Lake Independence Citizens Association

What are zebra mussels and why are they a big deal? 

By Angela McLaughlin

     It’s time to face the facts: Lake Independence has zebra mussels, and the population appears to be growing. We hear it all the time – Zebra mussels are an invasive species. Zebra mussels are bad. You don’t want zebra mussels in your lake. Check your boat, check your dock. Report findings. But what exactly are zebra mussels and why does it matter that our lake has them? 

What are zebra mussels and how do you identify them? 

     Zebra mussels are a mollusk from Eurasia; they are not native to the United States. In Minnesota, zebra mussels were first found in Lake Superior in 1988. They have since spread to many lakes and major waterways, including the Mississippi River.  

     Zebra mussels get their name from the dark, zig-zagged stripes on their D-shaped shells. They range in size from ¼-inch to ½-inch long, about the size of a fingernail. They are filter feeders – the MN DNR reports that they can filter one quart of water per day, feeding primarily on algae. Females can produce up to 500,000 eggs per year. Adults can survive out of water – up to 21 days in wet conditions or less than five in dry conditions.

Photo credit: U of MN extension

Where do zebra mussels live? 

     They live underwater, attached to natural and manmade structures – logs, plants, boat lifts, swim rafts, rocks, etc. They may also carpet the lake floor. 

What benefits might be seen from zebra mussels? 

     Since zebra mussels are voracious filter feeders, algae in lakes may be reduced, bringing better water clarity. 

Why are zebra mussels bad? 

     On the surface, better water clarity from zebra mussels might seem like a good thing. However, they are so efficient at filtering that they outcompete with native species for these food sources, negatively impacting native species.
     Zebra mussels procreate quickly, attaching to and incapacitating native mussels, causing die-off in native species. 

     Since they attach to many surfaces (i.e. docks, boats, etc.), they impact humans in a couple of ways: swimmers may cut their feet on mussels attached to different surfaces, and they may encrust equipment, causing costly repairs. 

What should we do about them? 

It's everyone’s responsibility to prevent the spread of zebra mussels. This can be done by making sure to properly clean and drain all watercraft of aquatic plants and water, and dispose of unwanted bait, before moving to a new body of water. Zebra mussels are shade lovers – keep this in mind as you look for them on equipment or monitoring plates.

LICA partners with the DNR and Three Rivers to monitor zebra mussels in Lake Independence and has provided 12 volunteers with zebra mussel monitoring plates and instructions. If you find zebra mussels near your property, please report to Pat Wulff at rwulff106@gmail.com. 

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