The Zebra Mussel: An Introduction


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Figure 1: Zebra Mussel biofouling in pipe


Zebra Mussels, or Dreissena polymorpha, are small freshwater bivalve mussels that have become one of the most prevalent biofoulers in the world. The zebra mussel, which originated in the southeastern lakes of Russia[1] , has become an invasive species in many bodies of water worldwide. The mussels are spread unintentionally in the ballast water of transoceanic ships or on the hulls of river boats. Zebra mussel populations have successfully been established in Great Britain (1824), The Netherlands (1827), The Czech Republic (1893), Sweden (1920), Italy (1973), the Great Lakes in the USA (1988), and California (2008)[2] .


Zebra mussels are notorious for clogging water intake systems of industrial facilities, including power plants, water treatment facilities and irrigation systems. Zebra mussels will colonize on almost anything solid, especially rocks, boat hulls, piers and buoys, attaching by their strong byssal (filament) threads. The clogging caused by these organisms leads to greatly increased maintenance cost for water treatment plants that use water taken from mussel infested regions. It requires more energy to pump water through pipes with mussels colonies[3] , this means an increase in the carbon footprint of water treatment plants. With the attachment of mussels to boats engines become clogged, boat steering becomes more difficult, and more drag is created leading to overheating and engine malfunctions[4] .
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Figure 2: Zebra mussel biofouling on propeller

Zebra mussels can also negatively impact the ecosystem by displacing and killing other native mussel species, by attaching on top of them and competing for their food. Zebra mussels are filter feeders, which means that they feed by filtering and ingesting suspended matter and food particles found in the water. The filtering capacity of zebra mussels has been estimated at 10 to 100 ml/individual/hour[5] .The effective removal of phytoplankton by the mussels is a negative side effect, as plankton removal improves water clarity, allowing light to penetrate to greater depths in water bodies and altering the species composition of aquatic plant communities in the ecosystem. Thus, the natural ecosystem is disturbed and negatively affected by the introduction of zebra mussels.

In 2007, the U.S. Geological Survey estimated that the annual economic cost of controlling zebra mussels in the Great Lakes surpasses 5 billion dollars. Current methods of controlling zebra mussels are diverse, ranging from chemical and biological controls, thermal treatments, using natural predators such as crayfish[6] , high pressure water jets, and manual scraping. BioBullets are a new method of delivering toxins to zebra mussels that are potentially much more effective than traditional treatments.

Chemical treatments are commonly used to treat zebra mussels and are favored by industry. However, when mussels sense poisons in the water, they often close their shells for up to 3 weeks, preventing chemical treatments from being quickly effective. Therefore, high concentrations and long dosing times are needed, resulting in high costs. Chemicals which have been fairly successful in controlling organisms include chloramines, hydrogen peroxide, chlorine dioxide, potassium permanganate, ozone, and inorganic salts, such as potassium chloride[7] . Of all treatments, chlorine has been shown to be the most efficient and inexpensive method of treating zebra mussels.
  1. ^ Ludyanskiy, M. L., McDonald, D., & MacNeill, D. (1993). Impact of the zebra mussel, a bivalve invader. BioScience, 43(8), 533-544.
    Retrieved from: http://www.jstor.org/stable/1311948
  2. ^ Hoddle, M. (2011). Quagga dreissena rostriformis bugensis and zebra dreissena polymorpha mussels.
    Retrieved from http://cisr.ucr.edu/quagga_zebra_mussels.html
  3. ^ Edwards, B. (2011). zebra mussels battle biobullets’s toxic pellets in water plants. Bloomberg.
    Retrieved from: http://www.bloomberg.com/news/2011-09-04/zebra-mussels-battle-biobullets-s-toxic-pellets-in-water-plants.html
  4. ^ Hoddle, M. (2011). Quagga dreissena rostriformis bugensis and zebra dreissena polymorpha mussels.
    Retrieved from http://cisr.ucr.edu/quagga_zebra_mussels.html
  5. ^ Claudi, R., & Mackie, G. (1993). Practical Manual for the Monitoring and Control of Macrofouling Mollusks in Fresh Water Sys. CRC.
  6. ^ Martin, G. W., & Corkum, L. D. (1994). Predation of zebra mussels by crayfish. Canadian Journal of Zoology, 72(11), 1867-1871.
    Retrieved Fromhttp://www.nrcresearchpress.com.ezproxy.lib.ucalgary.ca/doi/abs/10.1139/z94-254#.UHzUYW-HIuc
  7. ^ Claudi, R., & Mackie, G. (1993). Practical Manual for the Monitoring and Control of Macrofouling Mollusks in Fresh Water Sys. CRC.