Zebra Mussel (Dreissena polymorpha) and Quagga Mussel (Dreissena rostriformis)
Both zebra and quagga mussels are small fresh water mussels that were introduced to the United States through ballast water discharge of transoceanic ships. They are native to the Caspian Sea region of Russia, and spread to Europe through canals in the 1700s and 1800s. The quagga mussel was named after an extinct relative of the zebra, and is known by two scientific names: Dreissena rotriformis and as Dreissena rostriformis bugensis.
Environmental: Both zebra and quagga mussels are filter feeders. Their presence reduces the availability of tiny food particles (zooplankton and phytoplankton) in the water which serve as a primary food source in aquatic ecosystems. Furthermore, increased water filtration improves water quality which results in higher populations of aquatic vegetation that can become a nuisance for boating and recreation. Zebra mussels can also reduce native mussel and crayfish populations–as zebra mussels can attach to the shells and exoskeletons of these native species and suffocate them.
Zebra mussels promote the presence of blue-green algae blooms, caused by Microcystis species, which produce a group of toxins known as microcysins. Microcysins have been shown to cause death in both terrestrial and aquatic animals. In humans the toxin is believed to damage the liver. Below is a photo of an algal bloom that occurred in Sodus Bay, Ithica NY in 2010.
Impacts on Humans:
Mussel infestations can clog power plants and drinking water intakes. The effort to remove mussels from municipal plants can be costly to cities and power plants. Zebra and quagga mussels attach to boat motors and hulls, reducing boat performance, efficiency, and possibly causing the motors to overheat.
The zebra mussels can attach to rocks, swim rafts, and ladders where swimmers can get cuts on their feet from the sharp edges on their shells. The dead zebra and quagga mussels wash ashore and cause an unappealing aroma due to their decay. The presence of rotting mussels can cause swimming areas to be abandoned.
Identification for Zebra Mussel :
Found in freshwater attached to solid surfaces in clusters of 70,000 per square meter. They prefer algae-rich, shallow water ranging in depths of 6 to 30 feet.
Shape: D-shaped shell
Size: 1/4th to 1 ½ inches, roughly the size of a fingernail.
Color: Alternating black and white stripes.
Habitat: Found in freshwater attached to solid surfaces in clusters of 70,000 per square meter. They prefer algae-rich, shallow water ranging in depths of 6 to 30 feet. Zebra mussels are found in fresh water sources throughout portions of the US, with highest concentrations in northeastern regions.
Biology: Females can lay 1 million eggs per year. The microscopic larvae, veligers, take 2-3 weeks to attach to substrate. Adults can filter approximately 1 liter of water a day.
Identification of Quagga Mussel:
Quagga mussels are found in freshwater attached to solid surfaces in clusters of 35,000 per square meter. They are not as widely disbursed as zebra mussels but are found in fresh water sources throughout the US with highest concentrations in northeastern regions.
Shape: Rounder with a convex ventral side, will appear asymmetrical when viewed from this side.
Size: Larger than zebra mussel, usually 4cm.
Color: White, cream, or black alternating bands, the rings are usually paler in color closer to the hinge.
Biology: Females can lay 1 million eggs per year. The microscopic larvae, veligers, take 2-4 weeks to attach to substrate.
Control and Management:
Some pesticides are used in the control of zebra mussel, but they are not very effective. The DEC has created a protocol (hyperlink to dec: http://www.dec.ny.gov/animals/48221.html) for checking boats, trailers, and waders for invasive hitchhikers. The 5 steps for cleaning boats are to Check, Clean, Drain, Dry, and disinfect your boat. More information about disinfecting your boat can be found on the DEC website. (http://www.dec.ny.gov/animals/50267.html)
Click here to find out how long you should dry your boat depending on region. (http://www.100thmeridian.org/Emersion.asp)
Title photo: US Geological Survey. Zebra mussels suffocating native mussels photo:Randy Westbrooks, Invasive Species Prevention Specialist, (Bugwood.org).zebra mussel attached to native crustacean (priorlakesassociation.org). Algal bloom photo: Kara Lynn Dunn (waynecountylife.com). Dead zebra mussels on beach photo: United States Environmental Protection Agency Great Lakes National Program Office, USEPA, (Bugwood.org). Zebra and Quagga mussel distribution map photos: United States Geological Survey, (nas.er.usgs.gov). Zebra mussel on boat propeller photo: (waterfrontrestoration.com).
For a more in depth look at quagga mussel visit: (http://www.invasivespeciesinfo.gov/aquatics/quagga.shtml)
For more information on the zebra mussel visit: (http://www.invasivespeciesinfo.gov/aquatics/zebramussel.shtml)
For more information about algal blooms in Sodus Bay use:
Kara Lynn Dunn. “Wayne County Life.” NY Sea Grant Funds Lake Ontario Algal Bloom Research on Sodus Bay. Wayne County Life, n.d. Web. 12 Aug. 2015. <http://www.waynecountylife.com/2012/04/ny-sea-grant-funds-lake-ontario-algal.html>.