Water sampling efforts have detected the presence of two microscopic, larval zebra mussels, also called veligers, in Lake Winnibigoshish located in Cass and Itasca counties, the Minnesota Department of Natural Resources (DNR) said.
As part of a statewide program examining aquatic systems in large lakes, sets of water samples were collected by DNR fisheries staff from sites on Lake Winnibigoshish throughout the summer. During a recent examination, two zebra mussel veligers were found in a sample collected in mid-July near the middle of Winnibigoshish.
June, July and August, when water temperatures stay above the mid-50 degree mark, are the prime months for zebra mussel reproduction. Fourteen more sets of Winnibigoshish water samples from June through August were examined and showed no additional veligers. Adult zebra mussels have not been found in the lake. Current winter conditions prohibit further inspections.
“Although no adult zebra mussels were found, it is prudent and proactive to list Winnibigoshish Lake as infested,” said Rich Rezanka, DNR invasive species specialist. “The size of the lake may delay locating an adult population, but the presence of veligers suggests there is likely a reproducing population in the lake. This listing will allow recreationists and other resource partners to be aware of the finding and take additional precautions to prevent inadvertent spread to other lakes.”
At 58,544 acres, Winnibigoshish is the fourth largest lake in Minnesota. The lake provides recreational opportunities to thousands of anglers throughout the year. Walleye, yellow perch, northern pike and even some muskie anglers from throughout Minnesota and the country fish these waters.
With the discovery of zebra mussels in this popular lake, anglers and boaters are reminded to be extra vigilant in ensuring their boat and other water-related equipment are clean before leaving a lake access.
Each person must take responsibility to help stop the spread of zebra mussels in lakes and streams and protect the state’s aquatic ecosystems. The DNR can’t do it alone. Boaters are required by law to pull the plug and drain all water. DNR officials encourage boaters to do this on the ramp where water will drain from the boat.
Lake Winnibigoshish (DNR public waters number 11-0147) and several other connected waterbodies will be designated as infested waters.
Connected waters include:
- Cut Foot Sioux Lake (public waters number 31-0857).
- Egg Lake (31-0817).
- First River Lake (31-0818).
- Little Cut Foot Lake (31-0852).
- Little Winnibigoshish Lake (31-0850).
- Pigeon River from the Pigeon Dam Lake’s dam to Lake Winnibigoshish.
- Rabbits Lake (31-0923).
- Ravens Flowage, which includes an unnamed creek from Township 146, Range 29, Section 3 to Township 146, Range 29, Section 11 and Raven Creek.
- Raven Lake (31-0925).
- Sugar Lake (31-0925).
- Third River downstream of Highway 33.
- Third River Flowage, which is part of Lake Winnibigoshish.
- Mississippi River from the Knutson Dam downstream to Little Winnibigoshish.
Further sampling will continue next spring and summer, including additional plankton tows, dives, shoreline searches, and coordination with resource partners on the lake and downstream waters to monitor for zebra mussels. The DNR is working cooperatively with the Leech Lake Band of Ojibwe on this veliger finding.
Some activities, such as bait harvest and transport of water for any purpose, are currently restricted in these waters due to their designation as infested with faucet snails. The new designation with zebra mussels will be effective upon publication in the State Register on Feb. 12, 2013, and may further restrict bait harvest activities.
For more information about aquatic invasive species go to www.mndnr.gov/ais.