Residual water study looks at zebra mussel veliger transport
Research on the risks posed by microscopic zebra mussel larvae spreading through the residual water left in watercraft after draining is entering its second field season.
MAISRC graduate student Adam Doll is collecting water samples from various compartments in watercraft, including live wells, ballast tanks, and motors, which he will analyze for the presence of zebra mussel larvae (veligers). These samples are being collected from Lake Minnetonka and Gull Lake, both of which have established zebra mussel populations. Over 200 samples were collected in 2016, with researchers hoping to gather 200 more this year.
In partnership with the DNR’s Watercraft Inspection Program, researchers are also analyzing data on the presence and location of zebra mussels on different types of boats such as fishing, wakeboard, and pontoon boats.
Partners have also been extremely important in getting water samples from the more difficult-to-access internal compartments of inboard and inboard/outboard motors. Tonka Bay Marina, a marina on Lake Minnetonka, stepped up to help Doll by providing access to watercraft with these components.
Along with examining residual water samples for the presence of veligers, researchers will evaluate how long veligers can live in various water temperatures inside live wells through lab experiments.
“Recreational boats are widely suspected to be vectors for overland transport of zebra mussels, but we really don’t know much about the risks of residual water,” said Doll. “This research is working to find answers to questions like where in the boat veligers may be getting, and whether they’re alive.”
Results from this study may inform state inspection and decontamination protocols, as well as help boat manufacturers understand potential redesign options that could reduce the risk of spread.
“Minnesota has the highest per capita watercraft ownership in the country,” added Doll. “That’s why it’s so important that we figure out the risks and look what we can do to manage those risks.”
This project is funded by the Brunswick Foundation, the Brunswick Freshwater Boat Group, and Tonka Bay Marina, with in-kind support provided by the Minnesota DNR. Learn more about MAISRC research on zebra mussels on our website.