Quaggas creating more of an algae mess

[Hamilton Reef]

Mussel beach: Quaggas creating more of an algae mess

http://www.mlive.com/news/chronicle/ind ... xml&coll=8

07/18/07 By Jeff Alexander jalexander@muskegonchronicle.com

The algae bloom that slimed miles of area beaches on Father's Day was a harbinger of bad things to come along the Lake Michigan coast -- all of which can be traced back to a foreign mussel species.

Forget about zebra mussels, they were so 1990s.

The culprit behind the June 17 algae bloom was the quagga mussel (pronounced KWA-guh) -- the bigger, stronger, more prolific cousin of the zebra mussel, experts said.

Quagga mussels have colonized vast areas of the bottoms of lakes Michigan, Huron, Erie and Ontario over the past few years, according to scientific data.

The mussels have dramatically increased water clarity. But the dime-sized mollusks are consuming phenomenal quantities of microscopic fish food and fueling algae blooms that have closed miles of Great Lakes beaches and killed 2,800 fish-eating birds last fall at Sleeping Bear Dunes National Lakeshore in northern Michigan.

"Quagga mussels are probably going to have a bigger ecological impact on Lake Michigan than alewives did," said Gary Fahnenstiel, a senior ecologist at the National Oceanic and Atmospheric Administration's Lake Michigan Field Station in Muskegon.

Alewife, an ocean species that invaded the Great Lakes in the early 1900s, hurt native fish species and often died in huge numbers in the 1960s, covering miles of Lake Michigan beaches with tons of stinky fish.

"Quagga mussels are restructuring the whole food web of Lake Michigan," Fahnenstiel said. "When it's all said and done, the impacts from quaggas are going to be huge."

The European mussels were imported to Lake Erie in 1989 via ocean-going freighter ballast water. Quaggas showed up in Lake Michigan around 2000, according to federal officials.

Commercial and sport anglers have expressed concern recently about quagga mussels because they make the water so clear it's harder to sneak up on fish, said Jim Dexter, Lake Michigan basin coordinator for the Michigan Department of Natural Resources.

Dexter said sport anglers are reporting another good year of salmon fishing on Lake Michigan. But he said DNR officials are concerned that quagga mussels could cause salmon to starve, just as the mussels did in Lake Huron.

"The number of quagga mussels have grown exponentially in Lake Michigan; it's pretty disturbing to see," Dexter said. "With the quaggas' biomass being so large and the mussels being found so much deeper, I think they could lead to some large scale effects."

The volume of quagga mussels in Lake Michigan tripled last year while the volume of prey fish in the lake decreased, according to NOAA data. The mussels are suspected of eliminating nearly all the diporeia, a freshwater shrimp, from Lake Michigan and Lake Huron.

Dexter said the only positive aspect of the quagga mussel invasion has been a dramatic increase in water clarity in Lake Michigan.

Quagga mussels are worse than zebra mussels because they attach to almost any surface and can live in the cold, deep areas of the Great Lakes where zebra mussels cannot survive. Unlike zebra mussels, which only colonized rocky areas and other hard surfaces, quaggas cling to sand, creating reefs of mussels on the lake bottom, Fahnenstiel said.

A type of algae called cladophora flourishes where quaggas are present, experts said. The mussels increase water clarity, which allows sunlight to penetrate deeper into the water and stimulate algae growth.

Quaggas also spit out phosphorus-rich feces that fertilize algae and provide the hard surfaces that cladophora clings to. The mussels basically allow cladophora to grow in areas where it wouldn't under natural conditions.

"With quaggas creating huge reefs of mussels in the Great Lakes, they are creating a much larger area for potential cladophora (algae) blooms," said Alan Steinman, director of Grand Valley State University's Annis Water Resources Institute in Muskegon.

Steinman said one of the major concerns associated with cladophora that washes ashore is that the algae can harbor potentially harmful bacteria, such as E. coli, as it decomposes on the beach.

Scientists at the University of Wisconsin have found elevated levels of E. coli in cladophora on numerous beaches in the Milwaukee area.

Elevated concentrations of E. coli were found in the water at Pere Marquette beach in Muskegon two days after the June 17 cladophora bloom. It is not known if the algae caused the elevated bacteria levels, which prompted health officials to close one of the area's cleanest beaches for a day.

Quagga mussels also have been linked to the massive bird die-offs on the shores of lakes Michigan, Huron, Ontario and Huron in recent years.

Harvey Bootsma, a research scientist at the University of Wisconsin-Milwaukee's Great Lakes Water Institute, said cladophora blooms suck the oxygen out of the water, which allows Type E botulism to flourish. The botulism bacteria is ingested by quagga mussels, which are immune to it, and passed onto fish and fish-eating birds.

Thousands of gobies, an exotic fish species also imported to the Great Lakes by ocean freighters, have died in Lake Erie and Lake Ontario after eating quaggas infected with Type E botulism. Thousands more fish-eating birds, including loons, mergansers and a few bald eagles, have died after eating gobies infected with Type E botulism, according to experts in Michigan, New York, Pennsylvania and Ontario.

Bootsma said preliminary research indicates that large bird die-offs from Type E botulism only occur in areas where there are large mats of cladophora. "I don't think you'll see bird die-offs if there are only small patches of cladophora," he said.

Swimming in a cladophora bloom is safe but experts recommend keeping children and pets out of algae that piles up on the shoreline. Bacteria lives longer in cladophora on the beach than it does in the water or sand, Bootsma said.

Fahnenstiel said West Michigan's sandy beaches probably won't support the enormous, thick mats of cladophora found in other Great Lakes coastal areas, such as Milwaukee and Sleeping Bear Dunes.

Still, Fahnenstiel said West Michigan residents will become familiar with quaggas as the mussels cause more algae blooms and cause changes in Lake Michigan fish populations.

"The quagga mussels are going to dwarf the effects that zebra mussels had on the Great Lakes ecosystem," Fahnenstiel said.

With 185 exotic species already in the Great Lakes and a new species arriving every few months, Steinman said it is difficult to predict what the future holds for the world's largest freshwater ecosystem.

"These (Great Lakes) food chains have developed over the past 10,000 years and we've had these massive changes develop over the past 50 years with the introduction of exotic species," Steinman said. "We don't know what all the consequences will be."

[Hamilton Reef]

The quagga mussels can become well established over more diverse habitats than the zebra mussels. This makes it very important to continue practice clean boating habits. We (all boaters sportfishers and recreational) are clearly the defense line as the direct link from Great Lakes to inland waters. VHS, mussles, Eurasian watermilfoil.... the list goes on and on with more challenges to come that we don't even know about yet.