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Kraft, C., SEPTEMBER, 1994. Zebra Mussel Update #22, University of Wisconsin-Madison, Wisconsin Sea Grant Institute A Newsletter produced by the Wisconsin Sea Grant Institute Zebra Mussel Update #22Summer Sightings Zebra mussels made their first significant move into Wisconsin inland lakes this summer. Adult mussels were found in Elkhart Lake in Sheboygan County and Racine Quarry in Racine County; veligers were discovered in a plankton sample from Okauchee Lake in Waukesha County. Subsequent surveys failed to turn up adult mussels in Okauchee Lake. No veligers were detected in more than 100 plankton samples collected from 70 inland Wisconsin lakes, including Lake Winnebago. Zebra mussel densities in Green Bay plankton samples were greater than in previous years, reaching a high of 210,000 per cubic meter in a sample collected August 15. Substrate sampler densities peaked in southern Green Bay at 350,000 per square meter on July 26. Scientists collecting samples from Lakes Michigan and Superior indicated that veliger densities at both locations were similar to densities measured last year. This summer for the first time ever veligers showed up in samples collected from the Fox River, several miles above its confluence with Green Bay, Lake Michigan. A moderate density of veligers (1,500 per cubic meter) was collected in a plankton tow south of the De Pere Dam. A small lock connects this area with infested waters downstream. Reports of cooling system intake blockages along the Milwaukee River also indicate that zebra mussels have successfully colonized this river several miles upstream from Lake Michigan. Zebra mussel observers reported relatively low numbers throughout the summer along the Wisconsin portion of the Mississippi River. ID: 199409-1. New Sightings in Wisconsin Zebra mussels were found for the first time in three inland Wisconsin lakes this summer. Moderate veliger densities were found in Okauchee Lake on a plankton sample taken July 22 by UW Sea Grant Advisory Services researchers. No additional veligers or adult mussels have been found in subsequent sampling of the 1,100-acre lake, including an August 10 diving survey conducted by Wisconsin Department of Natural Resources (WDNR) biologist Jim McNally and warden Gus Ernst. Okauchee Lake is upstream from the Oconomowoc River, which empties into the Rock River. The Elkhart Lake sighting was made July 31 by recreational diver Wyatt Wiehr, who found four mussels attached to a fishing rod recovered in 15 feet of water. Wiehr left the mussels with the Plymouth WDNR office for identification. Plankton samples and a WDNR dive survey turned up abundant veligers and adult mussels in the 286-acre lake. Wiehr made subsequent dives and found small numbers of mussels. On August 27 diver Bob Freedor collected zebra mussels at a depth of 17 feet in Racine Quarry, a 20-acre quarry located near the Root River a few miles from Lake Michigan. A follow-up investigation by WDNR biologist Steve Gallarneau turned up abundant mussels attached to a fishing pier along the quarry shoreline, and veligers were found in a plankton sample examined by Sea Grant personnel. Racine dive shop operator John Johnston of Reef Point Diving Center subsequently reported having observed zebra mussels in the quarry in 1993, perhaps as early as 1992. Although Racine Quarry has no public boat launch, Johnston said that he and other dive instructors from southeastern Wisconsin and northern Illinois regularly use the quarry for "check-out" dives and usually outnumber other water users. The quarry is located 40 yards from the Root River, a tributary to Lake Michigan. Anglers use a fishing pier and transport small boats to the quarry to catch stocked rainbow trout. The only prior inland zebra mussel sightings in Wisconsin were in the Mississippi River and a single sighting last September in Dairyland Reservoir on the Chippewa River. No additional mussels have been observed at the reservoir, and it appears unlikely that a population has become established there. De PERE - Veligers were found in samples collected in the Fox River in early August seven miles from where the river enters the bay of Green Bay. A moderate density of veligers (1,500 per cubic meter) was collected in a plankton tow upstream, south of the DePere Dam. A similar density of veligers (900 per cubic meter) was also found at the same time on the north, downstream side of the