Origin: Native of Russia
Impact: The zebra mussel is a highly invasive, small freshwater mussel that multiplies rapidly and can cause tremendous environmental and economic damage. Their larvae are microscopic, and the adults are usually less than 1 1/2 inches long. Zebra mussels are usually found in large clusters, have a salient zebra-like striped pattern on their shells, and lie flat on a smooth surface, unlike many other mussels. According to the online National Atlas of the United States, "Once zebra mussels become established in a water body, they are impossible to eradicate with the technology currently available."
The spread of zebra mussels: Originally from the Balkans, Poland and the former Soviet Union, zebra mussels are firmly established in Europe and have invaded much of the U.S. On April 3, 2009, the first adult zebra mussel in Texas waters was confirmed in Lake Texoma. Zebra mussels have spread from the Red River basin to the Trinity and, most recently, the Brazos river basin.
Nine Texas lakes can be classified as "infested" with zebra mussels, meaning that the water body has an established, reproducing population: Belton, Bridgeport, Dean Gilbert (a 45-acre Community Fishing Lake in Sherman), Eagle Mountain, Lewisville, Ray Roberts, Stillhouse Hollow, and Texoma. Randell Lake, near Texoma, was known to be infested since 2014 but was officially designated as such in 2017 because public access was reopened (for Denison residents only). Eight other water bodies are classified as "positive" for zebra mussels, because zebra mussels or their larvae have been detected on more than one occasion but so far there is no evidence of a reproducing population. These water bodies are Fishing Hole (a small lake connected to the Trinity River below Lake Lewisville), Lavon, Livingston, Waco, Worth, Leon River below Belton, Red River below Texoma, and the Elm Fork of the Trinity River. Zebra mussels or their larvae have been found once in recent years in three Texas lakes - Cedar Creek, Fork, and Ray Hubbard - therefore these water bodies are classified as "suspect". (See map) Six lakes are now considered "Inconclusive" due to 2016 DNA only detections: Buchanan, Canyon, Georgetown, Grapevine, Somerville and Tawakoni.
Experts fear they could spread to many other water bodies in Texas; biologists with Texas Parks and Wildlife Department and partners are monitoring many water bodies in Texas for the presence of zebra mussels.
If you have spotted Dreissena polymorpha (Zebra Mussels), use this report form to send an email to the appropriate authorities.