Status Elsewhere

From June 28, 1990 (update #2)

SOUTHERN LAKE MICHIGAN - An unusual confirmed sighting of zebra mussels in an Indiana tributary to Lake Michigan was reported recently by Kevin Cummings of the Illinois Natural History Survey (INHS). Three sets of matching zebra mussel shells were collected in May 1988 in the Lake George Canal in Lake County, Ind., as part of an INHS sediment toxicity survey, cataloged with the fauna collection (INHS museum identification #9566) but only recently identified as zebra mussels. This find predates by a month the first reported discovery of zebra mussels in the Great Lakes in Lake St. Clair. The Lake George Canal is connected to the Indiana Harbor Ship Canal, which is a heavily used industrial waterway located among the refineries and steel mills of northwestern Indiana. How the zebra mussel shells got there is unknown. No sightings of live zebra mussels from southern Lake Michigan have been reported to date, though no further surveys of this particular area have been conducted.

NORTHERN LAKE HURON - More than 40 adult mussels were discovered June 14 on and around a steel bridge in the Thunder Bay River at Alpena, Mich., by a local diving instructor. Since then, many more have been found in the river and at several sites out in Thunder Bay itself - including one of the town's municipal water intakes. None of the infested surfaces was entirely covered with zebra mussels, however. The mussels range from less than a quarter-inch to more than one inch across, leading local Michigan Department of Natural Resources biologist James Johnson to conclude that the bay has been infested for at least two years. Johnson noted that this is the farthest north that the mussels have been spotted in Lake Huron, but he added that no one has really looked extensively along much of Michigan's coast.

SAGINAW BAY - Forty to 50 half-inch-long zebra mussels were found in May attached to a barge on the Saginaw River just a few miles upstream from Saginaw Bay near Bay City, Mich. The barge had been brought from Lake St. Clair to Saginaw Bay in October 1988 for dredging work last year. The barge sank last winter while moored at a Saginaw River marina and was refloated in May. Bay Metro Water Treatment Plant manager John DeKam said the city's water intake was inspected in early June by a diver, who found no zebra mussels - no news but good news for the accompanying boatload of news reporters and photographers (one TV station had even hired an underwater photographer to cover the event).

LAKE ERIE - Small numbers of veligers were found in the waters of the western basin of Lake Erie by mid-June by Ontario Ministry of Natural Resources personnel. This appearance corresponds to the timing of their first seasonal appearance in June 1989 but several weeks later than their first seasonal appearance in May 1988. Cool and windy weather has delayed the warm-up of Great Lakes waters and apparently pushed back the start of the season for zebra mussel growth and reproduction. Howard Riessen, professor of biology at the State College of New York at Buffalo, reported finding no veligers in the eastern basin of Lake Erie in early June this year. Dave Garton, professor of zoology at Ohio State University, observed during the summer of 1989 that small numbers of zebra mussels in the western basin of Lake Erie began spawning in June, with a steady increase in spawning until mid-August. This spawning period also corresponded to the period during which larval mussels first began settling on hard substrates. Based on these observations, colonization of new areas by zebra mussels is likely to begin soon. The next two months should be crucial to understanding the potential rate of expansion of zebra mussels into new areas.

ID: 19900628-3.

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.