dam, near Voyageur Park. Previous samples collected at these locations have not contained veligers. Four paper mills currently use water from the Fox River between the DePere Dam and its confluence with the bay of Green Bay. ID: 199409-2. New Sightings Elsewhere BRAIDWOOD, Ill. - Zebra mussels have been found in the cooling pond for the Braidwood power plant, according to Commonwealth Edison Power Company environmental scientist Rich Monzingo. This power plant draws water from the Kankakee River, which, to date, has not contained zebra mussels. Samples collected and analyzed by Commonwealth Edison personnel have not detected any zebra mussels in river intake water, according to Monzingo. He attributed the mussels' presence in the cooling pond to overland transport by recreational boaters. Monzingo said that most of the 16 Commonwealth Edison power plants in Illinois are infested with zebra mussels. The exceptions include the Byron Station, which draws water from the Rock River, and the Sangchris plant, which is located near Springfield, Illinois. "There have been unconfirmed reports of mussels at Sangchris," Monzingo said. Surveys conducted this summer should help confirm these reports, he added. All Commonwealth Edison plants are using thermal treatment to control mussels, according to Monzingo. Along with the facilities mentioned above, the utility company has facilities on Lake Michigan, the Illinois River and the Mississippi River. BEAVER ISLAND, Mich. - Zebra mussels were found in July at two locations in the harbor of St. James, a village located at the north end of this large offshore island in northern Lake Michigan, according to diving consultant Daniel Hendrix. JACKSON, Mich. - Adult zebra mussels were found for the first time in six new Michigan lakes this summer, according to Paul Marangelo, a Sea Grant-funded University of Michigan graduate student sampling inland Michigan lakes. The lakes are Devils Lake (Lenawee County), Vinyard and Clark lakes (Jackson County), Silver Lake (Oakland County), and Portage and Whitmore lakes, (Washtenaw County). Veligers were also found for the first time in three additional inland lakes - Kent, Sylvan and Orchard lakes (Oakland County). Following an anonymous tip, Marangelo made the Vinyard Lake sighting in mid-June. Numerous mussels were found attached to strands of Eurasian water milfoil. Orchard Lake receives water from Cass Lake, where "Dreissena" veligers were found for the first time during the summer of 1993. This summer Marangelo also re-sampled five lakes in the northern part of Michigan's lower peninsula, known as the "Tip of the Mitt" region. Only a single veliger was found this July in Burt Lake, one of four lakes in which veligers were found during the summer of 1993. No adult mussels have ever been found in these lakes. PICKAWAY COUNTY, Ohio - Zebra mussels were sighted in Circleville Twin Quarries on May 21, according to Ohio Sea Grant Extension Specialist Fred Snyder. Circleville Twin Quarries is a popular scuba diving location in the south-central part of the state. Zebra mussels have also been found in Hargus Lake, located in Pickaway County. MOUNT MORRIS, N.Y. - In the fall of 1991, "an incredibly enormous number of zebra mussel veligers" were found in Conesus Lake by SUNY-Brockport graduate students, according to information provided by the Livingston County Department of Public Health. Densities as great as 30,000 per cubic meter were found during a three-week period that summer, later verified by New York Sea Grant's Dave MacNeill. However, no settled zebra mussels were spotted in the lake until this summer. In early July a single mussel was found attached to a Unionid clam, and another was found in early September, according to Ralph Van Houten, county environmental health director. Van Houten said that following the veliger report several years ago, small water utility operators and hundreds of homeowners with potable water intakes were warned that zebra mussels posed an immediate threat to lake water intake lines. Despite the urgent warnings, Van Houten said, "We still don't see an impact." The situation is similar to that of several inland Michigan and Wisconsin lakes where veligers have been collected but adult mussels have not yet been found. NORTHBROOK, Ill. - Zebra mussels have been found in the irrigation ponds of two golf courses on Chicago's north side, according to Ken Gardiner of the Northbrook Water Utility. This water utility