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
lakes, and rivers as they feed on algae and other small food particles.
They also provide food for animals like muskrats and raccoons;
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
the Higgins' eye, the fat
pocketbook and the 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
for food, interfere with movement and reproduction, or change habitat
8. So, What’s Wrong with a few Zebra
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
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
the video "Stop Exotics -
Clean Your Boat"