Friday, November 10, 2017

Zebra and quagga mussels

When they picked up cargo further up the Great Lakes system, that ballast water was drained. This is probably how zebra mussels and quagga mussels found their way from the Caspian Sea into the very hospitable environment of the Great Lakes and the St. Lawrence River. These tiny mollusks have destroyed many of the fisheries of the Great Lakes, and clog up water intakes of cities and towns along the shores. To make matters worse these mussels exited the Great Lakes “back door”, a canal in Chicago that connects to the Mississippi River watershed. Zebra and quagga mussels now damage that mighty river system and have even spread to the giant western reservoirs of Lake Powell and Lake Mead.

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