New Sightings in Wisconsin

From June 5, 1992 (update #13)

RACINE - Thousands of tiny (2 mm) zebra mussels were found in mid-May on rocks retrieved by divers inspecting water intake structures of the Racine Water Utility, according to Plant Superintendent Herb Schmidt. The divers at first noted only a few larger zebra mussels on the rocks, but upon closer inspection Schmidt observed thousands of tiny mussels clustered near a few larger mussels on the underside of the rock.

SHEBOYGAN - Zebra mussels were found several times during the past few months in units of the Edgewater Generating Station operated by Wisconsin Power & Light (WP&L), according to Production Engineer Dan Everson. In January, several small mussels (under 5 mm) were found in an oil cooler on four boiler feed pumps in WP&L Unit 4, Everson said. On April 25, 40 to 50 small mussels (3-9 mm) were found in the main condenser of WP&L's Unit 5. Two days later, a small colony of larger mussels (about 100 mussels 10-24 mm long) was found on the cover of a generator hydrogen cooler in WP&L Unit 4. The utility plans to treat Units 3 and 4 of the Edgewater Generating Station with hot water. WP&L will treat Unit 5 with chemicals, Everson said, but the specific treatment has not been determined.

MANITOWOC - Thousands of zebra mussels were found during a May 22 maintenance inspection of a condenser at a power plant and the raw water shore well of a water treatment facility operated by Manitowoc Public Utilities (MPU), according to Water System Manager Nilaksh Kothari. The condenser had been inspected last in February 1991, Kothari said. The city-owned power and water treatment plants share dual water intakes. These provide enough intake capacity so that both facilities can operate using one intake while the other is treated for zebra mussels, according to Kothari. MPU has received WDNR approval for a one-time chlorine treatment of the MPU shore well. MPU also is the first utility to request and receive WDNR approval to dispose of mussels killed by chemical treatment.

TWO RIVERS - Divers from Seaview Diving Co. found many large zebra mussels (up to 25 mm long) in the seal well and discharge flume of the Point Beach Nuclear Power Plant during a routine maintenance inspection April 27, according to Wisconsin Electric Power Company Senior Environmental Scientist Dave Michaud. The plant's forebay and pumphouse areas, including both sides of the traveling water screens, were free of mussels, however.

KEWAUNEE - In late January, a single mid-size (10 mm) zebra mussel was found attached to the Green Bay Water Utility intake pipe wall near the wet well on shore, according to utility manager Bill Nabak. The mussel was found by employees of Commercial Diving Services, Inc., who were installing a chemical feed system to control zebra mussels at the facility.

GREEN BAY - No zebra mussels have been found in shoreline surveys conducted this spring by Zebra Mussel Watch Assistant Coordinator Jory Jonas at locations where mussels were found last summer and fall. Winter ice conditions are probably responsible for their absence in nearshore regions. One finding of zebra mussels in extreme southern Green Bay was reported by Robert Thiry, Triton Marine Enterprises, who found about two dozen medium to large (8-22 mm) zebra mussels attached to the hull of a work barge on May 30. The barge had been out of the water for the winter prior to being placed in the bay in early May. Since the barge was in contact with bay sediments while in use, the mussels only had to travel a short distance to attach to the hull.

ID: 19920605-2.

The Zebra Mussel Update was a 4- to 8-page quarterly national newsletter published by the University of Wisconsin Sea Grant Institute from May 1990 through May 1997. The ZMU documented the spread of the zebra mussel -- an exotic nuisance mussel -- through North America's freshwater environments, especially the Great Lakes, and on efforts to control it.