Show Me That Mussel!

Invasive vs Native Mussels: What’s the Difference?

When you work in the realm of invasive species, your first thought when hearing the word mussel is “uh-oh”. You start thinking, “Ok, which one? Zebra mussel or Quagga mussel?”. But then you remember that there’s a whole different kind of mussel; Wisconsin’s native freshwater mussels. These mussels are key indicators and drivers in healthy lakes, rivers, and streams.

Freshwater native mussels help our waters; each mussel can filter gallons of water a day, removing pollutants like mercury. A bed of mussels filtered more than 21 million gallons of water each day in the Upper Mississippi River! As a food source, species like raccoons, muskrats, otters, herons, and even some fish prey on these mussels. In addition, they can help stabilize riverbeds! There are over 50 species of native freshwater mussels in Wisconsin. So many varieties of shape and size! Some of them are quite large, similar in size to your phone. So how do these “good” (native) mussels differ from the “bad” (invasive) ones?

Unlike our native mussels, there are only two invasive mussels in Wisconsin; the Zebra mussel and the Quagga mussel. And they are both easy to identify! Both the Zebra and Quagga mussel are very small mussels (1/8 in. – 2 in.), only about the size of your thumbnail. As for coloration, the zebra mussel looks like it has stripes – just like a zebra! Meanwhile, the Quagga mussel are a little lighter in color but can have a large color variation.

So if you’re at a lake and you pick up a mussel, take a look at its coloration and size. If the mussel has zebra stripes and is the size of your thumbnail, you’re almost assuredly holding an invasive mussel.

Want to learn more about mussels? Check out some of our other posts on Zebra mussels and Quagga mussels. How did both the zebra mussel and quagga mussel get into the Great Lakes?

Photo Credit: John Karl, Jesse Weinzinger