provides chlorine-treated water from "Dreissena"-infested Lake Michigan directly to irrigation ponds at the Green Acres Country Club and the Lake Shore Country Club. According to Gardiner, fairly large numbers of adult zebra mussels have been found in one irrigation pond at Green Acres; smaller mussels were found at the Lake Shore Country Club. The water utility has been chlorinating raw water entering the plant's Lake Michigan intake for nearly two years. The chlorination seemed to be effective - no adult mussels have been observed at the Northbrook water treatment plant, located 3.5 miles from the water intake. However, Gardiner noted that some veligers must have survived the intake chlorination in order to colonize the golf course ponds, which are located as far as three-and-a-half miles from the water intake. Golf course workers said the mussels haven't caused irrigation system problems, Gardiner said. ID: 199409-3. Invasion Progress Report SUPERIOR, Wis. - Despite the presence of a few large zebra mussels in Superior harbor, UW-Superior biologist Mary Balcer said that few newly settled mussels or veligers have turned up there. She characterized the situation as "nothing like we would expect" from a self-sustaining population. Balcer's Sea Grant-supported research this summer included analyzing plankton and substrate samples taken from Superior harbor, and conducting zebra mussel growth experiments to examine the impact of low calcium levels on zebra mussel growth. MILWAUKEE, Wis. - Zebra mussel veliger numbers varied at Wisconsin Electric Power Company power plants this summer, according to technician John Babinec. Weekly veliger sampling was conducted at three of five Lake Michigan facilities. The Pleasant Prairie power plant averaged 8,000 veligers per cubic meter, up from an average of 5,000 last summer. The Point Beach power plant averaged 8,000 per cubic meter, about the same as last year, and veliger densities at the Oak Creek facility were down from 3,400 last year to 2,900 this year. Season highs were observed August 10 at Pleasant Prairie (55,000 per cubic meter) and Point Beach (34,000). Veliger densities at Oak Creek never exceeded 10,000 per cubic meter. Babinec said divers cleaned up a massive infestation in the pumphouse forebay at the Oak Creek power plant this summer. This area of the plant intake system currently must be treated manually. The mussels are under control, but continue to be a nuisance, Babinec said. OSWEGO, N.Y. - Quagga mussels (Dreissena bugensis) are beginning to displace zebra mussels in western Lake Ontario at depths greater than 25 meters, according to National Biological Survey fishery biologist Randy Owens. Owens said between 50 to 100 pounds of quagga mussels were collected this summer in 10-minute tows using a bottom trawl. By comparison, only a half dozen mussels were found in 1991 using the same collection method. Owens said quagga mussels are abundant at depths up to 55 meters in the western part of the lake. They have not yet completely colonized the eastern end. HAVANA, Ill. - Zebra mussel numbers dropped dramatically this summer at an Illinois River location near Grafton, Ill., where zebra mussels carpeted the bottom in 1993, according to biologist Doug Blodgett of the Illinois Natural History Survey (INHS). High densities of 61,000 per square meter in 1993 near Grafton dropped to 4,000 per square meter in similar 1994 surveys. Blodgett said that extremely high water conditions in 1993 closed the river to commercial barge traffic and could have produced unusually favorable settlement conditions. Based on surveys here and at other Illinois River locations, Blodgett said he believes that river populations are "very variable." Other surveys this summer also indicate that Mississippi River zebra mussel populations and Unionid mussel infestation rates remain much lower than in the Illinois River. Blodgett reported finding no zebra mussels in a mussel survey on the Mississippi River in Pool 25, several miles upstream from its confluence with the Illinois River. Farther upstream near Moline, INHS divers surveyed native Unionid mussel beds near Campbell Island in Pool 15 on Sept. 14 and 15. Of 1,000 native mussels examined, on average at least one zebra mussel was attached to every Unionid found, according to INHS biologist Helen Kitchel. A zebra mussel density of 48 zebra mussels per square meter was estimated in another mid-August INHS survey in Pool 15. ID: 