Quagga mussel
Dreissena rostriformis bugensis

Quagga mussel (Dreissena rostriformis bugensis) is a mollusk pest. It is a native of Ukraine and was first detected in Great Lakes in 1989.

Dreissena rostriformis bugensis is a small freshwater bivalve mollusk. Quaggas are prodigious water filterers, removing substantial amounts of phytoplankton and suspended particulate from the water. By removing the phytoplankton, quaggas in turn decrease the food source for zooplankton, therefore altering the food web. Impacts associated with the filtration of water include increases in water transparency, decreases in mean chlorophyll a concentrations, and accumulation of pseudofeces. Water clarity increases light penetration causing a proliferation of aquatic plants that can change species dominance and alter the entire ecosystem.