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Dahlgren, J., 1994. "Exotic Species Profile -- The Zebra Mussel", University of New Hampshire Cooperative Extension, Maine/New Hampshire Joint Sea Grant College Program Exotic Species Profile -- The Zebra MusselThe zebra mussel, a freshwater mollusk native to eastern Europe, has raised much concern in North America in recent years. Like some other non-indigenous species, zebra mussels were probably carried here in the ballast water of transoceanic ships. Since their introduction and establishment in the Great Lakes basin and Canadian freshwater systems, the thumbnail-sized mussels have disrupted ecosystems and generated millions of dollars in damage to shoreline facilities and residences. The zebra mussel was first sighted in 1988 in the United States in Lake Saint Clair, which is between Lake Huron and Lake Erie. Since that time, its range has expanded to many other lakes and rivers. The prolific nature of zebra mussels results in a rapidly growing and spreading population. A mature female can produce from 30,000 to 1,000,000 eggs per year. The newly hatched larvae called veligers are free swimming and nearly invisible. Between two and three weeks, the mussels' shells begin to harden. The young mussels "settle," attaching to a variety of hard surfaces including each other. Within their first year, the mussels can detach and reattach to surfaces such as rock, wood, glass, rubber, fiberglass, metal, gravel and native shellfish. Adult mussels secrete strong byssal threads, which secure their attachment to these surfaces. As the mussels continue to settle and grow, colonies form. These colonies can clog water intake pipes and screens at drinking water facilities, industrial facilities and power generating plants. Zebra mussels flourish in intake pipes at industrial and residential shoreline properties because the pipes provide a source of protection as well as a constant supply of food in the continuously flowing water. Zebra mussels can also impact commercial and recreational boating by fouling navigation buoys and boat hulls, and by clogging the cooling systems of boat engines.
The rapid range expansion of zebra mussels is most likely due to several factors. Veligers drift in currents and can be carried in water transported from one place to another via bilges, bait buckets and ballast. Adult mussels travel attached to trailers, boats, motor parts and equipment, as well as on vegetation clinging to any of these. The extent of the zebra mussel threat to New England's waterways isn't completely predictable because the chemical and physical properties of fresh water in the region differ somewhat from those of the Great Lakes. Nevertheless, zebra mussels have proven capable of tolerating a growing range of environmental conditions. A defensive approach to the threat is necessary. Interstate boaters and anglers can help protect water resources by observing several simple precautions when traveling between infested waters and uninfested waters. If you've been boating in Lake Champlain or in other freshwater bodies outside of New England within the previous 10 days and plan to launch locally, PLEASE...
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In the
natural systems they infest, zebra mussels disrupt food webs by consuming or
redistributing large volumes of phytoplankton (microscopic algae). Normally, the
phytoplankton is food for zooplankton (microscopic animals) that, in turn, nourish many
small fish. The filtering that occurs while zebra mussels are feeding makes water clearer
at the expense of altering the distribution, type and amount of plant life available at
the base of aquatic food webs. Although some fish and diving ducks prey upon zebra
mussels, no predator capable of controlling the mussels has been found. Zebra mussels tend
to concentrate toxic contaminants in their body tissues. These toxins may be passed on and
cause harm to the mussels predators.