Flathead Lake Remains Healthy And Free Of Invasive Mussels

Aug 12, 2019
Originally published on August 12, 2019 3:09 pm

Flathead Lake continues to defy national trends as a healthy blue body of water that’s free of invasive mussels. That’s according to the director of the University of Montana’s Flathead Lake Biological Station, who gave his annual state of the lake address Friday. 

“So, what is that state of our lake? Flathead Lake citizens, our lake is blue,” Jim Elser said at the Bio Station’s open house. “We know that it’s been blue for a long time. I’ll tell you how blue it has been.”

Elser explained that a near record water clarity sample was just taken last week. The station has been measuring water clarity since 1977, and data continues to show that the lake’s waters aren’t becoming any murkier or changing colors, all signs that nutrient pollution remains in check. Phosphorus levels have actually been declining over the last 10 years.

Elser also said that the Bio Station is expanding its water clarity dataset through a citizen science program that kicked off last year.

“We got almost as much range of observations in one year just by going to different parts of the lake than we got in 40-odd years just measuring at mid-lake deep, our main sampling station,” he said. “That’s kind of cool to see that.”

Elser delivered the good news Friday that Flathead Lake remains invasive mussel free as well.

Monitoring efforts using advanced DNA detection technology continue. Elser said the station has the ability to detect extremely small zebra or quagga mussel DNA particles in the water within an hour of sampling.

“So, we do think if they got in like that side of Yellow Bay, we could localize it. You could bring in a curtain, seal it all off, hit it with this molluscicide and then keep hitting it, keep hitting it,” Elser explained, “and hopefully try to get them out, but there are no known examples of this.”

Elser said in the past, he wouldn’t think such a strategy would be effective, but a recent study detailed how zebra mussels were removed from a smaller system, giving him hope that small-scale removal is possible.

Copyright 2019 Montana Public Radio. To see more, visit Montana Public Radio.