Zebra mussels, pictured in a DNR exhibition, overcome native mussels and can block pipes — they’ve been found growing inside boat motors. (Photo by T.W. Budig)
The Department of Natural Resources has confirmed zebra mussels in northwestern Minnesota’s Lake Ida (Becker and Otter Tail counties), but alert DNR staff may have prevented a potentially broader infestation. Five zebra mussels were also confirmed in Lake Sylvia in Stearns County. On Oct. 6, DNR fisheries staff spotted 10 to 15 dead zebra mussels on a trailer at the Detroit Lakes north public water access. The trailer belonged to a business that takes boating equipment in and out of lakes. It had been out of the water several weeks and had last been used on Lake Ida. DNR fisheries staff alerted the DNR aquatic invasive species staff and contacted a conservation officer, who issued the business a warning. The business then decontaminated the trailer. Immediately following the discovery on the trailer, a DNR aquatic invasive species crew conducted an inspection. “We searched the area around the north Detroit Lakes public access and did not find any zebra mussels,” said Mark Ranweiler, DNR assistant invasive species specialist. “Because the trailer had been on Lake Ida, we immediately conducted a search on that lake.” The crew conducted a day search of docks and lifts on Lake Ida on Oct. 13 and found 40 juvenile and adult zebra mussels distributed across four locations. The mussels ranged in size from one-eighth to three-quarters of an inch. “Although low in numbers, zebra mussels are present and distributed around Lake Ida, not localized in one area,” Ranweiler said. “Because zebra mussel discoveries were made in various locations in the lake, treatment does not appear to be an option.”
Lake Ida, part of the Otter Tail River watershed, will be added to the infested waters list.
The presence of zebra mussels on the trailer is an important reminder to lakeshore property owners. Anyone who purchases water-related equipment must carefully inspect the equipment for all aquatic invasive species before putting it in any body of water.
A small lake in Stearns County will also be listed as infested after five zebra mussels were found. A homeowner on 85-acre Lake Sylvia, northwest of St. Cloud, took their pontoon boat to a shop for service Oct. 11. An employee at the shop contacted a DNR conservation officer after finding three zebra mussels on the boat. DNR staff searched most of the docks and lifts on the small lake and found two zebra mussels about one-third mile from where the pontoon had been docked. The DNR will evaluate next steps for Lake Sylvia, and is considering whether any downstream or upstream connected waters will be added to the infested waters list. This time of year, when cabins are being closed up, is an especially important time to check boats, docks, lifts and other equipment for zebra mussels. By law, docks and lifts must also dry for at least 21 days before putting them into another body of water, whether they are coming from an infested lake or not. A photographic guide showing where and how to check docks and lifts for zebra mussels is available at www.dnr.state.mn.us/invasives/shoreland_owners.html.
Before leaving a lake, Minnesota’s aquatic invasive species laws require boaters and anglers to:
–Clean aquatic plants and animals from watercraft.
–Drain all water by removing drain plugs and keeping plugs out while transporting watercraft.