Impact of Zebra Mussels as an Invasive Species By: Melissa Malmstedt

Background on Zebra Mussels Dreissena polymorpha Common name: Zebra Mussel Originally from Caspian Sea and Ural River Also native to the Balkans, Poland, and the former Soviet Union

Occurrences of Zebra mussels in non native areas Late 18 th century – early 19 th century spread throughout most of Europe May have arrived in North America via a European ship's ballast water came from Canada’s Lake St. Clair into lake Huron and Lake Erie populations in all of the Great Lakes found in Hudson and Illinois rivers found in Mississippi, Arkansas, Ohio, and Tennessee rivers.

Biology of Zebra Mussels Fresh water mollusks Bivalve Colonial Filter feeders –Inhalant and exhalant siphons –Feed on algae

Ecology of Zebra Mussels Optimal pH is between 7.4 and 8.5 High oxygen between 8-10 parts per thousand Temperatures between 17 and 25 degrees C. Impact many species. –Unionids –Decreased zooplankton

Ecology cont. Increase water clarity –Increase in light –Increase of macrophytes and macrophyte beds that serve nurseries for fish Prefer to attach to live unionids

Reproduction Females begin to reproduce around 2 years of age Broadcast spawning triggered by: –Chemicals produced by algae –Temperature around degrees C Can produce 40,000 eggs in a single reproductive cycle

Reproduction cont. 3 periods of life –Larval –Juvenile –Adult Larvae; planktonic during trochophore, straight hinged veliger, and umbonal veliger stages. Pediveliger stage (settlement takes place) is the final larval form.

Reproduction cont. Planligrade; stage between larval and juvenile periods. Juvenile –Development of fertilized egg to juvenile can take anywhere from days. –Change in morphology Adult –Considered an adult when sexual maturity is reached.

Settlement on Zebra mussel (Pediveliger stage)

Impact of Colonizing Zebra Mussels on Humans Clog pipes Hydroelectric and nuclear power plants Public water supply Other industrial facilities

Clogged pipe

Control of Zebra Mussels Chemical –Oxidizing Chlorination –Toxic pipes Copper, brass, and galvanized metals are toxic to zebra mussels. Biological –Bacteria –Predation Ducks Fish

Refrences Ackerman, J.D., Sim, B., Nichols, S.J., and Claudi, R. (1994). “A review of the early life history of zebra mussels (Dreissena polymorpha): Comparisons with marine bivalves.” Can. J. Zool. 72: Genthnera, F., Winsteada, J., Gilleta, J., Van, A. Vielb,J., Genoveseb, E., Singerb, S. (1997) “Effects of a molluscicidal Strain of bacillus alveion on digestive tubules of zebra mussels, Dreissena polymorpha” Journal of Invertabrate Pathology. 69: Jack, J.D., Thorp, J.H. (2000). “ Effects of benthic suspension feeder Dreissena polymorpha on zooplankton in a large river.” Freshwater Biology. 44: MacIsaac, H.J. (1996). “Potential abiotic and biotic impacts of zebra mussels on the inland waters of North America,” Am. Zool. 36: Rajagopal, S., Velde, G., Jenner, H. (2002) “Effects of low-level chlorination on zebra mussel, Dreissena polymorpha” Water Research. 36: Schloesser, D.W., Nakepa, T.F., Mackie, G.L.(1996) “Zebra mussel infestation of unionid bivalves (Unionidae) in North America.” Amer. Zool. 36: Tucker, J.K. (1994)”Colonization of unionid bivalves by the zebra mussel, Dreissena polymorpha,in pool 26 of the Mississippi River.” J. Freshwater Ecol. 9: ,Zebra Mussel Information System, U.S. Army Corps of Engineers