Zebra Mussel - Dreissena polymorpha


Interesting Facts


-Zebra Mussels are reproductively mature within 1 year and females can produce up to 30,000 eggs in first year of their life.

-The shell of their trochophore larvae forms within 2 to 9 days of fertilization.

-Zebra Mussels were most likely to be brought to America as larvae in ballast of water of ships that traveled from fresh water Europe to the Great Lakes.

-They were first found in Wisconsin waters of Lake Michigan in 1990.

-Zebra Mussels were first found in 1991 in the Pool 8 of the Mississppi River.

-Zebra Mussels are only freshwater mollusks that can firmly attach themselves to solid objects.

-In 2001, Wisconsin Electric Power Company reported they were spending 1.2 mil a year in control of zebra mussels on their Lake Michigan power plants.

-They are the only freshwater bivalve that is known to have a free swimming veliger larva.

-Zebra Mussels are generally thought to only have striped patterns, but they can range anywhere from all black, all white, and even tan.

-The invasion of the Zebra Mussels was one of the most important invasion in Biology.

-Zebra mussels can tolerate only slight salinity. Although some populations of European zebra mussels can be found in estuaries, their persistence is only because of reduced tidal fluctuation.

-There are many methods that have been tested in order to control the spread of Zebra Mussels. Some of these methods work better than others depending on the situation.




         -Chemical Molluscicides: Oxidizing (chlorine, chlorine dioxide) and Non-           oxidizing
         -Manual Removal (pigging, high pressure wash)
         -Dewatering/Desiccation (freezing, heated air)
         -Thermal (steam injection, hot water 32oC)
         -Acoustical Vibration
         -Electrical Current
         -Filters, Screens
         -Coatings: Toxic (copper, zinc) and Non-toxic (silicone-based)
         -Toxic Constructed Piping (copper, brass, galvanized metals)
         -CO2 Injection
         -Ultraviolet Light
         -Biological (predators, parasites, diseases)

The Wisconsin DNR has a great list of controlling Zebra Mussels once they invade.

-Chemical control the most common treatment by water utilities and power plants.

-Females can lay over one million eggs in a spawning season.

 -They can withstand short periods (several days) out of the water if conditions are moist and humid.

-They have a saltwater relative, the dark false mussel (Mytilopsis leucophaeata), which is native to the Atlantic coast.  This relative looks very much like the zebra mussel and is often mistaken for it.

-Zebra Mussels could possibly affect our drinking water. They may promote the growth of a blue-green algae that produces a toxin harmful to people and animals.

-Alternating dark and light stripes on their shells that range in color from brown to black and white to yellow.

        -The external shell patterns in relevance to other related species can be viewed on this page.

-After a Zebra Mussel dies, its sharp shells wash onto shore and can cause cuts when humans step on them.

-The Zebra Mussel's reproductive system is unique to freshwater mussels. The different stages of the Zebra Mussels life cycle can be viewed on the adaptation page.

-They require well oxygenated water with high levels of suspended organic material and a reasonably hard substrate in order to survive.

-Zebra Mussels require calcium in their diet in order to enable shell development.


Curious as to how Zebra Mussels interact with other organisms? View the interactions page to find out!