BEAVER LAKE – A peculiar scene unfolded along the shore of Beaver Lake, just west of Whitefish, on a recent Monday morning. As the sun burned through the early fog, a pair of boats slowly followed a steady stream of bubbles. All eyes were trained on the diver producing the bubbles. Suddenly, Sara Wilkinson emerged from the murky water with a fistful of green weeds.
“How far is it?” someone on the boat asked.
“It’s dense,” Wilkinson responded.
Officials and scientists from local government agencies and nonprofits had gathered at the Beaver Lake fishing access to try to remove a small patch of Eurasian Watermilfoil that had been discovered a few weeks earlier on the lake bottom. The aggressive, non-native aquatic weed was first spotted in Washington state in the 1970s and has become a major problem in the Midwest. Up until a few years ago, lakes and waterways in Montana had not seen the weed, which can choke out native aquatic plants, destroy fisheries and inhibit recreation.
The patch found at the bottom of Beaver Lake – which was estimated to be about 25 square feet – was the first to be discovered in the Flathead Basin of Northwest Montana. Previously some had been found along the Missouri River and in a body of water near Thompson Falls. Addressing the issue while it is still small is crucial, according to Erik Hanson of the Flathead Aquatic Invasive Species Workgroup.
“It chokes out everything in small lakes,” he said. “It can cover everything, prevent recreation and kill fish.”
Hanson said property along lakes infected with the plant lose value, sometimes up to 15 percent and, because of that, those who live nearby should be vigilant in their preventive efforts. The most common ways Eurasian Watermilfoil gets into a lake are either from a boat that has recently gone through an affected area or by people dumping their aquariums into the water.
The aquatic weed looks like a long, green vine and when it breaks apart, small “wisps” can root into the water bottom and, depending on the conditions, can multiply into millions of new plants within a few years. Hanson said it’s unknown when or how the plant got into Beaver Lake, but considering the conditions it was likely a few years ago.
“That’s one of the scary things – where did this come from?” Hanson asked. “Was it a dumped aquarium or someone’s boat that was in an affected lake?”
Gordon Jewett, head of the Flathead County Weed, Parks and Maintenance program, said the weed patch was first discovered by a Department of Natural Resources and Conservation crew that was working near the lake. After confirming it was Eurasian Watermilfoil, the county – along with Montana Fish, Wildlife and Parks, the invasive species workgroup and the Whitefish Lake Institute – devised a plan to pull as much of the weed as they could before covering it with a mat to confine it to one area. Jewett said they were lucky to have been able to find it when they did and respond so quickly.
“In Flathead County we want to keep it in one spot. Our goal is to eradicate it,” he said. “It doesn’t belong here and we don’t want it here.”
Hanson said Montana has had very few problems with invasive plants and, because of that, it is important to address outbreaks as quickly as possible when they do appear. It was an opinion backed up by Thomas Woolf, the aquatic plant program manager for the Idaho State Department of Agriculture.
Woolf said Eurasian Watermilfoil has been a major problem across the Northwest, especially in Washington and Idaho. Since 2006, the state of Idaho has treated more than 10,000 acres of water affected by the plant and spent $9 million during that time. Woolf said the plant is a problem that can quickly get out of hand and is a danger to the public. He referenced an incident a few years ago when someone was trapped in a patch of the weed and drowned. However, he said the problem has been larger in the Midwest, where he went to graduate school.
“I’ve seen lakes that have been dominated by this (plant),” he said. “It looks like you can walk across it.”
Hanson said all of the groups involved with last week’s operation to pull and cover the weeds at Beaver Lake had the same goal: Prevent what has happened in other states from happening in Montana.
“The good thing is that we got here and dealt with it when it was small,” he said.