The king of all invaders

[Spiel]

The king of all invaders

 

April 09, 2008

Jeff Alexander / The Muskegon Chronicle

 

Chronicle file photo / Zebra mussels, above and quagga mussels have been called by some scientists the most harmful of all exotic species imported into the Great Lakes.

 

Scientists say foreign mussels' damage make it the worst of all Great Lakes' exotic species

 

Two decades after zebra mussels were discovered in the Great Lakes, some scientists are calling the foreign mollusks the most harmful exotic species ever to invade the world's largest freshwater ecosystem.

 

Several prominent researchers contend dreissenid mussels -- zebra and quagga mussels -- have caused more profound changes in the lakes than sea lamprey, which decimated lake trout and other native fish species in the mid-1900s.

 

"In terms of the whole food web, I don't think there's any question that zebra and quagga mussels have had the largest impact on the biological communities of the Great Lakes," said Tom Nalepa, a research biologist at the federal government's Great Lakes Environmental Research Laboratory in Ann Arbor.

 

Sea lamprey only affected fish at the top of the food chain. Zebra and quagga mussels have caused profound changes at all levels of the food chain in every Great Lake except Superior, Nalepa said.

 

David Jude, a research scientist at the University of Michigan, said sea lamprey caused more harm to Great Lakes fish than any other exotic species. Jude said sea lamprey would have eliminated lake trout from the lakes, and possibly other fish species, if the federal government didn't spend $15 million annually to kill the eel-like invaders.

 

In terms of overall impact on the lakes' ecosystems, Jude said dreissenid mussels are the king of change.

 

"I think the sea lamprey wreaked the most havoc on fish, since they drove lake trout to extinction in four of the five Great Lakes," Jude said. "But on any other account you wish to use, dreissenids win."

 

 

Chronicle file photo / Zebra mussels, left and quagga mussels were imported from Europe in the ballast of freighters.

 

 

Imported from Europe in the ballast water of transcontinental freighters, dreissenid mussels have caused a myriad of profound changes. Zebra and quagga mussels have:

 

- Clogged water intakes at power plants and municipal water treatment facilities, adding about $2 billion to the cost of producing electricity and clean drinking water.

 

- Dramatically increased water clarity, but at the expense of algae and other plankton. The mussels hog plankton, which comprises the base of a food chain that supports most aquatic life in the lakes;

 

Contributed to a precipitous decline in prey fish, which has caused larger predatory fish -- whitefish and salmon -- to shrink;

 

- Fueled algae blooms that have fouled beaches, killed countless fish and more than 70,000 fish-eating birds, including bald eagles and common loons;

 

- Spawned toxic algae blooms that cause taste and odor problems in drinking water and pose potential health threats to humans, fish and wildlife. Toxic algae blooms have surfaced in parts of lakes Erie and Huron and on inland lakes from Michigan to New York, including Muskegon and Bear lakes.

 

In recent years, quagga mussels have replaced zebra mussels across much of the Great Lakes. Unlike zebra mussels, which prefer warmer water and hard surfaces, quaggas can live on hard or soft surfaces and in the frigid depths of the lakes.

 

"Quagga mussels are probably the most ecologically significant perturbation that has ever been documented in Lake Michigan," said Gary Fahnenstiel, senior ecologist at the Great Lakes Environmental Research Laboratory's Lake Michigan Field Station in Muskegon.

 

Because zebra and quagga mussels occupy the middle of the Great Lakes food chain, they affect species above and below them, Fahnenstiel said. "They've totally altered the system," he said.

 

The mussels are just two of 185 exotic species in the Great Lakes. About 120 of those species were imported by ocean ships that discharged ballast water from foreign ports into the lakes, according to government data.

 

After zebra mussels shut down the water treatment plant in the city of Monroe in 1989, the U.S. and Canadian governments required some ocean ships to flush ballast tanks with sea water before entering the lakes. But those regulations only applied to about 15 percent of ocean ships, and the number of exotic species has continued to increase.

 

Starting this year, all ocean ships must flush ballast tanks with salt water from the Atlantic Ocean before entering the Great Lakes.

 

The U.S. Congress and the Coast Guard have been working for years to develop rules requiring ocean ships to clean ballast tanks with filters, heat or chemicals. Shipping industry officials have been reluctant to install costly ballast water treatment systems until there is a standard they must meet.

