Glen Lake Dodges Milfoil (For Now). But What About Those Koi?

The Glen Lake Association is breathing a sigh of relief after multiple extensive searches uncovered no signs of a problematic invasive plant that has wreaked havoc in other lakes in the region.

Association scientist Rob Karner tells The Ticker that after viewing all of the survey results, it does not appear that Eurasian watermilfoil (EWM) has a foothold in the lake.

“After viewing nine-plus hours of visual digital data from aerial drone work, underwater remote operated vehicle (ROV) work and numerous snorkel hikes on Little Glen and parts of Big Glen Lake, no EWM was found in the predetermined sites where there was aquatic plant growth,” he says.

The association began circling the wagons last fall after detached pieces of EWM were found floating in the water near the lake’s sole public boat launch. It wasn’t clear if the pieces came from another lake via an unwashed boat or if they were from a plant growing in the lake.

While it was too late in the season to mobilize a large-scale search, aerial surveying was completed that identified nearly 40 potential “hot spots” of plant growth. Two contractors were then hired to conduct searches this spring and summer.

The first worked by dragging a rake in a grid pattern, and the other used a combination of aerial drones and underwater ROVs to search for the plant. Though the vast majority of the work focused on Little Glen, which by virtue of its shallower depth has habitat much more conducive to EWM, crews also checked other areas.

“There was some concern that maybe the Crystal River had it, or maybe Fisher Lake or maybe vulnerable parts of Big Glen might have it,” Karner says. “So we did additional snorkel hikes with GoPro cameras and we spot checked additional spots beyond Little Glen, which was our first focus of the season.”

Not finding EWM doesn’t mean the association is resting on its laurels. Any boat at any time could bring it (or another nasty invasive) into the lake. Neighboring Lake Leelanau, for example, has been battling EWM for years.

"I don't think I'll ever rest easy when it comes to EWM," Karner says. 

Boat washes are among the best lines of defense against the spread of EWM and aquatic invasive species, which often spread from lake to lake as they hitch rides on or in boats. GLA has operated a full-service boat wash at the boat launch for many years, and Karner says it washed more than 1,000 boats in July of this year alone.

Aside from continuing to pour efforts into the boat wash, the association might need to so some regular montitoring, association President Stan Kryder says. 

“We've caught our breath, so to speak, and we breathe a little sigh of relief, and yet, at the same time, this is a baseline,” he says. “This is almost like starting our learning curve and establishing best practices of how we prevent it and how we have an ongoing monitoring process.”

Karner agrees. He wants "early detection and rapid response to be the battle cry."

“One thing is certain: we've got to come up with a protocol, some standard operating procedures and budget accordingly, for a year-after-year scan of the lake like we did this year so we can kind of keep handle on things at a 300 foot level,” he says. “We can now go from baseline surveying to trendline surveying and see how these aquatic gardens are fluctuating.”

EWM is far from the only invasive species in the news, particularly in Glen Lake. Reports of bright orange koi there have attracted a ton of attention in social and traditional media in the last month, bolstered by photos of bowfishermen holding massive specimens.

The association hired a bowfishing outfit out of Mesick (the Thundering Aspens Sportsman Club) to hunt these non-native fish. The club got four large adults (including one that might be a world bowfishing record for koi).

There might be a few more in the lake. For now, Karner says, the bowfishermen stand ready to come back out if there are more reports.

“We don't think we'll start up any new official hunts until the spring unless we get a call,” Karner says. “The media coverage has been far and wide, and people are thinking about it, and they’ve seen the pictures. There’s a ton of people around the lake who would get their phones out and call me if they saw one.”