Invasion of the Zebra Mussels Essay

This essay has a total of 746 words and 4 pages.

Invasion of the Zebra Mussels



Invasion of the Zebra Mussels

There has been an incursion into the sovereign territory of the United States of America.
The Zebra mussel, an animal much akin to the clam, has colonized nearly every hard surface
in the Great Lakes area, and many rivers and streams attached to them. These invaders
arrived on ships from England, pumped out through the ballast. Zebra mussels are from a
different environment (England), thus they are classified as an exotic species. These
pesky animals threaten the entire Great Lakes ecosystem.

The invasion has created many problems for the local ecosystem. First of all, Zebra
mussels take the food for which native species already compete. Each mussel consumes about
a liter of different types of plankton. Small fish lose their food, and their numbers
dwindle. Big fish no longer have small fish to eat, and the entire food chain is
disrupted. Now that the natives don’t have enough food to go around, mortality rates are
going up and they are starting to die out. Another problem they’ve created is clogging on
industrial units. They reproduce en mass and attach themselves to anything they find,
including docks, boat ramps, and waste pipes. All the industries in the area now have to
worry about scraping these mini-invaders off. Yet another problem they’ve created is
contaminated drinking water. The intake pipes in Lake Michigan and elsewhere are covered
with mussels. Without being removed, they contaminate water and move on to clog up city
pipes. Still another problem is their colonization of rock reefs. With the mussels being
several inches deep in places, their waste is poisoning the area and fish that would
normally lay their eggs there must look elsewhere for nesting areas. Now natality is down
and mortality is up. A final problem they cause is damage to property. By latching onto
boats and other floating objects, they can and will damage them. They cause innumerable
problems, so now the question has become one of prevention and removal.

Several methods are being used to attempt to prevent the mussels from establishing
themselves, and to try to reverse the problem. One method being tried is protective
coatings on surfaces, such as paints containing TBT or copper have been tried. The problem
with this is the paints often erode aluminum and other materials, and some are even
illegal. Another method is heat. Zebra mussels are extremely sensitive to heat. They have
a 100% mortality rate after 5 hours at 90°, or after only 15 minutes at 104°. The problem
with this method is simply the fact that it is hard to apply. A final approach that has
been tried is the application of chlorine. The chlorine works well in wells and bilges,
but cannot be applied to lakes or streams due to its nature of being toxic to living
things. The mussel’s history in England is no help, for they have native predators there,
diving ducks for example, that help control them. Populations of ducks like these European
ducks in the Great Lakes are small, so our situation is quite different from theirs. Some
method must be developed to combat these invaders; they are out competing all the native
species. They are such a good competitor in the Great Lakes community because they have no
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