The Minnesota Department of Natural Resources (DNR) confirmed that Fish Trap Lake, situated close to Motley in Morrison County, have been infested by aggressively invasive zebra mussels.
A lake user reported on Tuesday, June 30 that a zebra mussel was found adhered to a drenched tree branch close to the shore of the lake. A DNR aquatic invasive species (AIS) investigated and later confirmed that it was indeed a zebra mussel. The staff of the agency came to conduct surveys on Thursday, July 9 and discovered the presence of a solid population of adult species in the extensive regions of the lake. For this reason, the lake is not to be subjected for treatment. Further comprehensive investigations will be conducted in the area this week. Other shallow lakes with reported, isolated populations of zebra mussels have already undergone treatment.
"Fish Trap Lake is the first lake in Morrison County to be confirmed with zebra mussels," said Christine Jurek, DNR invasive species specialist in Sauk Rapids. "This new infestation underscores the need for continued diligence in complying with the state's laws to prevent and curb the spread of invasive species." Lake users such as boaters should be extra watchful in guaranteeing that their boats and materials are clean before leaving the lake, and that they should be reminded to communicate with the DNR immediately should they suspect any doubtful animals or plants in the bodies of water, Jurek adds.
Zebra mussels are small animals that are comparable to the size of a fingernail and specifically measure ¼ to 1-½ inches in length. These animals adhere itself to solid surfaces in the water and they have D-shaped shells that often have yellow and brownish stripes. Approximately 100,000-500,000 eggs are produced by female zebra mussels annually. The eggs grow in what is called "veligers," which are free-living, microscopic larvae that initiate the formation of the shells. The veligers immerse and adhere to solid surfaces using its "byssal threads" after two to three weeks.
Although an infestation report had been reported, majority of lakes in Minnesota remain free from any aquatic animal invasion and the areas infested with zebra mussels are less than one quarter of one percent of all lakes. Boaters and anglers are instructed to clean their boats of debris, remove drain plugs and properly throw unused bait in the garbage. Subjecting the boat to high-pressure water, rinsing it with hot water and drying it for at least five days are also highly recommended.
Jurek advises the people, who may have encounters with suspected invasive animals to perform helpful measures, which include putting the specimen in a safe bag or container, taking a photograph of the specie and sending it to the DNR via email, indicating the exact location where the specimen was found in a GPS device or lake map and letting the DNR know as soon as possible to coordinate transmission to the office. Upon the receipt of a report, the DNR will check if the specimen is indeed an invasive animal. Once confirmed, the staff will conduct a survey in the area. Possession of zebra mussels, unless those that are being transported to the DNR office, is prohibited.
Photo: andres musta | Flickr
