Quagga Mussel – Oneida County Aquatic Invasive Species Program

Quagga Mussel  (Dreissena bugensis)

Identification: The quagga mussel is a freshwater bivalve mollusk. It’s appearance is similar to the zebra mussel (Dreissena polymorpha). Quagga mussels have a rounder appearance and a convex ventral side when compared to zebra mussels. They have colored rings on the white/cream shell that vary from brown to white colored. The rings are paler in color near the hinge. The opening hinge, when viewed from the front, is asymmetrical. Quagga mussels can reach up to 4 cm in size.

Ecology and Natural History: Quagga mussels are native to the Dnieper River drainage of Ukraine and the Caspian Sea. The species was introduced by a release of veligers during a ballast exchange in a ship. It’s dispersal once in the United States is due to its free-floating larval stage and its ability to be transported by bilge water and livewell water. Quagga mussels can stay alive for several days out of water. They have the ability of filtering about one liter of water a day!

Impacts of Introduction: Quagga mussel introduction impacts are very similar to zebra mussel introduction impacts. Quagga mussels are filter feeders and remove large amounts of phytoplankton from the water, decreasing the food source for zooplankton. Quagga mussels are able to rapidly colonize on hard substrates such as pipes and screens, which reduces their pumping capabilities. Their competition for resources has also stressed native clams and mussels, many of which are endangered.