Freshwater Mussel Webinar Series

The Freshwater Mussel Conservation Webinar Series aims to provide a vehicle for the freshwater mussel community to share recent advancements in the world of freshwater mussel conservation. This series targets biologists, managers and other members of the conservation community interested in staying up-to-date on the science of freshwater mussel conservation.

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Disclaimer: This webinar series is for educational purposes only. The opinions, ideas or data presented in this webinar series do not represent FWS policy or constitute endorsement by FWS. Some of the materials and images may be protected by copyright or may have been licenses to us by a third party and are restricted in their use. Mention of any product names, companies, Web links, textbooks, or other references does not imply Federal endorsement.



Webinar Descriptions

Advancements in Lab Toxicity Testing with Freshwater Mussels

  • Details: The ASTM International standard for conducting laboratory toxicity tests with freshwater mussels was published in 2006 and needs refinement and additional methods. This webinar will present recently refined methods for chronic water-only and sediment toxicity tests with juvenile mussels and partial life cycle toxicity test starting with gravid female mussels and a newly developed short-term effluent toxicity test with juvenile mussels, as well as the results of using the refined and newly developed methods to evaluate mussel sensitivity to contaminants.

  • Presenters: Dr. Wang (USGS)

  • Recorded: December 1, 2020

  • Duration: 53 Minutes

A Survey-design Framework Based on the Motivating Question(s) to Guide the Choice of Methods and Techniques

  • Details: Effective conservation of freshwater mussels relies on high-quality, management-relevant scientific data and evidence. Data collection and analysis to support freshwater mussel conservation has kept up with the advancement of methods and techniques, such as occupancy modeling, PIT tagging, eDNA sampling, species distribution modeling. Freshwater mussel conservationists now have many options in their survey-design toolbox. But sometimes survey design is approached with the focus on methods application and not by first clarifying the question that is motivating the survey’s need. So, I propose a framework to guide survey design and the choice of methods and techniques based on the fundamental motivating question(s). In this talk, I briefly review the conservation questions that motivate surveys and the core techniques used for freshwater mussel surveys. I hope to stimulate discussion on the current alignment of the core techniques with the motivating questions and the training needs for survey design and implementation.

  • Presenters: Dr. Dave Smith (USGS)

  • Recorded: June 30, 2020

  • Duration: 58 Minutes

CTUIR Mussel Project and Cultural Importance of Mussels

  • Details: The Confederated Tribes of the Umatilla Indian Reservation (CTUIR) manages the only freshwater mussel propagation facility in the western US. CTUIR’s Freshwater Mussel Research and Restoration Project has surveyed, monitored, researched, and protected native freshwater mussels in CTUIR traditional areas since 2002. Research topics include genetics and taxonomy, status and distribution, habitat associations, reproductive biology, artificial propagation and laboratory rearing, and restoration. A recently drafted mussel supplementation plan will direct future mussel restoration efforts in CTUIR managed areas and coordinate restoration work elsewhere in the Columbia River Basin region. The CTUIR Department of Natural Resources manages organisms like freshwater mussels as First Foods, or foods of cultural and ecological value. Though mussels are not regularly harvested or consumed due to low populations, they are managed, conserved, and protected as valued members of the river community. The River Vision, a guiding framework for aquatic restoration work, calls for restoration to be holistic so that a watershed can provide resources well into the future.

  • Presenters: Alexa Maine and Wenix Red Elk (Confederated Tribes of the Umatilla Indian Reservation)

  • Recorded: March 9, 2021

  • Duration: 60 Minutes

Environmental DNA as a Tool for Detection of Western Freshwater Mussels

  • Details: Four freshwater mussel species native to western North America, Gonidea angulata, Margaritifera falcata, Anodonta nuttalliana, and Anodonta oregonensis, have experienced dramatic declines over the last century and are currently threatened in many portions of their ranges. Therefore, improved tools for detecting and monitoring these species are needed. This presentation will provide a brief overview of these species and discuss the role of environmental DNA (eDNA) in basic research and conservation applications for freshwater mussels in western North America, including a species recently petitioned for listing (Gonidea angulata). The presentation will also cover the recent development and implementation of multiplexed, species-specific, quantitative PCR assays, including lab methods and field validation using samples collected from across the western United States.

