Assessing and refining copper-based treatment to suppress zebra mussel populations

The goal of this project is to provide decision-making support for the use of copper in lake management for controlling zebra mussel veligers with a copper-based molluscicide in select, high value habitats while minimizing non-target impacts. Researchers will determine minimal effective treatment concentrations of copper to suppress zebra mussel recruitment and evaluate beneficial and adverse impacts to the ecosystem.

Progress Update, February 2024:

In July 2022, researchers applied a small amount of a copper-based substance called EarthTec QZ™ in Maxwell Bay, Lake Minnetonka. They used a part of North Arm Bay as a comparison to see how effective the treatment was. Their findings showed that three months after the treatment, there was less settlement of zebra mussels, but there was also a significant decrease in the population of tiny animals called zooplankton.

Now, the research team is continuing their project to see how the treatment affects zebra mussel numbers and the native creatures living in the lake for a year after the treatment. In the first six months of this phase, they've made a plan for their study and got permission to take samples from specific spots in the two bays they're studying. They've set up devices to collect zebra mussels and other small creatures at ten locations in these bays. They've already done three out of seven planned sampling sessions in May and June. During these sessions, they measured how much copper was in the water and sediment, looked at what kinds of zooplankton and phytoplankton were present, and counted how many zebra mussel larvae (called veligers) there were.

All this data is really important for comparing how things were before and after the treatment in both bays and seeing how it affects zebra mussels and other creatures living there.

Alongside this work, they're also wrapping up another project in St. Albans Bay and getting ready for a workshop with people interested in the lake. With extra funding, they're also looking into how zebra mussels react to the copper treatment at different times of the year. They've done three out of six tests in May and June to see how much copper it takes to kill the mussels. In these tests, they're also looking at how healthy the mussels are, whether they're ready to reproduce, how much copper is in their bodies, and how certain enzymes in their bodies react to the metal. All this info will help figure out the best time to use the treatment to control the mussels.


Dahlberg, A.D., Waller, D.L., Hammond, D. et al. Open water dreissenid mussel control projects: lessons learned from a retrospective analysis. Sci Rep 13, 10410 (2023).

Hernández Elizárraga, V. H., Ballantyne, S., O’Brien, L. G., Americo, J. A., Suhr, S. T., Senut, M.-C., Minerich, B., Merkes, C. M., Edwards, T. M., Klymus, K., Richter, C. A., Waller, D. L., Passamaneck, Y. J., Rebelo, M. F., & Gohl, D. M. (2023). Toward invasive mussel genetic biocontrol: Approaches, challenges, and perspectives. iScience, 26(10).


Prairie Sportsman, aired April 2023


Project Information

Project manager: Diane Waller (Formerly led by Jim Luoma)

Project timeline: 2018-2024

Organismal Group: Invertebrates

Funding: $121,609

Funded by: Environment and Natural Resources Trust Fund as recommended by the Legislative-Citizen Commission on Minnesota Resources with additional support from the State of Minnesota, the Fletcher Family Foundation, Bay Lake Improvement Association, Pelican Lakes Association of Crow Wing County, USGS, and Hennepin County.


Project update handout (PDF, 2021)