Science / Uncategorized

Clean Water Superstar #2: Native mussels

Every month, the Clean Water Initiative Program will be highlighting a Clean Water Superstar. These are species that help keep our state’s water resources swimmable, drinkable, and fishable. January’s Clean Water Superstars are native mussels! Throughout the month, there will be information, resources, pictures, and videos about these superstar animals posted on the Clean Water Vermont Facebook page.


An eastern freshwater pearl mussel. Photo credit: Steve Fiske, Department of Environmental Conservation

Imagine you’re kayaking on a wide, slow-moving river. The water is clear and you look down as you paddle. The bottom is sandy with some gravel and rocks mixed in, but you notice that some of the “rocks” you’ve been seeing don’t look quite right. They are all about the same size, slightly cracked, and have a bit of what looks like algae growing out of the cleft. You drift closer to the shore and as the water gets shallower, you are able to get a better look and can see that these aren’t rocks, but native freshwater mussels, shells open to filter nutritious particles out of the water.

You are lucky to encounter these extraordinary mollusks. Of the eighteen species native to Vermont, ten are listed as threatened or endangered and only three are considered common. One of these common species can be found in the shallow waters of most Vermont lakes, but can occur in deeper waters as long as food, oxygen, and temperature are sufficient. The distribution and size of mussel populations in rivers and streams are more limited because habitats are more varied.


The diversity of native mussels in Vermont. Photo credit: Chris Fichtel, Vermont Fish and Wildlife Department

Mussels filter algae, bacteria, and detritus (dead organic material) out of the water by drawing it in when their shell is open and catching particles on their gills. In some lakes and large rivers near Lake Champlain and the Connecticut River where populations can become quite large, mussels filter out a significant amount of nutrients – in the form of organic material. Given Vermont’s goals for reducing phosphorus in Lake Champlain, this is an extremely important role. However, particles in the water can easily become too much of a good thing if you’re a native mussel. If there is a large amount of algae, sediment, or other material in the water, the mussels’ gills and other organs can become clogged. Mussels are therefore found largely in water that is already relatively clean and can be used as an indicator of a pristine watershed.

Native mussels are known for their ability to remove nutrients and thereby ‘clean’ the water, but they are themselves dependent on clean water to breathe and feed. They are indicators of clean water and a healthy ecosystem, and help to protect and maintain their pristine water habitat. So next time you’re out in your kayak, keep an eye out for January’s Clean Water Superstars.

For more information, visit the Clean Water Vermont Facebook page, and stay tuned for the next blog post about threats to native mussels.