Presentations include:

More than we bargained for: Zebra mussels transported amongst European native freshwater snails by James Dickey with Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany

The international pet trade is a major driver of non-native species spread, including species both sold in the trade, and organisms incidentally transported alongside. Here, we document the discovery of invasive zebra mussels, Dreissena polymorpha, in Germany, transported alongside a commonly traded garden pond snail and European native, Viviparus viviparus, ordered from a German pet website. We highlight that the trade poses yet another way in which zebra mussels and other invasive species can expand their invaded range into novel ecosystems. We call for stricter biosecurity enforcement towards sellers, and encourage raising awareness amongst customers to inhibit the further spread of invasive species through the pet trade.

Assessing Dreissena spread in Lake Superior through traditional and eDNA surveys by Courtney Larson with the US EPA Office of Research and Development, Great Lakes Toxicology and Ecology Division, Duluth, MN

Lake Superior is generally considered to be inhospitable to invasive Dreissena mussels, yet there is a large colony in the Saint Louis River estuary and smaller colonies in the Apostle Islands. Through traditional and eDNA surveys in 2017, 2019, and 2022, we found multiple sources of evidence of a propagule “conveyor belt” for Dreissena in Lake Superior and conclude veligers are functioning as a propagule, using coastal currents to spread from the point of invasion, thereby traversing coastal habitat previously reported as inhospitable to distant habitats suitable for colonization. These currents and environmental conditions can be variable, and increasingly so with climate change; therefore, early detection monitoring for Dreissena is important for continued conservation of Lake Superior biodiversity and habitat.

Chemical drivers of Dreissenid habitat: Moving beyond calcium and temperature by Daniel Sandborn with the University of Minnesota Duluth

Dreissenid mussels have proven to be very capable invaders of diverse freshwater ecosystems since their arrival in North America nearly 35 years ago, yet their distribution remains limited in certain regions (e.g. Lake Superior). We apply two novel tools to the task of understanding Dreissenid dispersion:

1)Measurement of calcium carbonate saturation state as a habitat predictor combining chemical and physical measurements into a thermodynamically-rigorous description of Dreissenid shell solubility, and

2)Computer models tracking veliger transport across a gradient of calcium carbonate saturation state.

Combining these oceanographic tools and applying them to a large lake ecosystem yields insights into mussel invasion, survival, and the future of Dreisseina in North America.