Too much mussel: Mollusk explosion could do great harm to Lake Michigan sport-fishing industry

Below the steel blue waters of Lake Michigan, a giant sucking sound is transforming the world's sixth largest lake in ways that scientists never thought possible.

An estimated 330 trillion quagga mussels carpet vast areas of Lake Michigan's underbelly. The foreign mollusks literally are sucking the aquatic life out of the water and depositing it on the lake bottom, according to new scientific data.

"It's unbelievable, the changes that are happening," said Gary Fahnenstiel, a senior ecologist at the National Oceanic and Atmospheric Administration's Lake Michigan Field State in Muskegon. "The quagga mussel population has exploded and is taking over the lake bottom."

Quagga mussels are the slightly larger and far more disruptive cousins of zebra mussels. The filter-feeders have been linked to increased algae blooms that have fouled Great Lakes beaches and botulism outbreaks that have claimed more than 70,000 fish-eating birds and countless fish.

The dime-sized mollusks that ocean freighters unintentionally imported to North America in the late 1980s are turning Lake Michigan and its twin -- Lake Huron -- into biological mirror images of Lake Superior.

That's good news for people who enjoy clear water. But it is potentially disastrous for the Lake Michigan's billion-dollar sport fishery. The reason: Quagga mussels hog vast quantities of tiny plankton and other organisms that are the foundation of the lake's fish food chain.

Some fish species have resorted to eating quagga mussels just to survive, a situation analogous to humans dining on pretzels instead of steak or fish.

Each quagga mussel can filter up to a liter of water through its tiny body every day. The hundreds of trillions of quaggas in Lake Michigan have derailed the natural distribution of carbon and plankton -- the fuel that powers the lake's entire ecosystem.

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