199409-4. The Thick Water Diet FRIDAY HARBOR, Wash. - Biologists generally observe that "cold-blooded" invertebrates, such as zebra mussels, feed more slowly at low temperatures. They usually attribute this to the fact that physiological processes slow down at lower temperatures. But slower feeding by planktonic invertebrate larvae at low temperatures may result from changes in water viscosity rather than temperature, according to a July 1 report in "Science" by University of Washington zoologist Robert Podolsky. Podolsky observed that feeding by sand dollar larvae, which are slightly larger than zebra mussel veligers, declined just as much due to changes in water viscosity at low temperatures as to physiological effects of low temperature. Simply stated: It's hard to strain food out of water when it's thick as molasses. "The biological effects of viscosity may prove to be especially important in freshwater systems," Podolsky said. ID: 199409-5. Hudson River Impacts MILLBROOK, N.Y. - The first reports of substantially reduced phytoplankton biomass in a river system infested by zebra mussels were given in two papers presented at this summer's annual meeting of the Ecological Society of America. Institute of Ecosystem Studies (IES) biologist Nina Cole reported that an 85 percent decrease in summertime phytoplankton biomass in the Hudson River has coincided with the invasion and establishment of zebra mussels. Models predict that the physical environment in large rivers makes phytoplankton particularly sensitive to benthic grazers such as zebra mussels, Cole said. In a companion presentation, IES biologist Michael Pace reported that zooplankton such as tintinnid protozoans, rotifers, copepod nauplii and the cladoceran "Bosmina longirostris" have declined along with the phytoplankton. Pace and Caraco's observations include several years of phytoplankton and zooplankton collections prior to the Hudson River zebra mussel invasion. ID: 199409-6. "Keep America Beautiful"? MINNEAPOLIS, Minn. - Billboards were used here this summer to educate Minnesotans about aquatic nuisance species, including zebra mussels. The billboards were in various Twin Cities locations May 1 through August 31. The Minnesota Department of Natural Resources and the U.S. Fish and Wildlife Service funded the project. In another Minnesota effort, the National Park Service operated a free rinse station at four boat landings near the St. Croix National Scenic Riverway this summer. Rinse station staff provided boaters with zebra mussel information and showed them how to inspect their boats. In July alone, 321 boats were decontaminated at the stations. ID: 199409-7. Mussels Turn Up the Heat on Milwaukee Politicians MILWAUKEE, Wis. - Zebra mussel infestations caused problems in two downtown Milwaukee building cooling systems late this summer. The first problem turned up in a system that uses Milwaukee River water to cool three municipal buildings, including Milwaukee City Hall. Following summer-long problems with an overheating condenser, a Labor Day inspection revealed that the cooling system was seriously fouled with zebra mussels, according to Jim Farley of Cooling Services, Inc., of Waukesha, Wis. During the Labor Day clean-out, up to eight inches of zebra mussels were found in an intake area, and one of four water pumps had to be replaced due to mussel-caused damage. The system normally operates year-round and uses four pumps to move 2,500 gallons of water per minute to the three municipal buildings, which house 3,000 employees. A similar problem developed at the 725 N. Water Street building when several cooling system condensers became clogged with zebra mussels, according to building manager Dennis Papp. The cooling system for the 16-story Water Street building also draws water directly from the Milwaukee River, which is several miles upstream from Lake Michigan. Papp had noticed that the condenser pressure was high earlier in the summer, but didn't know why until mussels were found throughout the condenser. A water intake chamber was also full of zebra mussels. The system cannot easily be chlorinated, and Papp is exploring other alternatives. Many older buildings in urban areas use raw surface water in their cooling systems, making them susceptible to similar zebra mussel clogging. ID: 199409-8. Upcoming International Conference Organizers of the Fifth International Zebra Mussel Conference have announced a call for papers. The conference will