Midwest Fish & Wildlife Conference 2019

AUTHORS: Kishore Gopalakrishnan, Donna Kashian, Anna Boegehold, Nick Johnson – Wayne State University

ABSTRACT: Dreissenid mussels are successful invaders in a wide variety of freshwater environments. As biofoulers, they create serious economic and recreational problems. In addition, these rapid filter feeders alter their invaded ecosystem by disrupting the entire food web. Their rapid colonization rate and environmental resilience make them difficult to control. Many management options have been explored for combating the spread of dreissenid mussels, but an effective management strategy is elusive.  In an effort to identify a novel management tool, we investigated the impacts of cyanobacteria, commonly associated with Harmful Algal Blooms (HABs), on reproduction in dreissenid mussels. Mussel populations may be regulated by HABs through several reproductive mechanisms including spawning and fertilization. Specifically we tested the impacts of several bloom forming cyanobacterial species on quagga mussel reproduction through a series of bioassays examining quagga mussels’ spawning, fertilization and sperm motility. Mussel were induced to spawn using serotonin, then the effect of five cyanobacterial species spawning and sperm motility was examined. Sperm motility was determined by recording the movement of sperm from five males per treatment at 400X, tracking velocity and distance travelled. Fertilization success was determined through assays combining quagga mussels’ egg and sperm in individual vials containing cyanobacteria species cultures (n=5), and enumerating zygote formation marked by cellular cleavage. Some cyanobacteria species inhibited reproductive endpoints; spawning was inhibited by Microcystis wesenbergii and M. ichthyoblabe, sperm motility was reduced by Aphanizomenon flos-aquae and two strains of M.aeruginosa and fertilization ratio decreased with exposure to five unique species of cyanobacteria including two strains of M. aeruginosa. These results show the HABs may negatively impact dreissenid populations. Determining the class of compounds and understanding the mechanism by which the cyanobacteria disrupts reproduction may inspire new dreissenid control tactics.

AUTHORS: David Hammond, Ph.D., Earth Science Laboratories, Inc.;Gavin Ferris, M.S., Solitude Lake Management, Inc.

ABSTRACT: In 2017 Earth Science Labs, Inc. designed and supervised a treatment protocol to eradicate invasive quagga mussels from the lake at Billmeyer Quarry in Pennsylvania.  The treatment consisted of 3 separate applications of a liquid formulation of ionic copper called EarthTec QZ, delivered over a period of 37 days.  Mussel mortality was determined through use of caged adult mussels that were suspended at different locations and depths throughout the lake.  Mussels began to die within 3 days of the initiation of treatment, particularly in the top 20 feet of the water body.  The death of the last caged mussel was confirmed 40 days after the initiation of treatment, in a cage that had been placed at a depth of 30 feet below the surface.  Both biological and physicochemical data collected during the treatment period revealed that there was a pronounced thermocline at 25-35 foot depth.  Such stratification is historically typical for this lake.  The layer of water in the thermocline resisted mixing, which explains why mussels located above and below the thermocline were eradicated quickly, yet those within the thermocline required targeted treatment techniques and 40 days to succumb to 100% mortality.  Microscopic analysis of plankton tows and visual inspection of the shoreline after partial pump-down of the quarry in early November indicated that all veligers and adults were successfully exterminated.  Analysis of eDNA taken in December 2017 also suggests the eradication was complete.  The cumulative sum of copper applied throughout the entire course of treatment totaled 0.44 mg/L – noteworthy because it is less than half the concentration EPA allows (1.0 mg/L) in a single algaecide treatment.  The authors are cautiously optimistic that this is the first recorded instance of eradicating quagga mussels from an entire lake.

AUTHORS: Todd Severson, James Luoma, Jeremy Wise, Matthew Barbour – US Geological Survey

ABSTRACT: Because zebra mussels (Dreissena polymorpha) continue to spread through inland lakes and rivers of North America somewhat undeterred, the need to develop tools to control their populations has become a major research effort.  Developing data regarding the impacts of water temperature and exposure duration on the toxicity of chemical molluscicides to zebra mussels will assist resource managers to select a treatment regimen with the greatest potential for successful eradication. We evaluated the toxicity of two EPA-registered (EarthTec QZ and Zequanox) and two nonregistered (potassium chloride and niclosamide) zebra mussels toxicants over a range of water temperatures and exposure durations. We evaluated each toxicant in replicated laboratory studies conducted at 7, 12, 17, and 22°C using exposure durations ranging from 8 hours to 14 days. The minimum lethal concentration of toxicant(s) and the exposure duration required to achieve complete zebra mussel mortality at each test temperature will be presented.