  • Presenters: Emilie Blevins and Torrey Rodgers(Xerces Society for Invertebrate Conservation), and Torrey Rodgers (Utah State University)

  • Recorded: October 27, 2020

  • Duration: 60 Minutes

Four kinds of mussel declines: a diagnostic pathology approach for identifying causes and solutions

  • Details: Biologists often discuss freshwater mussel declines in general terms, which can conflate unrelated events. The first step in understanding the causes of mussel declines and prescribing a cure is to carefully evaluate the symptoms of declines in a wide range of cases. Doing so reveals at least four distinct types of declines: 1) total elimination of the fauna; 2) overall decline in abundance but little change in species richness or composition; 3) major species loss and faunal shift, usually to dominance by opportunistic life history strategists; and 4) loss of a small, predictable (but ecologically heterogeneous) group of species, while the assemblage otherwise remains intact. Each of these types of declines has a distinctive array of symptoms that suggest very different causal factors and can aid in identifying those factors. I will discuss examples of how this type of diagnostic pathology approach can lead to a better understanding of mussel declines, which is essential for developing effective conservation strategies to address them.

  • Presenters: Dr. Wendell Haag

  • Recorded: October 11, 2020

  • Duration: 58 Minutes

Freshwater Mussel Conservation and Systematics

  • Details: Freshwater bivalves are a diverse radiation of animals restricted to rivers and lakes. They are among the most endangered species on the planet. These animals are the focus of diverse worldwide conservation programs to forestall extinctions. Basic to all conservation is the correct identification of the species being considered. The history of freshwater mussel systematics in North America will be reviewed and its impact on conservation of these imperiled animals.

  • Presenters: Dr. Art Brogan (North Carolina State University)

  • Recorded: September 22, 2020

  • Duration: 56 Minutes

Freshwater Mussel Die-Off Response and One Health Assessment

  • Details: Freshwater mussels are among North America’s most imperiled species. Die-offs are increasingly recognized as population threats, with etiologies frequently undetermined. Minimal health and disease data exists for freshwater mussels. Detailed plans and descriptions of techniques for thorough and rapid diagnostics to guide a targeted die-off response are lacking. This project’s objectives were to develop die-off response protocols in coordination with partners nationwide and establish and compare baseline health parameters for freshwater mollusks in Indiana waterways. Study species included native Fatmucket (Lampsilis siliquoidea) and Plain Pocketbook (Lampsilis cardium) and non-native Asian clam (Corbicula fluminea), all common in Indiana. Methods involved: 1) collection of mollusks (20 per species per site) from three Wildcat Creek drainage sites under assessment for mussel translocation suitability, 2) determination of microbial populations (viral, bacterial, parasitic, and fungal) and antibiotic resistance of bacteria cultured, and 3) assay of hemolymph and tissue samples to determine analyte levels (including metabolomics, glycogen, stable isotopes, contaminants) and histologic tissue evaluation. Using common species, this study allowed for optimization of techniques and protocols for use in diagnostic response to die-offs of potentially endangered species. Preliminary results begin to establish baseline health parameters of multiple species at varied sites which is critical for interpretation of results in the event of a die-off. Analysis of results, compared between species and sites and to water quality parameters, will add to assessment of the suitability of the three sites for translocations, evaluate potential interspecies competition based on dietary composition comparison, identify potential pathogens associated with Asian clam that might threaten native species, and increase understanding of antimicrobial resistance in aquatic environments. Expansion of this pilot study, replicating the protocols and incorporating additional locations, species, and seasons over time, will establish a comprehensive program for understanding challenges to mussel populations while informing management and conservation approaches, including for population restoration. It may generate data to develop risk mitigation strategies for microbes and contaminants that are determined to contribute to freshwater mussel morbidity and mortality.

