Justin Murphy The Citizen

AUBURN — Three recent reasons for concern about the water at the northern end of Owasco Lake are likely interrelated, the Cayuga County Water Quality Management Agency concluded Thursday.

In a nutshell: the lake appears to have a growing population of Asian clams, an invasive species.

The clams consume green algae, thereby allowing competing blue-green algae to grow out of control. The blue-green algae contributes to a rise in the levels of phosphorous and other organic materials, creating white foam on top of the water.

All three issues — the algae, the clams and the foam — have generated a lot of phone calls recently from concerned residents, Environmental Health director Eileen O’Connor said.

It’s not clear whether the clams or the blue-green algae came first, or how the clams originally got into Owasco Lake.

“It’s a correlation, but I don’t think you can prove a causation,” Robert Brower of the Institute for the Application of Geospatial Technology said.

Asian clams have been in Seneca Lake since 1999 and have appeared in the last few years in Lake George, the Champlain Canal and the Erie Canal near Utica, county environmental engineer Bruce Natale said.

“They’ve been around, but they’ve just started to move around to new places recently,” Natale said.

The clams prefer water that is warm, shallow and clear, without too many weeds. Deauville Island at the north end of Owasco Lake fits that description well, Natale said.

Asian clams are hermaphroditic, meaning that one organism can reproduce on its own at a rate of 400 eggs a day, Natale said. The calcium they produce attracts zebra mussels, another invasive species.

The clams could be eliminated if the water temperature in the lake gets below 38 degrees for a period of time during the winter, Owasco Lake inspector Jessica Miles said. Without the clams, the blue-green algae and foam might go away as well.

O’Connor stressed that the foam on the lake is not from soap or laundry detergent and is not dangerous.
“Rich bodies of water with a lot of organic material will tend to foam,” she said.

The Water Quality Management Agency is coordinating a volunteer effort to determine the extent of the clam and algae problems. No clams have been reported in other lakes in the county, and the group urged residents not to transport their boats from Owasco Lake to other lakes in order to keep the clams from spreading.

Staff writer Justin Murphy can be reached at 282-2237 or justin.murphy@lee.net. Follow him on Twitter at CitizenMurphy.

How to report problems

• To report Asian clams or foam in Owasco Lake, call Owasco Lake inspector Jessica Miles at 252-4171, extension 120.

• To report blue-green algae, call the Cayuga County Department of Environmental Health at 253-1405.

Blue-green algae can cause health problems for people and animals. People should not use algae-infested water for drinking, bathing or swimming.