The bloom in the western waters of the lake could eventually reduce populations of walleye, a favorite of fishermen, and increase the number of invasive zebra and quagga mussels, they said.
While the eastern end of Lake Erie may look clean and clear, "it's an optical illusion," Tom Marks, New York director of the Great Lakes Sport Fishing Council, told the Buffalo (N.Y.) News Tuesday.
From the lake's Michigan shore, the bloom extends eastward to the area north of Cleveland, the National Oceanic and Atmospheric Administration reported last month.
Two feet thick in places, the bloom resulted in beach advisories throughout the lake's western basin, and toxins in the algae tested at 1,000 times the World Health Organization's standards for drinking water, the newspaper said.
Environmentalists say the algae bloom is larger than any the lake experienced in the 1960s, when algae was so widespread experts declared the lake "dead."