The Mississippi River flows 2320 miles through America’s heartland. Unfortunately, our great River is in trouble, from invasive species. An invasive species is a species that is not native, usually introduced by humans and which generally takes over the ecosystem in which it is introduced.

Just like the Asian Carp, the Zebra Mussel is an invasive species. Originating in the Caspian Sea in the Middle East, they were first found in Lake St Clare (a lake between Lake Huron and Lake Erie) in 1988. It is believed that they were brought over in the ballast water from boats traveling internationally. Boats take up water at the start of their journey and then they empty the water at the end of their journey, this helps the boat balance when on their long journey. Zebra Mussels are able to produce up to one million eggs per year; the sheer number of them makes it extremely difficult to control this species.

Zebra Mussels get their name from the tan and dark stripes across their shell. As adults, they are about one inch long and can live about four years. They are filter feeders that are able to filter up to a quart of water per day. Now that does not sound like such a bad thing, but because they are not native, they do not have any predators and are consuming all of the food that the other native filter feeders need to survive. This causes a major strain on the native species, because the native species are being starved and not able to reproduce to compete with the invasive species. In many cases, the mussels have caused a dramatic decrease on the population size of the native species.

The adult mussels group together on hard surfaces in the water, such as pipes, boats, or even other shells. Once they are attached to a hard surface they are nearly impossible to remove. Some Zebra Mussels have been found up to six feet thick piling on top of each other. The juvenile mussels are able to move freely in the water, which has allowed the mussels to move to previously uncontaminated bodies of water.

Not only do the mussels cause environmental damage, but also to many of the water treatment plants along the River, the mussels represent an economic hurtle.  The juvenile mussels settle in pipes and eventually clog them. Sometimes, it is so difficult to remove these mussels that the pipes have to be replaced. These extra costs can add up to be millions of dollars for companies.

Sometimes our natural environment works in mysterious ways. Because the Zebra Mussel is a filter feeder, it can increase water clarity, allowing more aquatic vegetation to grow at a deeper depth. This can provide more nursery habitat for young fish; which has lead to increases in smallmouth bass population in Lake St Clair. They provide food for some native species and some ducks have even adjusted their migratory habits to go where these mussels are living. This is providing more food for the ducks. Even with many species feeding on these mussels, they are still not able to reduce the population numbers; therefore these mussels are able to continue choking out many native species.

There are ways to help reduce the amount of Zebra Mussels in our waterways. One of the most extreme ways occurred in Omaha, Nebraska, the Zebra Mussels were taking over Zorinsky Lake. The Army Corps of Engineers drained the lake for nine months in order to eradicate the mussels. Currently, the lake remains closed, but is being refilled by Mother Nature, it is about 85% full and it is unclear whether their experiment was successful. Since we cannot drain a river, we need to work together to clean our amazing River of this mussel. Some ways to help prevent movement of this mussel is to be much more careful of what we put in the water. You can help by:

1. Cleaning your boats when moving from one body of water to the next.  When moving the boat is sure to clean the boat with warm soapy water.

2.  Refrain from dumping water from one body of water into a different body of water.  Because the juveniles are free moving they are able to float in the water.

3. Not eating them! It is suggested that these mussels are not to be eaten or used as bait, because they pick up all of the toxins in the water.

Thanks for doing your share in preserving the quality of the Mississippi River!


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