Project background
Despite zebra mussels being wildly successful at reproducing and spreading in Minnesota lakes, they are incredibly difficult to maintain and propagate in a lab setting. This presents a challenge for researchers because many studies require multiple generations of zebra mussels to assess the long term impacts of control options, particularly genetic methods. MAISRC researchers are learning how to sustain zebra mussels in a lab setting in order to learn more about them.
In phase II of this project, MAISRC researchers advanced efforts to rear invasive zebra mussels in a controlled setting by focusing on improved nutrition, better husbandry practices, reducing competitors, and finding collection sites closer to the Twin Cities. Weekly tank cleanings and feeding a specific algae species, Chlamydomonas reinhardtii, led to healthier mussels with increased weight and successful spawning. Refining water purification and washing methods reduced competitors and fouling, enabling larvae to develop to a critical stage, known as D-stage veligers, for the first time. Additionally, researchers identified Cedar Lake as a new collection site with favorable conditions, which will enhance efficiency and support propagation efforts.
Project update (June 2026)
Rearing zebra mussels in a laboratory is really difficult because scientists must replicate the environmental conditions, dietary components, and seasonal cues that support each stage of the mussel's complex life cycle. Zebra mussels reared in the laboratory last summer and overwinter showed improved survival and growth compared to previous years due to aquarium water quality improvements and refined feeding strategies. Researchers also found that particle size and palatability play an important role to support optimal growth and development of adult and larval mussels.
Researchers are refining zebra mussel husbandry techniques that could support aquatic invasive species management tools, including genetic biocontrol approaches. Next, the team will investigate how feeding frequency, additional diets, and light conditions influence zebra mussel growth, survival, and reproduction in captivity.
Phase I
Title: Rearing Zebra Mussels in the MAISRC Containment Lab
Project manager: Nick Phelps, MAISRC
Funded by: MAISRC and the Environment and Natural Resources Trust Fund as recommended by the Legislative-Citizen Commission on Minnesota Resources
Project timeline: Jan. 2021 - Dec. 2024
Findings: Researchers made important progress toward completing the zebra mussel life cycle in the laboratory by developing reliable methods for growing algae, maintaining adult mussels, inducing spawning, and rearing larvae. The team successfully cultured the algae needed to feed adult mussels and refined spawning techniques, including a new method for collecting fresh sperm that helped improve fertilization efforts. While spawning success increased later in the summer, especially for mussels collected from Big Wolf Lake, relatively few females produced eggs and overall egg production remained low, limiting the number of larvae that could be raised. Despite these challenges, improved water quality and feeding methods allowed some larvae to survive and develop to eight days of age, providing valuable insights into zebra mussel reproduction and helping researchers identify the next steps needed to establish a fully self-sustaining laboratory population.