Zebra Mussel (Dreissena polymorpha)
These mussels were a ballast water introduction from the Caspian Sea, first discovered in the Great Lakes in 1988. Zebra mussels quickly spread throughout the commercial shipping waterways of the Mississippi River and Great Lakes drainages. Colonization of inland waters has been slower, though the invasion rate is now increasing. Recreational boaters and anglers are the major vector for dispersal (Johnson and Padilla 1996; Johnson and others 2001), and studies of boater movement have been used to identify lakes likely to receive zebra mussel colonists (Padilla and others 1996). Zebra mussels have spread to a number of lakes in Wisconsin, though not all lakes in Wisconsin are capable of supporting zebra mussels. Many Wisconsin lakes lack the dissolved calcium concentrations required to support a zebra mussel population.
Zebra mussels are successful because they fill an empty niche in North American ecological communities. They physically modify the aquatic environment and habitats, earning them the label ‘ecosystem engineers’ (Karatayev and others 2002). They accomplish this by efficiently removing phytoplankton and other particles from the water column. Zebra mussels not only clear the water, but also excrete large amounts of organic material. This organic material accumulates on the lake bottom, enriching bottom algae growth. Economically, they are also among the most notorious biofouling organisms in the world (Ludyanskiy and others 1993), readily attaching to water intake pipes and other mechanical equipment, thereby damaging infrastructure. In addition, they adhere to (and kill) native mussels, accelerating the decline of our already imperiled freshwater mussel fauna (Ricciardi and others 1998).
References:
Johnson, L.E. and Padilla, D.K. 1996. Geographic spread of exotic species:
ecological lessons and opportunities from the invasion of the zebra mussel
Dreissena polymorpha. Biological Conservation 78: 23-33.
Johnson, L.E., Ricciardi, A. and Carlton, J.T. 2001. Overland dispersal of
aquatic invasive species: A risk assessment of transient recreational boating.
Ecological Applications 11: 1789-1799.
Karatayev, A.Y., Burlakova, L.E. and Padilla, D.K. 2002. Impacts of zebra
mussels on aquatic communities and their role as ecosystem engineers. Invasive
aquatic species of Europe - Distribution, impacts, and management. E. Leppakoski,
S. Gollasch and S. Olenin. Dordrecht, The Netherlands, Kluwer Academic
Publishers 433-446.
Ludyanskiy, M.L., McDonald, D. and MacNeill, D. 1993. Impact of the zebra
mussel, a bivalve invader. BioScience 43: 533-544.
Padilla, D.K., Chotkowski, M.A. and Buchan, L.A.J. 1996. Predicting the
spread of zebra mussels (Dreissena polymorpha) to inland waters using boater
movement patterns. Global Ecology and Biogeography Letters 5: 353-359.
Ricciardi, A., Neves, R.J. and Rasmussen, J.B. 1998. Impending extinctions of
North American freshwater mussels following the zebra mussel (Dressena
polymorpha) invasion. J. Anim. Ecol.