There is something lurking under the water in Velvet and Flannery lakes west of Rhinelander. And it may come to the surface soon making boating, swimming and fishing difficult on the lakes. And area youth may be the best hope as a way to combat it.
“It is like a fishing net,” Flannery Velvet Lake Association president Paul Kern said. “Imagine getting something like that in your propeller. You can’t swim in it. If you try to fish, you can’t through it to get into the water.”
What is causing all these problems is large purple bladderwort and the lake association has been dealing with the issue for more than 10 years.
Large purple bladderwort is not an invasive species but has been causing problems on Velvet and Flannery lakes along with another lake in the area.
“We call it a nusiance plant,” lake association past president J.R. Barttelt said. “It is not rooted. It is a carnivorous plant that feeds on zoo plankton. It keeps blue green algae out of the lake by eating so much zoo plankton.”
The problem with large purple bladderwort is that on Velvet and Flannery lakes, the plant is rising to the surface in large amount, creating areas on the lake where boating and swimming are impossible.
“There were islands of this stuff floating in lake Flannery,” Barttelt said.
In 2003, the association contacted Susan Knight from UW-Madison who is stationed at Trout Lake in Vilas County. Knight had written a paper on large purple bladderwort in college and was one of a few people to study the plant.
“We had a study done and put a management plan in place,” Barttelt said. “They recommended a follow up study every five years.”
Those follow up studies showed a huge plant population existing at the bottom of the lake. The issue was that some years, the amount of material floating up was less and some years it was more.
“Nobody knows why it is coming to the surface,” Kern said. “The plant dies when it comes to the top but we don’t know if it is dying before it rises or after. No one knows. The DNR doesn’t know.”
What is concerning to the lake association is that it appears that large purple bladderwort is on the rise again in the lakes after declining for most of the last decade.
“We had seen less of it,” Barttelt said. “But the last few years it seems to be increasing.”
The lake association set up a citizen’s water monitoring group to collect more data on what could possibly be affecting the plant and what is making it come to the surface.
As part of that study, the lake association will partner with the UW-Extension office and youth coordinator, Lynn Feldman.
“I received an integrative grant for a project,” Feldman said. “The Extension focuses on getting kids into the environment. Getting kids geared toward stewardship toward natural resources. And build relationships between kids and adults.”
Feldman and the lake association is looking for youths to take canoes along with GPS devices to measure where the large purple bladderwort islands are located on a weekly basis.
“We will have two youth per boat with an adult to go out and measure where the floats are which will be put into a DNR database,” Feldman said. “The study will go on for about six weeks and we will send out a group once a week.”
Feldman said the group is looking for youth in eighth grade or older so she knows they will have to work around summer schedules. Which is one reason, she would like to have several youth signed up for the program.
“We know we have to work around youth schedules so we would like to have several signed up for the program,” Feldman said.
The large purple bladderwort floats begin appearing in mid July during a typical year so there is still time for interested youth to sign up.
The Extension has two canoes but others have volunteered their canoes on the lake.
“We had a meeting the other night and eight to nine people volunteered their canoes,” Kern said. “The home owners on the lake are behind this project.”
For more information or to sign up for the program, call Feldman at 715-365-2750 or email firstname.lastname@example.org.