AUTHORS: Joel G. Putnam, Diane Waller, Justine Nelson– US Geological Survey Upper Midwest Environmental Sciences Center; Tammy J. Clark, Viterbo University

ABSTRACT: The search for new chemical controls for aquatic invasive species (AIS) that are efficacious and selective is needed to expand the arsenal of AIS control tools for resource managers. Chemical control options for dreissenid mussels (Dreissena polymorpha and D. bugensis) currently rely heavily on molluscicides that can be costly and/or harmful to nontarget species. The Environmental Protection Agency ECOTOX Knowledgebase was used to gather toxicity data for over 400 taxa covering five kingdoms and 7700 chemicals. Our search used structural activity relationships (SARs) to correlate chemical information with biological activity and predict new chemicals that are effective against dreissenid mussels. A database of chemical descriptors, such as molecular weight, solubility, and polar surface area, was created and published to link the chemical structure/information with species-specific toxicity. Toxicity trials have been initiated using a category of chemicals with high selective toxicity towards dreissenid mussels. Chemicals that produced significant mortality of dreissenid mussels were also tested on nontarget native freshwater mussels to determine selectivity. The results of toxicity trial will be combined with chemical characteristics (e.g., solubility) to identify toxicants that may be suitable for incorporation into a microparticle that is ingested by dreissenid mussels.

AUTHORS: Seth Donrovich, Marrone Bio Innovations

ABSTRACT: Zequanox molluscicide, a biological control for invasive dreissenid mussels, has been available for commercial use in enclosed and open water systems for approximately six years. During this time, the product has undergone development and been strategized for a variety of applications and markets. The product was recently trialed in Florida on Mytilopsis leucophaeata, with enough activity to warrant further experimentation. A biobox demonstration trial has been conducted at a hydroelectric generating station in Spain, the first trial of Zequanox in the EU. Furthermore, recently developments in fermentation has led to reduced product costs, and treatment strategies continue to be optimized with dose and hold and low dose maintenance programs being implemented. MBI looks forward to continuing collaboration on product development for use in enclosed water systems, as well as looking to optimize the product for open water applications, including development of a slow release granule or encapsulated formulation.   

AUTHORS: Matthew T. Barbour, James A. Luoma, Todd J. Severson, Jeremy K. Wise – US Geological Survey

ABSTRACT: Zequanox® is an EPA-registered molluscicide for controlling populations of dreissenid mussels (zebra and quagga mussels). Zequanox® has demonstrated selective toxicity to dreissenid mussels. However, recent research indicates Zequanox can impact body condition and even cause mortality in non-target species.  We assessed the avoidance behavior of two species each of cold-, cool-, and warm-water fish (lake trout, brook trout, lake sturgeon, yellow perch, and fathead minnow) to Zequanox® at the maximum concentration allowed by the product label (100 mg A.I./L).  Naïve, juvenile fish were individually (n = 30) observed in a two-current choice tank through which treated and untreated water flowed simultaneously on either side.  Each individual fish was observed during a control period (20 min) with no treatment and two treatment periods (20 min each) between which the treated side was alternated to eliminate bias.  Positional data was collected and tabulated in real time with EthoVision® XT software.  Zequanox® concentrations and water quality (pH, dissolved oxygen, temperature, and specific conductance) were monitored during each trial.  Results from this research will help inform resource managers of the likelihood of fish to avoid Zequanox® treated areas, thereby assisting in the establishment of treatment-related risk assessments.

AUTHORS: Erika Jensen, Great Lakes Commission; Sandra Morrison, U.S. Geological Survey; Ceci Weibert, Great Lakes Commission

ABSTRACT: The Invasive Mussel Collaborative is working to advance scientifically sound technology for invasive mussel control to produce measurable ecological and economic benefits. The Collaborative provides a framework for communication and coordination and is identifying the needs and objectives of resource managers; prioritizing the supporting science, implementing communication strategies; and aligning science and management goals into a common agenda for invasive mussel control. The founding members of the collaborative are the U.S. Geological Survey, Great Lakes Commission, National Oceanic and Atmospheric Administration and the Great Lakes Fishery Commission. The Great Lakes Commission provides coordination and neutral backbone support for the collaborative. A broad membership base of states, provinces, tribal and other entities and a well-organized communication network facilitates the exchange of information between scientists, managers, and stakeholders. Strong connections with other regions outside the Great Lakes are in place to provide opportunities to share lessons learned. The Collaborative maintains a robust communication network to facilitate information-sharing on priority issues related to management and control of dreissenid mussels. The Collaborative also develops products and tools to support and advance management activities and will soon finalize a regional strategy to advance zebra and quagga mussel management for the Great Lakes region. This presentation will provide an update on these efforts.

