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Mussel beach: Students track zebras in Alexandria

Echo Press photo by Heather Huwe Students in John Esbjornsson's environmental science class looked over the zebra mussels they found at Lake L'Homme Dieu.

John Esbjornsson, a teacher at Jefferson High School in Alexandria, took his class to the beach Tuesday. But it wasn't to have fun in the sun. The class is studying current environmental events such as the Gulf oil spill and the local news of zebra mussels in the lakes area.

The environmental science class is in an invasive species unit and it went out to Lake L'Homme Dieu to collect data and also listen to Nathan Olson, an invasive species specialist for the Department of Natural Resources (DNR) in Fergus Falls.

Olson gave information about the zebra mussels and said they will soon be reaching maturity and re-populating.

The students observed the number, size and the objects the zebra mussels are attaching to.

The mussels attach themselves to hard surfaces. The students found the mussels clinging to everything from small rocks to a 16-inch rubber bungee cord that student Cody Larson found.

Olson was surprised that mussels were found attached to a glass bottle. Another odd item the mussels had attached themselves to was a plastic bag. Olson was also taken aback that the mussels had grown over other mussels.

On one of the small rocks, the students counted 68 zebra mussels. Most of the mussels the students found were in a depth of three to four feet of water.

Esbjornsson said the native clams and large snails were covered with mussels.

At Rotary Beach, the students found fewer mussels. Esbjornsson said this might be due to the lack of rocks, snails and clams. Though there were not many mussels at Rotary Beach, the students did find a branch covered with them. The students also found a number of mussels at the channel and at the public access.

Students from last semester's class had gone out in the fall to search for zebra mussels. This spring semester's class observed the difference between last semester's collection and their findings. Esbjornsson said there are more and larger mussels than when he took his fall class to the lake.

Olson agreed the mussels had definitely grown larger compared to last September when the same field trip was done with the other class. He also said the zebra mussels will be able to reproduce this summer and only time will tell how many of the larval mussels will survive the summer.