  • Presenters: Dr. Nancy Boedeker

  • Recorded: August 11, 2020

  • Duration: 54 Minutes

Genomics as an Essential Tool for Freshwater Mussel Conservation

  • Details: Freshwater mussels are among the most imperiled groups of organisms on the planet. Yet, compared to other groups like mammals and fish, they are woefully understudied. In order for conservation plans to be successful, managers need data on a range of topics, including toxicology, systematics and taxonomy, landscape genetics, and genetic management of propagated populations. Here, I will provide an overview of ongoing mussel research at the USFWS Southeast Conservation Genetics Lab, with an emphasis on genomic tools for enhancing management outcomes. I will briefly give a history of mussel genetics work, but I will focus on emerging technologies and exciting research directions. New genomic tools being used by USFWS provide high resolution data for answering questions about genetic diversity across a species’ range, patterns of gene flow, and how species are genetically responding to changing environments. Genomic data can also be used to assess how current best-practice captive propagation protocols influence genetic diversity of captively reared and reintroduced populations. During this talk, I will use the federally threatened Louisiana Pearlshell (Margaritifera hembeli) as a model to explain how genomic data are increasing our understanding of a critically imperiled freshwater mussel. Recent work from my lab has revealed low genomic diversity in Louisiana Pearlshell but a surprising amount of gene flow among remaining populations. We also demonstrated that Louisiana Pearlshell females mate with multiple males in the wild, which has implications for best-practice propagation protocols. Finally, I will talk about new technologies being used by USFWS that are enabling assembly of cost-effective reference genomes for non-model organisms like freshwater mussels, and I will discuss how such data can be used to examine selection at the genomic level. Conservationists face many challenges to ensuring the survival of freshwater mussels, but new genomic technologies have great potential for improving management outcomes.

  • Presenters: Dr. Nathan Whelan

  • Recorded: July 28, 2020

  • Duration: 62 Minutes

Infectious Threats to Freshwater Mussels: How Worried Should We Be?

  • Details: Freshwater mussels around the world are declining at unprecedented rates, but the causes have remained elusive. This talk describes research into the role of infectious disease in mass die-offs of freshwater mussels. Using epidemiological study designs and metagenomic methods for pathogen discovery, we are working to identify infectious agents associated with mussel die-offs in the USA and beyond. Recently, we characterized the “virome” of pheasantshell mussels in the Clinch River, Tennessee and Virginia, and identified a novel densovirus (family Parvoviridae) strongly linked to disease. We are replicating these methods in other locations, and we are conducting field and laboratory studies to determine the mechanisms by which putative pathogens may be killing mussels. Our ultimate goal is to develop preventions and treatments to safeguard mussel health and thus to inform conservation and management.

  • Presenters: Dr. Tony Goldberg and Jordan Richard

  • Recorded: January 12, 2021

  • Duration: 60 Minutes

Tagging and Monitoring Freshwater Mussels - Insights Gained During 3 Conservation Projects

  • Details: Mark-recapture studies are commonly used by conservation biologists to gain insight on ecological questions. However, some organisms are easier to mark and recapture than others. Although native freshwater mussels are relatively sessile, their burrowing behavior and the variable environments they occupy can make them difficult to tag and recapture. Until recently, studies of movement and survival of mussels in natural systems were constrained due to the difficulty of relocating individual mussels. Passive integrated transponder (PIT) tags have allowed scientists to tag and recapture mussels with considerably higher recapture rates than using visual searches alone. We herein offer insights to tagging and recapturing mussels using different PIT tag arrays, across a variety of habitats, and across the country. Our collaborative presentation will showcase four case studies illustrating different tagging techniques, applications to relocation projects, and applications for estimating survival and growth. Collectively, we hope to share our experiences with tagging and monitoring mussels to biologists and managers who wish to address a variety of science and management questions.

  • Presenters: Brian Watson, Jeremy Tiemann and Dr. Teresa Newton

  • Recorded: September 8, 2020

  • Duration: 57 Minutes

The Current State of Freshwater Mussel Propagation: New Advancements and Tricks of the Trade

  • Details: The science of freshwater mussel propagation has made great strides in recent years. New advancements in in vitro metamorphosis, culture systems, and feeding protocols have greatly increased our ability to culture large numbers of juveniles of a wide array of species for restoration, recovery, and laboratory research. This webinar will provide a behind the scenes look at some of the latest advancements as well as some insights on what works and what doesn’t work to help avoid repeating mistakes and reinventing the propagation wheel. The presentation will include insights and tips from four mussel propagation biologists from four different propagation facilities that work with different species and deal with different propagation issues.

