Zebra Mussel Infestation

Anyone familiar with the Great Lakes has heard of Zebra Mussels. The little stripped mollusks have been on the steady incline since their introduction to the Great Lakes about two decades ago, and have caused great concern for scientists and sportsman alike. Being an invasive species that have practically no natural predators, their population has caused numerous problems with local species, sport fishing, and even lake dependent industry. Understanding the nature and reason behind these problem creatures is the beginning to their eradication.

The Zebra Mussel (Dreissena polymorpha) is a small mollusk that grows up to 2 inches wide, and lives for about 5 years. They are native to Russia, and previously to 1988 were never seen in North America. The leading theory as to how they arrived is that they were taken on in bilge water on European cargo ships, and discharged on the Canadian side of Lake St. Clair. Because a female Zebra Mussel can lie between 30,000 and a million eggs, their population exploded; and the environment has not responded well to their introduction.
The Zebra Mussel can filter up to a quart of water a day and with their numbers, have changed entire ecosystems. A good indicator of a heavy infestation (aside from visual confirmation), is observing a body go from cloudy to clear in a relatively short amount of time; though clear water may benefit some plant growth and plant eating fish, this merely serves a minor positive in an overall bad situation. In addition to starving other aquatic creatures by filtering out all the nutrients in the water, they also are known to anchor themselves onto living creatures, occasionally hindering them to immobility.
Industry and Utilities have also felt the toll from Zebra Mussels. Ships, ports, and fisheries often find themselves under siege by the never ending hoards of Zebra Mussels clinging to hulls, docks, nets, pipes, etc. Industry dependent on a constant flow of fresh water from the great lakes often find it necessary to remove masses of them from inlet pipes in order to prevent restricting the flow of water. This is particularly hazardous to nuclear power plants, which depend on the cool lake water to keep the reactors from overheating.
Current attempts to curb the Zebra Mussels ever increasing populations have overall been ineffective. Tough there a few animals that have begun feeding on them (perch, catfish, sunfish, and a few others) they still are pretty much safe from predators. Chemicals such as chlorine have been effective, but unfortunately it pretty much kills everything, including the environment that we are trying to preserve, so its use has been limited. Until a more effective means of removing them are discovered, the best we can do is brace for even more of them.
Anthony Antonelli
http://www.nationalatlas.gov/articles/biology/a_zm.html
http://www.glsc.usgs.gov/

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2 responses

  1. One of my friends lives on a lake in southern MI and the lake is filled with zebra muscles. What can boaters do to prevent spreading the muscles? Such as checking boats before placing in water or washing them off before entering another lake? It just seems that more actions can be taken by communities and boaters to prevent further spread.

    ~Gretchen Rambadt

  2. My family has a house on the south arm of Lake Charlevoix in the northern part of the lower peninsula. There are tons of Zebra Muscles in the water. There seems to be more and more every year. They are very annoying and cut up your feet and are also bad for the ecosystem. I have previously written the Governor with my concern about invasive species in the Great Lakes, unfortunately I have only ever received the standard letter, thanking me for my concern.
    Austin Wertheimer

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