Zebra Mussels – Their Effect on the Great Lakes
This Invasive Mollusk Can Alter the Environment and Affect Industry
Jul 21, 2009
Zebra mussels,(Dreissena polymorpha), named for their distinctive stripes, are a small clam- like freshwater mollusk indigenous to Europe and the eastern Soviet Union. They were first identified in the United States in 1988 and since then have spread to all the Great Lakes, and waterways in many states.
How Did Zebra Mussels Reach the United States?
Zebra mussels were first discovered in Lake St. Clair near Detroit, MI and from there they spread to the Great Lakes. But how did they reach Lake St. Clair, an inland lake, from their home in Russia near the Caspian Sea? Doug Jensen, an aquatic invasive species specialist asserts, “Canals built during the late 1700s allowed the mussel to spread throughout eastern Europe.” He goes on to explain that more canals were built in the 1800s which made shipping easier but also opened the door for zebra mussels to increase their range. Jensen says, “By 1830 the mussels had covered much of Europe and Britain.
But how did the mussels get from Europe to the United States? The answer is simple. They hitched a ride in ballast water discharged from a transoceanic vessel into Lake St. Clair. The St Lawrence Seaway, a series of manmade locks and canals in the St. Lawrence River between Ontario and Montreal, connected freshwater ports on the Great Lakes to the global shipping network. In doing so it mirrored the canal system that made possible the spread of zebra mussels in the 1700s and 1800s in Europe.
Why are Zebra Mussels a Threat ?
Zebra mussels are causing an estimated $400 million in damage to the Great Lakes annually.
- Economic impact of zebra mussels: The Great Lakes Science Center estimates the potential economic impact to be in the billions of dollars over the next ten years to U.S. and Canadian water users within the Great Lakes region alone. According to his July 21, 2009 article in The Buffalo News, Brian Meyer reports that The city of Buffalo, New York, located on Lake Erie, may have to spend between $4 million to $5 million to haul away an eight foot mound of dead zebra mussels that has clogged the city’s water intake pipe.
- Ecological impact of zebra mussels: In his June 6, 2009 article on Sheyboyganpress.com, Jeff Alexander says, “Zebra and quagga mussels are literally sucking the aquatic life out of Lakes Michigan and Huron, causing whitefish and salmon to shrink and threatening a multi-billion dollar fishery. The mollusks took a $350 million bite out of Lake Erie’s tremendous walleye fishery over the course of a decade.”
Zebra Mussel Control
On the U.S. Geographical Survey website, zebra mussels are compared to roaches because of the almost impossible task of eradicating the two species. Despite scientific efforts to develop a species specific control agent, at present, there is no effective way to eradicate zebra mussels once they are established in a body of water.
Preventing Zebra Mussels
Although there is no effective way to destroy this biological plague, the U. S. Geographical Survey website concludes there are ways to prevent their spread, “Human activities have spread zebra mussels into many inland lakes and streams, usually through recreational boating, fishing, and diving practices. Simple steps such as draining live wells, cleaning vegetation off boat trailers, removing attached zebra mussels from boat hulls, and not dumping bait into lakes or rivers can prevent the spread of zebra mussels and other exotics into non-infested waters.”
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