be held Feb. 21-24, 1995, at the Westin Harbour Castle Hotel in Toronto, Ont. The conference will include a review session with invited papers, workshops, a trade show and contributed papers on a variety of topics related to zebra mussels and other aquatic nuisance organisms. Authors are invited to submit a one-page abstract for verbal or poster presentations by Sep. 30, 1994, to Renata Claudi, Ontario Hydro, 700 University Ave., H16-B19, Toronto, Ont., Canada M5G-1X6. Conference registration is $320 Canadian ($295 U.S.) before December 16. For conference information contact Elizabeth Muckle-Jeffs at (800) 868-8776. ID: 199409-9. There's No Place Like Home MONTREAL, Que. - There has been speculation about the ability of zebra mussels to enhance populations of other benthic animals by providing pseudofeces as a food source and offering a safe haven as interstitial habitat. McGill University biologist Anthony Ricciardi recently reported that zebra mussels do, in fact, provide a new home for some chironomid flies, also known as non-biting midges (or gnats to most people). Ricciardi observed large numbers of chironomid larvae living inside zebra and quagga mussels in the Soulanges Canal area of the Upper St. Lawrence River, southwest of the Isle de Montr al. These larvae, of the genus "Paratanytarsus," appeared to cause no damage to their host, which biologists call a commensal relationship. The midges most commonly inhabited the mantle cavity near the inhalant siphon. The midge larvae Ricciardi observed may belong to a species that has been reported to foul water supply systems and has been found blocking the filters of aquaculture circulation equipment in New Brunswick. Ricciardi's results will appear in the September issue of the "Canadian Journal of Zoology.". ID: 199409-10. Exotic Locale UW Sea Grant-funded aquatic ecologist Dianna K. Padilla presented a symposium paper in late September at the Seventh Zoological Conference on the Preservation, Investigation and Usage of Biological Diversity of the Belarussian Animal World. The conference was held at the Institute of Zoology of Belarussian Academy of Science in Minsk, Belarus. Her paper was titled "Invasion of exotic aquatic organisms: Whether the process could be predicted and controlled?" Padilla was one of three Americans participating in the international conference. ID: 199409-11. Conference Proceedings Still Available Wisconsin Sea Grant is still accepting orders for a two-volume set containing 50 of the key research papers presented at the Fourth International Zebra Mussel Conference held last March, in Madison, Wis. Each set costs U.S. $25 plus shipping ($3 within the United States; $5 to Canada.) To order, send a written request indicating the number of sets you would like to receive along with your name and shipping address to: Proceedings, UW Sea Grant Institute, 1800 University Avenue, Madison, WI 53705-4094, or fax to (608) 263-2063. For more information, contact Liz Hanson at the UW-Sea Grant Institute's Advisory Services Office, phone (608) 265-5109. ID: 199409-12. Kraft Family Robinson Now that zebra mussels have focussed my attention on exotic invaders, other odd exotic plants and animals seem to keep cropping up in my life. My family inherited a green tree frog from Florida that hitched a ride on a potted plant purchased from a Green Bay florist - solid evidence that hitchhikers make good invaders. Another example turned up this spring when a world record "piranha" was caught in Lake Columbia, a power plant cooling pond in central Wisconsin. The fish turned out to be a "pacu," a type of South American fish superficially similar and taxonomically related to the piranha. WDNR fish researcher John Lyons said he believes the fish was probably released by an aquarium owner. Lyons said that on two occasions he has seen a large "Oscar," a bass-like Cichlid fish, caught by anglers in Wisconsin waters. So what's the point of all this? Well, while reading "Swiss Family Robinson" with my kids this summer I kept reminding them that no real island could possibly contain all of the kangaroos, lions, penguins, salmon, onagers, monkeys, boa constrictors and other assorted animals that keep the heroes on their toes (though the book does conspicuously lack Disney-fabricated pirates). But with Florida tree frogs and pacus in Wisconsin, maybe I should reconsider my fatherly wisdom. ID: 199409-13. Keywords: Industry, Inland_lakes/rivers, Population_dynamics |