Ukrainian mussels invading California

Quagga mussels, an exotic species native to Ukraine that was first found in the Great Lakes 18 years ago, have been found in a fifth San Diego County reservoir. Quaggas apparently were transported from Europe to Lake Erie in the United States in the ballast water of oceangoing ships, The San Diego Union-Tribune reported. The mussels grow virtually unmolested because they have no natural predators. They clog pipes and screens at power stations, water treatment plants and agricultural irrigation lines. Photo: New York Sea Grant