  • Presenters: Rachel Mair (USFWS), Rachael Hoch (USFWS) and Chris Eads (North Carolina State University)

  • Recorded: March 5, 2021

  • Duration: 64 Minutes

The Functional Ecology of Freshwater Mussels

  • Details: Freshwater mussel beds are hot spots of biological activity. Mussels provide or improve habitat for other organisms through their shells and by modifying sediment and near-bed flows through their burrowing and filtering. Filter-feeding mussels remove living and detrital organic matter from the water column, metabolize the labile fractions, excrete dissolved nutrients back to the water, and deposit organic nutrients to the sediment as feces and pseudofeces. In green food webs, nutrient excretion by mussels enhances benthic primary production and influences algal species composition, which in turn supports higher in-stream production of macroinvertebrates, and is exported to the terrestrial environment by emerging aquatic insects. Mussel excretion also enhances production of emergent macrophytes, which are consumed by terrestrial herbivores. In brown food webs, mussel biodeposits are an important food source for invertebrate and fish detritivores. Nutrients retained, translocated and transformed by mussels can alleviate nutrient limitation, decrease nutrient loss downstream, change stoichiometric nutrient ratios, and meet a significant proportion of local nutrient demand. Mussel effects on biofiltration and nutrient dynamics are context dependent and vary with environmental conditions, mussel abundance, and mussel species traits. The functions performed by mussels in rivers provide ecosystem services to humans including regulating services (biofiltration), supporting services (nutrient recycling and storage, structural habitat, substrate and food web modification, use as environmental monitors), and provisioning and cultural services (food, tools and jewelry, spiritual enhancement). Mussel-provided ecosystem services are declining because of large declines in mussel abundance. Mussel propagation could be used to restore populations of common mussel species and their ecosystem services.

  • Presenters: Dr. Caryn Vaughn

  • Recorded: August 25, 2020

  • Duration: 52 Minutes

The New Freshwater Mussel Silo: Design, Construction and Conservation Application

  • Details: Mussel silos are portable passive flow devices for caging juvenile mussels in streams. Silos allow periodic monitoring of survival and growth, and are used to test pollution effects, site suitability for population restoration, and for ecological studies. This webinar will present an updated design and detailed instructions for construction and use of mussel silos.

  • Presenters: Chris Barnhart

  • Recorded: July 14, 2020

  • Duration: 68 Minutes

Using Population Viability and Demographic Analyses to Develop Quantitative Criteria to Guide Mussel Restoration

  • Details: Federal recovery plans for freshwater mussels provide criteria to down-list and de-list species. However, these criteria are rarely quantitative enough to assess population performance or provide specific guidance on what constitutes a viable population. As biologists attempt to restore mussels throughout the country, development of quantitative metrics to assess population performance and viability will be critical to the success of these restoration and recovery efforts. We often have more questions than answers when we start thinking about the long-term viability of mussel populations and sometimes this uncertainty hinders progress toward metric and criteria development. For example, how will we know when a population is large enough to ensure long-term viability? What stocking strategies should we use to maximize viability? When can we stop stocking and redirect resources to a different population or priority species? Can population viability analysis (PVA) help develop these criteria? I will use demographic data from the federally endangered oyster mussel (Epioblasma capsaeformis) collected over a four-decade period in the Clinch River, Tennessee to demonstrate how key demographic metrics such as density-abundance targets, recruitment rates, age-structure, and population ceilings (K) can be used to assess population performance and population viability for this species. I advocate for simple but nonetheless quantitative criteria for E. capsaeformis and other mussel species, believing that adapting and updating imperfect criteria is better than having no criteria at all. Ultimately, we should not let a desire for “perfect criteria” to be the enemy of “good criteria”.

  • Presenters: Dr. Jess Jones

  • Recorded: October 13, 2020

  • Duration: 74 Minutes

What are Freshwater Mussels Worth?

  • Details: The advent of the ecosystem services framework has raised the question of what freshwater mussels really are worth, and how we might best use this information in environmental decision-making. I will briefly discuss why it might be useful to try to assign values to freshwater mussels, review the different kinds of values that freshwater mussels provide (including direct-use values, indirect-use values, existence values, option values, bequest values and replacement values), describe progress towards providing quantitative estimates of those values, and discuss problems with these valuation approaches. Despite uncertainty about the precise value of freshwater mussels, it is clear that they can have very substantial value to humans, which should be taken into account in environmental decision-making.

  • Presenters: Dr. Dave Strayer

  • Recorded: June 16, 2020

  • Duration: 59 Minutes