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

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

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

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

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

The environmental fate, persistence, and point-source discharge of traditional molluscicidal compounds led to the development of an alternative biomolluscicide, Zequanox. Previous studies evaluated the efficacy and non-target animal safety of Zequanox in laboratory, mesocosm, and field enclosure studies. One study indicated sensitivity of salmonid species and lake sturgeon (Acipenser fulvescens Rafinesque 1817) following exposure to Zequanox, however, the exposures were not conducted in a manner consistent with the product label. This laboratory study evaluated sublethal and lethal impacts of Zequanox on lake sturgeon and lake trout (Salvelinus namaycush Walbaum in Artedi, 1792) following exposures that were conducted consistent with a Zequanox open-water label application. Fish were exposed to 50 and 100 mg Zequanox active ingredient/L for 8 h and then held for an additional 33-d for post-exposure observation. No acute mortality was observed in either species, however, significant latent mortality (46.2%) was observed in lake trout that were exposed to 100 mg of Zequanox active ingredient/L for 8 h. At the termination of the 33d holding period, biologically minimal, yet statistically significant, differences were observed in the terminal weight of surviving lake sturgeon (range 20.17 to 21.49 g) and biologically, as well as, statistically significant differences were observed in the terminal weight of surviving lake trout (range 6.19 to 9.55 g). Histological evaluation of lake trout gastrointestinal tracts suggest that a different mode of action is responsible for the Zequanox exposure-related impacts to lake trout than the mode of action that induces zebra and quagga mussel mortality. Further research is required to determine if Zequanox sensitivity is limited to lake trout or if all salmonid species are vulnerable to exposure and to determine if native fish will avoid Zequanox exposure.

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 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.

Dispersal, establishment, and spread of aquatic invasive species such as the zebra mussel (Dreissena polymorpha) can be influenced by riverine velocities and volumetric flows in invaded lake-stream ecosystems. Zebra mussels, which have a planktonic larval form (veliger), disperse rapidly downstream from a source population. Concentrations, dispersal, and body conditions of zebra mussel veligers were studied under different volumetric flow, or discharge, conditions in a coupled lake-stream ecosystem in northern Texas, USA. Veliger densities in lotic environments were strongly related to population dynamics in upstream lentic source populations. A strong exponential decrease in veliger density was observed through a 28-km downstream study reach. Increased water releases from the source reservoir increased veliger flux and dispersal potential, concomitantly increasing veliger flux and decreasing transit time. However, passage through release gates in the dam and increased turbulence in the river during high-discharge events could negatively affect body condition of veligers, and veliger body condition generally decreased from the source population to the farthest downstream site and was lower for veligers during periods of high discharge. Thus increased discharge appears to reduce the proportion of viable veligers because of increased turbulence-induced mortality. Colonization of distant downstream reservoirs can occur if discharge and propagule pressure are sufficient or if interim habitats are suitable for establishment of in-stream populations.

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.