Zebra and Quagga Mussels
(Dreissena polymorpha and Dreissena bugensis)
These invasive mussels filter plankton out of the water, which depletes it as a food source for native species. Large colonies can take over fish spawning areas and beaches, cutting the feet of potential swimmers. They also clog water intake lines because of their dense colonies. Zebra and Quagga mussels can reduce water quality as they can increase the presence of toxic algal blooms, which can have health impacts on native wildlife. They latch onto boats and can be easily spread between water bodies.
They are native to eastern Europe and came over the great lakes in the late 1900s, supposedly from released ballast water of ships. The zebra mussels spread rapidly into the great lakes and some surrounding water bodies. However, the quagga mussels are more limited to the southern great lakes.
Impacts & Control
As mentioned above these mussels filter out large quantities of plankton which negatively affects native ecosystems. The large colonies of mussels can completely cover areas and impact fish spawning. They also hinder recreational activities such as swimming.
When using infected water bodies for recreation be sure to check your equipment, boat, trailer and vehicle for any signs of the mussels. This will prevent the spread to other water bodies.
A species that is actually benefiting from the zebra mussels is the Silver Chub as it feeds on the invasive species. The silver chub is a threatened species so the zebra mussels may actually be helping it recover.