Zebra Mussel – Oneida County Aquatic Invasive Species Program

Identification: The zebra mussel is named for the striped pattern of its shell. Adults are 0.25 to 1.5 inches long and have D-shaped or triangular shaped shells. They are stable on their flattened side and attach to solid surfaces using threads that extend from underneath the shell. Zebra mussel larvae, called “veligers”, are microscopic.

Ecology and Natural History: Zebra mussels are native to the Black, Caspian, and Azov Seas. The species was introduced by a release of veligers during the ballast exchange of a commercial cargo ship traveling from the Black Sea to the Great Lakes. Its rapid dispersal once in the United States is due to its free-floating larval stage, its ability to attach to boats, and its ability to be transported by bilge water and livewell water in larval form. Zebra mussels can stay alive for several days out of water. They can lay up to one million eggs in a spawning season! They are filter feeders and are capable of filtering about one liter of water a day.

Impacts of Introduction: Zebra mussels often form colonies on intake pipes, restricting or blocking their flow. Navigational buoys have been sunk due to the weight of the attached mussels. Boat’s engines or propellers have been damaged due to attached zebra mussels. The biomass of phytoplankton is reduced drastically following the introduction of zebra mussels. Reductions in zooplankton biomass may increase competition, decrease survival, and decrease biomass of planktivorous fish. The competition for food has also stressed out native clams and mussels, many of which are endangered.

There are no confirmed populations of zebra mussels in Oneida County at this time!