Zebra Mussels (Dreissenia polymorpha)
Key Identification Features
Description
Zebra mussels sometimes have a zig-zag striped pattern of brown and white, but they can have varying coloration all the way from completely dark to completely light. They are small mussels that attach themselves to hard surfaces using sticky threads from under their shells. This species has one flat edge that distinguishes them from the other invasive Dreissenid mussel, the Quagga mussel. Zebra mussels can sit flat on a surface on this one edge, whereas Quagga mussels are a bit rounder all around. Like any other filter feeder, the zebra mussel sucks in the surrounding water to filter for its nutrients, but they are so good at this that they significantly decrease availability of phytoplankton and zooplankton in the invaded habitats.
Native Range
Zebra Mussels are native to Eastern Europe from drainage basins of the Black, Caspian and Aral seas. They likely arrived in our region due to ballast water from ships.
Habitat and Dispersion
Zebra mussels are tolerant of a wide range of conditions. They are usually found in waters between 68 to 77 degrees Fahrenheit and in still to slow moving water. They are generally a freshwater species, however they can adapt to accommodate for brackish conditions. The mussels are spread by boats, waterfowl, and other animals. Anglers can also transport larval stage dreissenia in the water of their bait buckets.
Best Management Practices
Once zebra mussels are established, they are hard to eliminate without harming other organisms in the ecosystem. It is best to prevent their spread preemptively through proper watercraft cleaning methods. Cleaning the boat after use and allowing it to dry is the most effective measure for minimizing the spread. Remembering to drain bilges and live wells also prevents spread of the larval stage.