Practical information to identify and manage non-native, invasive plants and animals
The Quiet Invasion:A Guide to Invasive Species of the Galveston Bay Area
Dreissena polymorpha
| ITIS TSN: | 81339 |
| Presence: | Species of Concern |
| Habitat: | Aquatic |
| Native Range: | Black, Caspian, and Azov Seas |
Human Health
This species poses no known human health impacts.Prohibited Lists
All species of mussel belonging to the family Dreissenidae are legally classified in Texas as exotic, harmful, or potentially harmful. No person may import, possess, sell, or place this species into state waters except as authorized by a rule or permit issued by the TPWD. A person may possess exotic harmful or potentially harmful shellfish, only if the shellfish have been shucked (in the case of oysters) or otherwise removed from their shells.Introduction Pathways
A release of larval zebra mussels during the ballast exchange of a single commercial cargo ship traveling from the north shore of the Black Sea to the Great Lakes in the 1980s is presumed to be the likely vector of introduction to North America (McMahon 1996). Rapid spreading throughout the Great Lakes and major river systems was due to passive drifting of the larval stage and its ability to attach to boats navigating lakes and rivers (Benson and Raikow 2010).Geographic Distribution
As of 2010, zebra mussels are not found in the Lower Galveston Bay watershed. However, a population was found in June 2009 in Lake Texoma on the border of Texas and Oklahoma. A recently confirmed collection was made on the west prong of Sister Grove Creek, a part of the East Fork of the Trinity River, just north of Dallas (Robinson 2010). Zebra mussels are found in the Great Lakes, most of the large navigable rivers in the eastern U.S. and numerous inland lakes in the Great Lakes region. In all, this species is found in 27 states (Benson and Raikow 2010).Specific Primary Habitats
Zebra mussels are freshwater species found in lakes, slow current areas of rivers (less than 2 meters per second), and are known to foul many types of hard surfaces, including water intake pipes, boat hulls, and docks. They can tolerate low salinities up to 4 parts per thousand (therefore may be found in some estuarine habitats) and temperatures to approximately 29° Celsius. Zebra mussels cannot tolerate hypoxic (low oxygen) conditions (Benson and Raikow 2010).Ecological, Economic, or Social Impact
Zebra mussels filter organic and inorganic particles, competing with native filter feeders for food and can alter the nutrient regime of a water body. Increases in water clarity can induce increased photosynthesis by rooted aquatic plants, and negatively affect fish species that prefer slightly turbid conditions. Zebra mussels settle in high numbers on native mussels (Unionidaceae) leading to death (ISSG 2005b). Zebra mussels form dense assemblages and cause fouling problems for industries that utilize water from invaded habitats (e.g. zebra mussels can line the inside of water intake pipes, effectively blocking flow). Losses to industry and costs to control this species are estimated to total 1 billion dollars per year in the U.S. (Pimentel et al. 2005).Physical Description
Zebra mussels are a black or brown and white striped bivalve with byssal attachment (via secreted filaments) to hard surfaces. Individuals are small, with a maximum size of approximately 3 centimeters (ISSG 2005b). The shell is keeled, having an angle between the ventral and dorsal surfaces. Color patterns are variable, from almost pure black to unpigmented and a variety of striped forms.Reproduction Characteristics
Zebra mussels have male and female forms and fertilize externally; larvae are planktonic for several weeks before settling and attaching to a substrate. It is estimated that a female may produce up to 1.5 million eggs per year (ISSG 2005b). Fertilized eggs hatch after 1 to 2 days, followed by several stages of free-swimming planktonic veliger lasting 8 to 180 days. Larvae then settle, attach to substrate as juveniles, and mature in 1 to 2 years. Zebra mussels live 3-5 years (ISSG 2005b).Feeding
Zebra mussels are filter feeders of phytoplankton, zooplankton, and bacteria.Control
Since early detection is key to preventing the spread and establishment of this species, regional/local monitoring or surveillance is essential. Zebra mussels should not be imported or released in local waterways. If found in local waters, note the capture location, kill and freeze the fish, and notify the TPWD. Watercraft and other equipment moved from invaded water bodies should be thoroughly cleaned an inspected before being deployed into Texas waters.Lists
This species belongs to the following lists:
Images
To view a larger version of an image, click on the thumbnail. Small zebra mussel http://www.invasive.org/species/subject.cfm?sub=10567 (D. polymorpha). Photo courtesy of Amy Benson, U.S. Geological Survey, Bugwood.org. |
 Zebra mussels (D. polymorpha) encrusting a native clam (Amblema plicata). Photo courtesy of Randy Westbrooks, U.S. Geological Survey, Bugwood.org. |
 Three shells showing the range in color of the zebra mussel (D. polymorpha). Photo courtesy of U.S. Geological Survey Archive, USGS, Bugwood.org. |