AUTHORS: Sherri Pucherelli, Bureau of Reclamation

ABSTRACT: The Bureau of Reclamation oversees water resource management in the western United States and is responsible for the operation of diversion, delivery, storage and hydropower facilities. The first detection of invasive dreissenid mussels in the western United States was in the Lower Colorado River in 2007. Hydropower facilities along the Colorado River have experienced operational impacts related to the presence of the mussels, including unplanned outages, overheating of critical systems, and increased maintenance. Reclamation is actively involved in the development and examination of a variety of control methods to reduce the impacts of invasive mussels in Reclamation managed waters and hydropower facilities. Development of passive and environmentally responsible methods for mussel settlement prevention on critical structures at hydropower facilities has been the focus of the research. Methods examined for settlement prevention in generator cooling systems include ultra-violet light, turbulence, laser-pulsed pressure, and carbon dioxide. The durability and effectiveness of anti-fouling and foul-release coatings have been extensively examined for use on equipment such as trash racks and fish screens. Centrifugal separation and self-cleaning strainers and filtration are being examined for shell debris mitigation. Reclamation is also currently involved in several research projects designed for mussel eradication in open water including biocontrol agent identification, genetic control methods, and potash. Additionally, Reclamation is planning to peruse the winning solution resulting from the recent crowdsourcing prize challenge designed to elicit theoretical solutions for the eradication of invasive mussels in open water.

AUTHORS: Dan Molloy, Molloy & Associates, LLC

ABSTRACT: Dreissena mussels pose a significant challenge to infrastructures. One key element contributing to this challenge is the lack of a practical method for large-scale control of populations once they become established throughout a water body. As a result, facilities drawing water from such water bodies are subjected to constant reinfestation. Although concerns exist about environmental impacts of molluscicides, it is the prohibitive total project cost of open-water control programs that currently eliminates them as a mitigation option. Total project cost includes not only the molluscicide and its application throughout the entire water body, but also a myriad of other expenses often required in the overall control program, such as fund raising, administration, regulatory approval, post-treatment mussel mortality monitoring, report writing, etc. The research project reported herein offers a potential solution to this seemingly intractable problem of prohibitively high control program expense. The key to the low cost of this proposed control approach is that it does not require treatment of the entire water body. In contrast to traditional control programs: 1) only a minuscule portion of the infested water body’s volume would be treated (“seeded”) with the control agent; and 2) the control agent would subsequently amplify itself and self-spread throughout the water body. There is only one type of control agent capable of doing that – a live one, a biological control agent. This presentation describes the research conducted in the first year of a multi-year project to find such a control agent. The project is based in Eurasia and specifically designed to find a hypervirulent (i.e., extremely lethal), highly-specific dreissenid parasite that one day (following years of comprehensive environmental safety studies) would be introduced into North American water bodies where it will leave a trail of dead dreissenids in the path of its spread.

AUTHORS: Kevin R. Keretz; Richard T. Kraus, Joseph Schmitt – US Geological Survey

ABSTRACT: Ecological and societal impacts of dreissenid mussels (Dreissena spp.) on Great Lakes ecosystems are well documented, and a better understanding of the mechanisms that cause variation in mussel abundance is needed.  An outstanding question is how much mussel biomass is consumed by predation. To date, attention has mainly been focused on invasive Round Goby (genus species) predation of mussels.  We note that the biomass of native mussel consumers, such as Freshwater Drum (Aplodinotus grunniens), may exceed Round Goby biomass by an order of magnitude in some areas.  Thus, the role of predation on mussel population dynamics may be greater than is currently assumed.  A significant difficulty for investigating mussel consumption by native predators is that mussels in stomachs are often a macerated mix of crushed shell and flesh. This prevents counting and measurement of individual prey items as is often performed in diet studies.  Here, we develop an analysis to convert the crushed shell and flesh mixture found in diets of Freshwater Drum to a simple dry weight of mussel flesh.  We then estimate daily ration as a first step in understanding the impact of Freshwater Drum on mussel populations in Lake Erie.  Our results support evaluation of proposed mussel control methods by improving our knowledge of ecological mechanisms that influence mussel abundance.  

AUTHORS: Lewis Steven Beckham, Barnacle-Blocker, LLC

ABSTRACT: The efficacy in situ of Mussel Stopper®, a brand name for a water insoluble, non-toxic, patented (10,053,584B1), US EPA labeled (89825-1) repellent for Dreissena mussels that can be applied underwater is being measured in a multi-location, multi-year randomized testing program. Testing apparatus consists of a PVC frame with six treatment sets of black ABS plastic coupons attached with cable ties. The ABS plastic coupons have one smooth side and one textured side. Treatments are untreated, component wax only and Mussel Stopper® applied according to labeled directions.  The test lattices are suspended in the water column in locations picked for high incidence of Dreissena mussels. The tests are periodically lifted out of the water and visually rated for percent coverage by the mussels. Since each test has two sides, a total of twelve replications per location are evaluated. After two years of testing, Mussel Stopper® treated coupons averaged 0.60% covered. Component wax only treated coupons averaged 17.7% covered and untreated coupons have averaged 84.8% coverage. Standard deviation is 38.4%. Testing continues, but so far Mussel Stopper® performance is significantly better than the checks.KEY WORDS: Mussel Stopper, Dreissena mussels, applied underwater, US EPA labeled, non-toxic, water insoluble