Zebra mussels found in Comfort Lake

Photo and graphic courtesy of the Comfort Lake – Forest Lake Watershed District
A team of volunteers and interested organizations scouted Comfort Lake in late July looking for zebra mussels.

The Minnesota Department of Natural Resources announced July 27 that zebra mussels have been found in Comfort Lake near Wyoming. Bill Keilty, longtime Comfort Lake resident and a board member on the Comfort Lakes Association, confirmed that the aquatic invasive species found only affected Comfort Lake, not Little Comfort Lake.

Zebra mussels originated in eastern Europe and can create a nuisance by clinging to solid structures underwater, clogging pipes or impeding boat motors.

The lakes association first got word of a possible mussel infestation shortly after July 4, when a lakeshore owner took a picture of a small creature she thought might be a zebra mussel and sent it to Keilty.

“I looked at it and I said, ‘It (doesn’t) look like a zebra mussel,’ but then we shared it with the (Comfort Lake – Forest Lake Watershed District),” Keilty said. “They in turn shared it with (lake scientist) Steve McComas and the DNR, and they thought it was.”

Watershed district program assistant Mike Sorensen said that the district was first notified about a possible mussel on July 13. Shortly before mussels were found in Forest Lake in 2015, the district had hired McComas’s company, Blue Water Science, to craft a rapid response plan for what to do if zebra mussels are found in a lake. On Comfort Lake, as in Forest Lake, the plan dictated a search of the lake to discover if more mussels could be found.

In late July, McComas, the district, the DNR and several Comfort Lakes Association volunteers were out on the lake and found a single adult mussel in three different locations around the northern area of the lake. Previously, mussels had been found in two other locations by a lakeshore owner, bringing the total number of locations to five. Keilty was somewhat surprised that adult mussels were found, as he keeps a ceramic plate “trap” that he uses to check for zebra mussels in the water and has yet to see any.

Sorensen the source of the mussels is a mystery, since Forest Lake drains into Comfort Lake.

The blue dots on the map are where the team searched and did not find any mussels; the red dots are where a mussel was found either by searchers or a lakeshore resident.

“We are not really sure if the mussels came in from Forest Lake or it they came from a boat,” he said, noting that the more likely possibility is that they came from a boat carrying infested water, as Forest Lake’s water must pass through a wetland before arriving in Comfort.

Since the mussels that were found are already adults, they are already reproducing, and there is little anyone can do within current scientific advances to eliminate them from the lake waters, but Keilty said lake residents should take heart in the composition of the lake floor, which is mostly mud and sand.

“Because of (the lake’s) bottom structures, it’s going to be really hard for (mussels) to establish,” he said. A rocky lake bottom would be a better home for the mussels, which attempt to cling to hard surfaces underwater. According to a study done by McComas, some limited mussel growth will likely occur closer to the shoreline of the lake, while the middle of the lake has oxygen conditions that won’t support mussel life.

As to what the Comfort Lakes Association plans to do regarding the zebra mussel infestation, Keilty said, “that’s kind of still up in the air.”

Sorensen suggested a putty knife as an effective way to clear mussels off submerged equipment like docks, and he added that there are multiple ways to rake and gather mussels from the lake floor close to shore (disposing of the mussels requires a DNR permit). The mussels, as well as the ongoing infestation on the lake by Eurasian watermilfoil, will be discussed at the association’s monthly meeting at 7 p.m. Aug. 10 in Wyoming United Methodist Church.

Keilty said he is skeptical of receiving meaningful assistance from the DNR because he feels the department has been unresponsive or unhelpful when past lake problems have come up, including the watermilfoil infestation. He would like the DNR to assist the association with night fishermen on the lake, which he believes are helping to spread the watermilfoil at a faster rate. Wyoming Mayor Lisa Iverson will also be at the Aug. 10 meeting, and Keilty said the association may also speak to her about the invasive lights of the fishermen.

Sorensen said that now that the mussels have arrived on the lake, the district’s job now shifts to education in order to prevent the species from infesting other lakes in the area; based on current information, the district believes Comfort Lake is the first lake in Chisago County to be infested by zebra mussels. He wanted to remind boaters about the rules for keeping aquatic invasive species from spreading: Clean your boat, drain your boat, dispose of your bait between lakes and let your boat dry between lakes.

Sorensen said that some lake residents in the district feel resigned to the spread of invasive species and wonder why the district and area lake associations spend money working to staunch the tide of new species. In reply, he’ll readily list off multiple invasive species that, due to prevention, haven’t yet made it to the area – some, like the dense mats of starry stonewort algae, that are far more onerous than zebra mussels.

“(This) is why we bother with any of this still,” he said.

He also hoped to assure Comfort Lake users that a zebra mussel infestation doesn’t mean the end of a usable lake. While the sharp, clumping mussels can be a nuisance, he said, lake life will still go on.

“Forest Lake is a great example of how a lake that has zebra mussels can still be enjoyed by so many,” he said.