to Zebra mussels and caused minimal mortality of unionid. At 5 °C, Plain pocketbook survived 96 h exposure to the highest PCO2 treatment (139 atm). At 20 °C, the 96 h LC10 for Plain pocketbook (173 atm PCO2, 95% confidence interval CL 147 – 198 atm) was significantly higher than the LC99 for Zebra mussels (118 atm PCO2, CL 109 – 127 atm). Lethal time to 99% mortality (LT99) of Zebra mussels in PCO2 ~ 110 – 120 atm ranged from 100 h at 20 °C to 300 h at 5 °C. Mean survival of unionids exceeded 85% in LT99 CO2 treatments at all temperatures. Seasonal behaviors of native mussels are also considered to assess the potential risk of a CO2 treatment to unionids. Short-term infusion of 100 to 200 atm PCO2 at a range of water temperatures could reduce biofouling by Zebra mussels.

Carbon dioxide has shown promise as a tool to control movements of invasive Asian carps. We evaluated lethal and sublethal responses of juvenile fat mucket (Lampsilis siliquoidea) mussels to carbon dioxide concentrations (43–269 mg/L, mean concentration) that are effective for deterring carp movement. The 28-d LC50 value (lethal concentration to 50% of the mussels) was 87.0 mg/L (95% confidence interval, CI 78.4–95.9) and at 16-d post-exposure was 76.0 mg/L (95% CI 62.9–90.3). A proportional hazards regression model predicted that juveniles could not survive CO2 concentrations 160 mg/L for more than 2 weeks or 100 mg/L CO2 for more than 30 days. Mean daily shell growth was significantly lower for mussels that survived carbon dioxide treatments; however, growth during the post-exposure period did not differ among treatments, indicating recovery of the mussels. Carbon dioxide also caused shell pitting and erosion of the periostracum in mussels. Behavioral effects of carbon dioxide included movement of mussels to the substrate surface and narcotization in the highest concentrations. Mussels in 110 mg/L, mean CO2 had the most movements, particularly in the first 3 days of exposure. If carbon dioxide is infused continuously as a fish deterrent, concentrations below 76 mg/L are recommended to prevent juvenile mussel mortality and shell damage. Mussels may survive and recover from brief exposure to higher concentrations.

Carbon dioxide has shown promise as a tool to control movements of invasive Asian carps. We evaluated lethal and sublethal responses of juvenile fat mucket (Lampsilis siliquoidea) mussels to carbon dioxide concentrations (43–269 mg/L, mean concentration) that are effective for deterring carp movement. The 28-d LC50 value (lethal concentration to 50% of the mussels) was 87.0 mg/L (95% confidence interval, CI 78.4–95.9) and at 16-d post-exposure was 76.0 mg/L (95% CI 62.9–90.3). A proportional hazards regression model predicted that juveniles could not survive CO2 concentrations 160 mg/L for more than 2 weeks or 100 mg/L CO2 for more than 30 days. Mean daily shell growth was significantly lower for mussels that survived carbon dioxide treatments; however, growth during the post-exposure period did not differ among treatments, indicating recovery of the mussels. Carbon dioxide also caused shell pitting and erosion of the periostracum in mussels. Behavioral effects of carbon dioxide included movement of mussels to the substrate surface and narcotization in the highest concentrations. Mussels in 110 mg/L, mean CO2 had the most movements, particularly in the first 3 days of exposure. If carbon dioxide is infused continuously as a fish deterrent, concentrations below 76 mg/L are recommended to prevent juvenile mussel mortality and shell damage. Mussels may survive and recover from brief exposure to higher concentrations.

Data were collected during experiments to determine the effects of water chemistry on carbon dioxide toxicity to zebra mussels (Dreissena polymorpha). Water chemistry parameters were collected for the water used in the study. Data were collected to model the relationship of carbon dioxide and pH in various water chemistries. Measurements were made to describe the animals used in the study.

Data were collected during experiments to determine the effects of water chemistry on carbon dioxide toxicity to zebra mussels (Dreissena polymorpha). Water chemistry parameters were collected for the water used in the study. Data were collected to model the relationship of carbon dioxide and pH in various water chemistries. Measurements were made to describe the animals used in the study.

We evaluated the efficacy of carbon dioxide (CO2) for preventing settlement of the biofouling quagga mussel (Dreissena bugensis) in raw water systems. Trials were conducted in a mobile laboratory located at the US Bureau of Reclamation, Davis Dam Hydropower Facility, and supplied with raw water from the Colorado River. Incoming water was split between five chambers where CO2 was dissolved into the water at five concentrations. Chamber outflows were mixed with raw water which was infested with quagga larvae (veligers) and then delivered to test tanks containing settlement plates. We conducted two 18-d trials; trial 1 tested continuous infusion with (target concentrations) 30, 45, 60, 75, and 100 mg/L dCO2. Trial 2 evaluated intermittent infusion schedules: 24 h on/off with 50, 75, and 100 mg/L dCO2 and 24 h once/week with 100 mg/L dCO2. At the end of each trial, we counted the number of settled quagga on plates in each treatment and modeled predicted settlement, relative to untreated water, by CO2 treatment.

We evaluated the efficacy of carbon dioxide (CO2) for preventing settlement of the biofouling quagga mussel (Dreissena bugensis) in raw water systems. Trials were conducted in a mobile laboratory located at the US Bureau of Reclamation, Davis Dam Hydropower Facility, and supplied with raw water from the Colorado River. Incoming water was split between five chambers where CO2 was dissolved into the water at five concentrations. Chamber outflows were mixed with raw water which was infested with quagga larvae (veligers) and then delivered to test tanks containing settlement plates. We conducted two 18-d trials; trial 1 tested continuous infusion with (target concentrations) 30, 45, 60, 75, and 100 mg/L dCO2. Trial 2 evaluated intermittent infusion schedules: 24 h on/off with 50, 75, and 100 mg/L dCO2 and 24 h once/week with 100 mg/L dCO2. At the end of each trial, we counted the number of settled quagga on plates in each treatment and modeled predicted settlement, relative to untreated water, by CO2 treatment.

Locks and dams are possible management points to block the spread of invasive Asian carps in the United States. Infusion of carbon dioxide (CO2) into water is one deterrent strategy being considered at navigational structures to reduce upstream fish passage that would not directly interfere with lock and dam operations. The goal of this study was to determine lethal concentrations of CO2 to non-target species. Bluegill (Lepomis macrochirus) and Fathead minnows (Pimephales promelas) were exposed to CO2 continuously for 12 hours using a diluter system. Trials were performed on both species at target water temperatures of 5, 15, and 25°C. See related manuscript for additional details on experimental methods.