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Photographer: Amy Benson
Source: U.S. Geological Survey
Cover photo: TPWD Photo Archives

Zebra and Quagga Mussels

Dreissena polymorpha & D. bugensis

Origin: Native of Eurasia

Impact: Zebra and quagga mussels are highly invasive, small freshwater mussels that multiply 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 and quagga mussels are usually found in large clusters and usually have a zebra-like striped pattern on their shells. Zebra mussels will lie flat on a smooth surface on their hinge side, unlike quagga and native mussels. Once invasive mussels become established in a water body, they are impossible to eradicate with the technology currently available.

Spread: Zebra and quagga mussels originated from the Balkans Peninsula in Poland and the former Soviet Union. Since then, invasive mussels have become firmly established in Europe and have invaded much of the U.S. In 2009, the first adult zebra mussel in Texas waters was confirmed in Lake Texoma. Zebra mussels have since spread rapidly from the Red River basin to the Trinity, Brazos, Colorado, Guadalupe, San Antonio, and Rio Grande river basins. Quagga mussel larvae were confirmed in 2021 in Lake Amistad in the Rio Grande basin

Thirty-four Texas lakes across seven river basins can be currently (March 2025) classified as "infested" with zebra mussels, meaning that the water body has an established, reproducing population: Amistad, Austin, Belton, Bridgeport, Brownwood, Canyon, Dean Gilbert (a 45-acre Community Fishing Lake in Sherman), Diversion (private lake downstream of Medina Lake), Eagle Mountain, Georgetown, Granger, Grapevine, Inks, Lady Bird, Lewisville, Livingston, Lyndon B. Johnson, Marble Falls, Medina, Nasworthy, O.H. Ivie, Pflugerville, Placid, Randell (access for Denison residents only), Ray Roberts, Richland Chambers, Stillhouse Hollow, Texoma, Travis, Walter E. Long, and Worth. Lakes where invasive mussels or their larvae have been detected on more than one occasion but so far there is no evidence of a reproducing population are classified as “positive.” Lakes Amistad, Dunlap, Fishing Hole (a small lake connected to the Trinity River below Lake Lewisville), Lavon, and McQueeney, as well as river reaches downstream of infested lakes on the Colorado, Guadalupe, Lampasas, Leon, Little, Red, and Trinity rivers are classified as "positive" for zebra mussels. Lake Amistad in the Rio Grande basin is also classified as “positive” for quagga mussels in addition to being “infested” for zebra mussels. Zebra mussels have been found once in Lake Ray Hubbard, classifying this water body as "suspect". (See map) Several other lakes are considered "Inconclusive" due to recent DNA-only detections.

Experts fear they could spread to many other water bodies in Texas; biologists with Texas Parks and Wildlife Department and partners are monitoring many high-risk water bodies in Texas for the presence of invasive mussels.

Learn More:
Protect the Lakes You Love. Stop Invasive Mussels.
Zebra Mussel Profile Page

Report Form

If you have spotted Dreissena polymorpha & D. bugensis (Zebra and Quagga Mussels), use this report form to send an email to the appropriate authorities.

Your Name

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Did You Collect a Specimen?
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Comments: Describe the species, impact, infestation or generally what you are seeing.

Please upload a photo of the specimen or the site where the specimen was seen. NOTE: The photo file must be no larger than 2 MB in size.


NOTE: We are expriencing an issue in which after you click on the "Submit Report Now" button below, you will be directed to a blank page. HOWEVER, don't worry, your report will be submitted! (You may simply close the blank page.)

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