Zebra mussels (Dreissena polymorpha) have continued their spread within inland lakes and rivers in North America despite diligent containment and decontamination efforts by natural resource agencies and other stakeholders. Identification of newly infested waterways with early detection surveillance programs allows for rapid response zebra mussel eradication treatments in some situations. Previous eradication treatments have been conducted during times of variable water temperatures and temperature has been shown to influence the efficacy of molluscicides. Natural resource managers would benefit from knowledge regarding the impacts of water temperature and exposure duration on toxicity of molluscicides to zebra mussels. In particular, temperature specific data are needed to inform the selection of an effective molluscicide and the proper dose that will induce 100% zebra mussel mortality. We evaluated the influences of temperature and exposure duration on the toxicity of two EPA-registered (EarthTec QZ and Zequanox) and two nonregistered (niclosamide and potassium chloride) molluscicides to zebra mussels at water temperatures of 7, 12, 17, and 22 °C. Our results indicate that treatment options for the eradication of zebra mussels in waters ≤ 12 °C include 336 h or longer treatments with EarthTec QZ and KCl and treatments with niclosamide ≥ 24 h in duration. In waters ≥ 17 °C, multiple toxicant and exposure duration combinations would be effective for zebra mussel eradication treatments. However, site specific variables should be considered prior to treatment including: the extent of the infestation, water chemistry, aquatic vegetation, substrate, and the presence of nontarget organisms. The use of on-site or in situ zebra mussel bioassays would also be a useful tool for the evaluation of treatment efficacy. The dataset includes: Water Quality, Chemical Concentrations, Mortality, and Zebra Mussel Condition Data

Zebra mussels (Dreissena polymorpha Pallas 1771) are a tenacious aquatic invasive species in the United States and new infestations can rapidly expand into dense colonies. Zebra mussels were first reported in Marion Lake (Dakota County, Minnesota) in September 2017 and surveys indicated the infestation was likely isolated near the public boat access. A 2.4-hectare area, containing the known zebra mussel infestation, was enclosed and treated for nine days with EarthTec QZ®, a copper-based molluscicide, in an attempt to eradicate the zebra mussels. We conducted an on-site bioassay to confirm treatment efficacy. The bioassay was conducted in mobile assay trailer that received a continuous flow of treated lake water and zebra mussels test animals that were collected from White Bear Lake (Ramsey County, MN). Zebra mussel mortality in the treated bioassay tanks achieved 99 percent mortality (95-percent Confidence Interval: 98 – 100 percent) and a predictive model indicates in-lake mortality as low as 85 percent may have occurred; therefore, our results indicate that the Marion Lake treatment may not have induced complete zebra mussel mortality. Post-treatment assessments and surveys are recommended to further verify treatment success and monitor lake conditions in regards to zebra mussel infestation.

Zebra mussels (Dreissena polymorpha Pallas 1771) are a tenacious aquatic invasive species in the United States and new infestations can rapidly expand into dense colonies. Zebra mussels were first reported in Marion Lake (Dakota County, Minnesota) in September 2017 and surveys indicated the infestation was likely isolated near the public boat access. A 2.4-hectare area, containing the known zebra mussel infestation, was enclosed and treated for nine days with EarthTec QZ®, a copper-based molluscicide, in an attempt to eradicate the zebra mussels. We conducted an on-site bioassay to confirm treatment efficacy. The bioassay was conducted in mobile assay trailer that received a continuous flow of treated lake water and zebra mussels test animals that were collected from White Bear Lake (Ramsey County, MN). Zebra mussel mortality in the treated bioassay tanks achieved 99 percent mortality (95-percent Confidence Interval: 98 – 100 percent) and a predictive model indicates in-lake mortality as low as 85 percent may have occurred; therefore, our results indicate that the Marion Lake treatment may not have induced complete zebra mussel mortality. Post-treatment assessments and surveys are recommended to further verify treatment success and monitor lake conditions in regards to zebra mussel infestation.

Zebra mussels are representative of nonindigenous aquatic species (NAS) with devastating economic, recreational, and environmental impacts that are already under watch as a problematic species across the U.S. and in Texas. Targeting dispersal pathways is likely the most efficient means of controlling their spread further west. The movement of recreational watercraft is one of the main vectors for the spread of zebra mussels and other NAS among lakes. Thus, we created a risk assessment to guide monitoring efforts to detect and report new sightings of zebra mussels and other NAS. Lake risk scores were based on the potential establishment and spread of zebra mussels. Lake establishment risk was determined by applying a habitat suitability index (HSI) of water physicochemical parameters compiled from preexisting sources and supplemental field collection (Child Item 1: "Water physicochemical parameters of twenty Texas and New Mexico lakes 2022-2023"). The risk of spreading zebra mussels from a lake was determined by centrality measures of network analysis to identify lakes acting as hubs (degree score), stepping stones (betweenness score), and cutpoints. We applied network analysis at three different maximum roadway distances based on the 95th , 75th , and 50th percentiles of boater movement. The combination of HSI and centrality scores (Child Item 2: "Habitat suitability scores, network scores, and infestation status for 225 lakes in Texas and New Mexico") were used to identify potential high risk lakes.

Zebra mussels are representative of nonindigenous aquatic species (NAS) with devastating economic, recreational, and environmental impacts that are already under watch as a problematic species across the U.S. and in Texas. Targeting dispersal pathways is likely the most efficient means of controlling their spread further west. The movement of recreational watercraft is one of the main vectors for the spread of zebra mussels and other NAS among lakes. Thus, we created a risk assessment to guide monitoring efforts to detect and report new sightings of zebra mussels and other NAS. Lake risk scores were based on the potential establishment and spread of zebra mussels. Lake establishment risk was determined by applying a habitat suitability index (HSI) of water physicochemical parameters compiled from preexisting sources and supplemental field collection (Child Item 1: "Water physicochemical parameters of twenty Texas and New Mexico lakes 2022-2023"). The risk of spreading zebra mussels from a lake was determined by centrality measures of network analysis to identify lakes acting as hubs (degree score), stepping stones (betweenness score), and cutpoints. We applied network analysis at three different maximum roadway distances based on the 95th , 75th , and 50th percentiles of boater movement. The combination of HSI and centrality scores (Child Item 2: "Habitat suitability scores, network scores, and infestation status for 225 lakes in Texas and New Mexico") were used to identify potential high risk lakes.

Data is a spreadsheet of the number of copies of Zebra Mussel DNA detected and the number of positive detections for Zebra Mussel DNA from water samples collected over 6 different substrates, at 4 depths in 2 lakes. The ash-free dry weight of the mussels at each of the sites is also included for each sampling location.

Data is a spreadsheet of the number of copies of Zebra Mussel DNA detected and the number of positive detections for Zebra Mussel DNA from water samples collected over 6 different substrates, at 4 depths in 2 lakes. The ash-free dry weight of the mussels at each of the sites is also included for each sampling location.

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.

We applied Zequanox using a custom-engineered, boat mounted application system to replicated 0.30 Hectare plots within a small inland lake. The objectives of these applications were to determine if uncontained, open-water Zequanox applications could effectively control zebra mussel populations and protect native unionid mussel populations within zebra mussel infested systems. The datasets included are as follows: Exposure Water Chemistry Hardness and Alkalinity Native Mussel Sonde Water Chemistry Zebra Mussel Density Zebra Mussel Length Zebra Mussel Mortality Zequanox Concentration ShapeFiles: PLOTS, UNIONID, ZEQUANOX CONCENTRATION, ZM_DENSITY, ZM_MORTALITY