The Great Lakes, which contain about a fifth of the world’s fresh water, were landlocked until the Erie Canal opened in 1825, allowing in predators like the sea lamprey that sucks the blood from native lake trout.
More than 180 other invasive species made their way to the Great Lakes through canals and the St. Lawrence Seaway including alewives, which eat lake trout eggs and baby trout, and zebra mussels, which clog pipes and help spread bird-killing botulism. Invasive species cost the Great Lakes region more than $100 million a year. Trillions of quagga mussels carpet much of the bottom of Lake Michigan. Like zebra mussels, quagga mussels eat plankton, taking food from native fish, and populations of salmon, whitefish and native mussels have plummeted.
The problem is poised to get worse. Much worse. Silver and bighead carp, two types of Asian carp, are making their way up the Illinois River toward Lake Michigan. Asian carp can grow up to 4 feet long and 100 pounds and eat the food native fish depend on.
They could make up as much as a third of the weight of Lake Erie’s fish if they establish themselves in the Great Lakes. The fish could also spread to rivers and streams in Wisconsin, Michigan, Indiana and Canada from the Great Lakes. Click on the following sentence to access the full story.