Millions of mussels likely cause of Magothy River's clarity

In the 18 years that Paul Spadaro has lived on the Magothy River, this is the first time his kids are scared to go in the water.

"They were raised here and they're used to swimming in water where you couldn't see anything," said Mr. Spadaro, president of the Magothy River Association. "The water quality now is phenomenal. I've heard it described as gin clear."

The top suspect? Mussels, millions of them, which have attached themselves to ropes, boats and anything else manmade throughout the river.

The dark false mussel, Mytilopis leucophaeata, is native to the Chesapeake Bay, but residents along the river say they haven't...