Where did they come from ?
While no one can say with certainty, it is believed the pests were most likely introduced into the Great Lakes in the early 1980’s by a freighter emptying ballast tanks of water sourced from the Dneiper River Drainage of the Ukraine, or the Black or Caspian Sea Drainages. These are the regions and waterways that were historically the native homes for these pests.
Since this unfortunate accident, Congress has worked in a half-hearted manner to outlaw the practice of ballast water discharge and as of this writing they haven’t got it quite right yet. They were on the verge of lumping in domestic U.S. pleasure craft with the real offenders to make it illegal for pleasure boaters to discharge any water at all into U.S. waters, be it grey water, engine cooling water, or the products of deck hose downs. In other words, the lawmakers were very close to making the American public pay the price for their own incompetent oversight of a problem that surfaced twenty-five years ago.
Once established in the Great Lakes, it didn’t take very long at all for the creatures to infest nearly all of the major river drainages of the Eastern United States.
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Keeping in mind that the young of these creatures drift downstream on the currents, one may observe the map above and wonder how the mussels managed to leap-frog land masses and to apparently migrate upstream in many cases.
The facts of the matter are that they could not and did not do any such thing. In order to bridge such hurdles they had to have help. And that help was provided unwittingly, in most cases, by the transportation of mussel infested boats from one water body to another. And as the spread of these nasty things continues today, that is still the most common means of invasion of non-infected waters. |
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Mussel encrustation on propeller |
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