1. Why Should I Care about Mussels?

All species are important to our web of life on planet Earth. Freshwater mussels are nature’s water filters -- a single mussel can filter several gallons of water per day. They clean our streams, lakes, and rivers as they feed on algae and other small food particles. They also provide food for animals like muskrats and raccoons; even early humans ate them. Since mussels are sensitive to environmental changes, they monitor the health of our rivers and streams; where you find mussels you usually find good water quality!

2. Are Native Mussels In Trouble?

Yes. Unfortunately, freshwater mussels are now one of the most imperiled groups of animals in North America. In America, 69 of 304 (23%) mussel species are listed as federally endangered or threatened.

3. What are Federally Endangered and Threatened Species?

The Endangered Species Act of 1973 provides an important tool for conservation of endangered and threatened species. Federally endangered species are so rare they are in danger of becoming extinct. Unfortunately, extinction is forever and once gone, a species can never return to our web of life. Threatened species are more abundant at this time but may become endangered in the future.

4. How Many Federally Endangered Mussels do we have on the Mississippi River?

On the Upper Mississippi River System, we have four federally-endangered mussels: the winged mapleleaf, the Higgins' eye, the fat pocketbook and the scaleshell.

Winged mapleleaf

Higgins' eye pearlymussel

Fat pocketbook

Scaleshell

Also, each of the five States bordering the Upper Mississippi River have a list of species which are considered to be threatened, endangered or of special concern to them.

5. What’s the Biggest Curent Threat to Mussels in the Upper Mississippi River System?

Right now it’s zebra mussels!

6. Where did Zebra Mussels Come From?

Zebra mussels are an exotic species that probably came to America in the ballast water of large ocean vessels traveling from Europe. They became established in the Great Lakes in the 1980s and entered the Upper Mississippi River System from Lake Michigan soon after.

7. How Do They Harm Native Mussels?

Zebra mussels attach to hard surfaces with thread-like structures called byssal threads that secrete a strong glue-like substance. They attach to underwater objects such as barge and boat hulls, trailers, and motors. They also attach to the hard shells of native mussels where they compete for food, interfere with movement and reproduction, or change habitat conditions.

8. So, What’s Wrong with a few Zebra Mussels?

A few zebra mussels would be tolerable. The problem is that zebra mussels have a high reproductive capacity. They reproduce several times a year and attach in mass quantities on mussel shells and other hard objects. They can literally “carpet the bottom” of the river with a layer of zebra mussels that may be a few inches to several feet thick. In 1993, densities were as high as 100,000 per square meter at a site on the Illinois River! If you were a native mussel, can you imagine trying to feed, breath, or reproduce under a layer of zebra mussels?

9. How Can I Help?

Learn to identify freshwater mussels in your area and where they live. Notify Federal or State Biologists if you see numerous dead or dying mussels which may signal changes in the health of the stream or river.
And keep your boat and gear clean of zebra mussels!
For more information on zebra mussels including a 3D view, go to
http://sgnis.org/3drotate/zebra.htm
Watch the video "Stop Exotics - Clean Your Boat"