All hands on deck for aquatic invasive species control

A Ramsey County crew uses the decontamination unit to clean a kayak.

News about aquatic invasive species (AIS) is becoming commonplace, andh newly discovered infestations are regularly making headlines. The Minnesota Department of Natural Resources has been combatting invasive plants, fish and invertebrates for decades across the state. But these days, the war on AIS is also being waged by local government entities and lake associations.

The DNR’s watercraft inspection program has become one of the most familiar means of preventing the spread of AIS. It began in 1992 and currently has around 92 inspectors working in the field, educating the public and watching for signs of “aquatic hitchhikers.” It also operates dozens of traveling decontamination units, where boats can be cleaned thoroughly.

According to information provided by the DNR, the state partners with local government units (LGUs) to provide many more inspections and decontaminations. As a result of this cooperation and support, there were around 850 inspectors in the field in 2020, who conducted more than 600,000 inspections around the state. There were also 54 active decontamination units, operated by 20 different LGUs.

One such LGU is Ramsey County, which conducts education and watercraft inspections, and has one decontamination unit that travels to different public access sites. The self-contained unit holds up to 500 gallons of water, which are heated to AIS-killing temperatures (but safe for boats and equipment) before being applied to watercraft. The water is then captured and cycled through the machine repeatedly to avoid contaminating nearby waterbodies.

Justin Townsend, Ramsey County environmental specialist, says the county is also engaged in AIS early detection. One method is using eDNA technology to screen for zebra mussels in lakes. Water samples are sent to labs for analysis in the hope that DNA evidence of zebra mussels would be detected before the mussels themselves ever turn up.  

In Washington County, the Washington Conservation District (WCD) performs AIS education, watercraft inspections and what it calls “early detection and rapid response.” The early detection component consists of frequent checks at all public access points in Washington County, as well as whole-lake surveys of Big Marine, Big Carnelian, and Square Lakes. From the WCD website: “These surveys and visual inspections are an important tool for identifying AIS, because not every boat entering and leaving the water can be inspected.” If a new case of AIS turns up, WCD works with the DNR to “create a rapid response plan to inform the public and evaluate the extent of the infestation.”

Another component of the battle on AIS in Washington County is a grant program that funds projects designed to prevent AIS introductions or limit their spread. According to Washington County Planner II Maureen Hoffman, the county receives funds from the DNR’s aquatic invasive species prevention aid program, which it then distributes among successful applicants. “Typically, most applicants are lake associations.”

Awardees in 2019 included one watershed district, the St. Croix River Association and seven lake associations. According to the 2019 report, the Comfort Lake Forest Lake Watershed District performed watercraft inspections on Forest and Bone lakes, as well as control of flowering rush. Work performed by lake associations—including on Clear, Big Marine and Forest lakes—appears to have been largely directed at control of Eurasian watermilfoil.

Kevin Ousdigian, president of the Turtle Lake Association of Shoreview (TLAS), lives on the lake and has been very involved with AIS control efforts there. He reports that TLAS has spent more than $100,000 on invasive species management over the years, most of that work targeting Eurasian watermilfoil. TLAS has also worked hard in recent years to eradicate another invasive plant that was new to the lake (and Minnesota): non-native phragmites.

Ousdigian says that around four years ago, TLAS shifted more of its focus onto prevention of AIS. After battling weed infestations, it became clear that keeping invasive species out to begin with could be the better strategy. “What can we do to prevent or delay the introduction of invasives?”

In answering that question, they have been spending around $6,000 a year in order to have more frequent boat inspections at the access. Also, in June 2020 TLAS partnered with Ramsey County to install a CD3 cleaning station, the first and only one in the county. TLAS put up 75% of the funds (almost $24,000); the county covered the rest. It has a vacuum, compressed air, cleaning tools and the ability to track and report its usage.

Ousdigian said TLAS was also considering the installation of a video monitoring system at the access that would have issued audible reminders to boaters to clean boats before launching them, but Ramsey County would not allow it. They were hoping it would not only remind, but also deter boaters from launching irresponsibly.

Like other lake associations in the area, TLAS is serious about AIS control and remains vigilant. Ousdigian says, “We’re working on management and prevention.”


Roy Heilman is a contributing writer for Press Publications. He can be reached at or 651-407-1200.



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