Hunting for zebras: Students take on lake threat as project
Jefferson High School students in John Esbjornsson's environmental science classes got more than they bargained for on a recent field trip.
According to Esbjornsson, the students in his class have a great interest in the lakes of Douglas County and the impact that the recent invasion of zebra mussels have on the aquatic ecosystem.
The students contacted Nathan Olson, an invasive species specialist with the Department of Natural Resources (DNR) out of Fergus Falls.
They sent an e-mail to Olson with an action plan, which Esbjornsson said outlined how the students could help the DNR educate the public about zebra mussels and also help monitor the invasion of this type of exotic species.
The students decided they would help look for zebra mussels in Lake L'Homme Dieu and met with Olson and Anna Ness, watercraft inspection coordinator with the DNR, last week at the L'Homme Dieu Beach.
The students, along with their teacher and the two DNR representatives, combed the beach area nearby shorelines.
"Those kids found more than they expected," said Olson. "It was quite shocking."
Olson was referring to the number of zebra mussels that were found.
JHS junior Lucas Anderson, who contacted the newspaper about the zebra mussel project, said none of the students expected to find as many zebra mussels as they did.
"We found them right away," said Anderson. "You would find a group of rocks and then find a whole colony of zebra mussels."
The students, he said, not only found zebra mussels on rocks, but they found them on pop cans, fruit snack bags, weeds, sticks and more.
"They were on everything and anything they could cling to," Anderson said, noting that he, along with the other students, were quite surprised and shocked at the number of zebra mussels they found.
The ones they were finding, he added, were mostly small to medium size. Once in awhile, the group would discover a larger one, most likely an adult zebra mussel.
Olson was also surprised by the amount of zebra mussels that were found, which he couldn't even begin to put a number on.
"It was hard to find a rock that didn't have any on it," he said. "They were definitely abundant. Unfortunately, it was a really good year of reproduction."
Because they can reproduce so quickly, zebra mussels can disrupt the lake's traditional food chain. They filter water, taking out plankton, algae and other nutrients that smaller fish eat. This, in turn, reduces the amount of larger fish.
To date, zebra mussels have been found in not only Lake L'Homme Dieu, but also Lake Carlos and now, Geneva. Olson said they are also "knocking on the door" of Lake Darling.
"They are making their way around," he said.
Anderson said while studying about the exotic species in Esbjornsson's environmental science class, the students learned that the zebra mussels tend to reproduce at a rapid rate and that if 500 are found in one year, people can expect to find 5,000 the next year.
"Every year, the amount of zebra mussels goes up dramatically," he said. "That is why something needs to be done."
Anderson was glad that his class had the opportunity to go out and see for themselves how bad the problem is. He said that actually viewing the amount of zebra mussels in the water, and not just learning about them in a textbook, made him more interested in the subject and that he wanted to learn more about them.
"I encourage everyone to look for zebra mussels in our lakes," he said. "Something needs to be done. We need to get rid of them."
Olson said if homeowners find zebra mussels on items pulled from the water, for instance a dock or boat lift, they should let them dry out for at least five days to make sure the zebra mussels dry up. After that time, they can be carefully swept off or removed and thrown in the garbage.
If zebra mussels are found on any lake - besides those already listed as infested waters - the DNR wants to know about it. People can either call Olson at (218) 739-7576, extension 259 or call the DNR office in Glenwood at (320) 634-4573.
For more information about zebra mussels, visit the DNR website at www.dnr.state.mn.us.