 

 

Chronicle file photo / Zebra and quagga mussels have contributed to a decline in prey fish, which has caused larger predatory fish like salmon and whitefish to shrink in size.

 

As politicians, bureaucrats, shipping industry officials and environmentalists debate the best way to keep ocean ships from importing more exotics, the existing invaders continue to cause profound changes.

 

Despite the numerous problems they have caused, zebra and quagga mussels have had some beneficial impacts, Jude said. By changing the water chemistry of the lakes and concentrating most of the fish food on the lake bottoms, Jude said the mussels are returning lakes Michigan and Huron to their more natural condition.

 

But the fact that the mussels are hogging much of the food at the bottom of the food chain does not bode well for fish at the top, Nalepa said.

 

"Something has to give," he said. "In Lake Michigan, which has such a huge biomass of quagga mussels, that energy has to be take from some other component of the food web."

 

There were 881 million pounds of prey fish in Lake Michigan in 1989, the year zebra mussels were discovered in the lake. Last year, that figure dropped to 66 million pounds, a record low for the second straight year.

 

The volume of zebra and quagga mussels in the lake went from zero in 1989 to 540 million pounds last year, according to government data. Quaggas mussels now account for 99 percent of all mussels in Lake Michigan, Nalepa said.

 

Quagga mussels are suspected of decimating a shrimp-like organism called diporeia in lakes Michigan, Huron and Ontario. Diporeia was the most important source of food for prey fish in the lakes, the small fish eaten by salmon and lake trout.

 

Quagga mussels are suspected of contributing to the 2004 crash of Lake Huron's salmon population.

 

Charter boats on Lake Michigan have caught near-record numbers of salmon the past two years, but the fish are much smaller than 20 years ago, according to anglers and state data.

 

Drew Morris, a second generation charter boat operator in Muskegon, said zebra and quagga mussels have affected the size of salmon in Lake Michigan, water clarity and the techniques used to catch fish.

 

"It's completely changed how we fish," said Morris, owner of Margie J Sportfishing Charters. "We're obviously hoping the mussels don't disrupt the food chain to the point that we lose the salmon."

 

Morris said Lake Michigan is now clearer than he can remember in the four decades he's been fishing and swimming in the lake. That's good for swimmers but bad for anglers trying to sneak up on fish.

 

"I was cruising outside the south break wall (at Muskegon) a couple of years ago and I could see the bottom of the lake -- it's about 28 feet deep at that point," Morris said. "I was never able to see the bottom of the lake at that point. It looked like the ocean."

[Reef Runner]

Very interesting read. As I don't travel in my boat from the great lakes inland, I wonder, is there any similar regulations for pleasure craft monitering the proliferation of these mussles into our inland waters ie., the Trent-Severn and others? I can really see the hazards to our shallower, warmer lakes such as the Kawarthas.

 

reefrunner

[Ramble]

They are already in some of the Kawarthas

 

-R-

[Mike the Pike]

Interesting read leave it up to the government to turn the other way should have implemented stiff rules for the ships years ago.

 

Worst of all not much is being done right now.

 

Won't be long and we will have to deal with the asian Carp.Which the US goverment is ignoring.Enjoy the fishery we have now because it sounds like it will be lost in the near future.

 

MTP

Edited April 17, 2008 by Mike the Pike

[irishfield]

Yes the ships brought it in Mike... but blame the fisherman after that for the other places it is now. Just like Spiny water flea.. it didn't get to Temgagmi on it's own... it got there from someone that didn't wash their boat and gear between Lake O and Lake T. Keep that in mind when you fish BOQ and then head home and North of Montreal the following weekend to a pristine Lake. Stop in Deseronto and blast the crap out of your boat at the car wash. Bleach your live wells as well if they won't completely dry.

[Mike the Pike]

Yup the power wash is a good thing its too bad some places are over charging to do it here in Quebec.

 

20 to 30 to park and wash ones boat.Yup add that to our new found gas prices and it is getting expensive to go fishing.

 

Fishing is my stress relief.

 

I wonder how come the Salmon in the great Lakes are getting smaller but the Muskie in the ST.Lawrence are huge and the Larry is infested with Zebra mussels.

 

[Reef Runner]

That's real interesting stuff.

 

I wonder if the asian carp reduced the numbers of jet skiers? Be prepared to boat around in a helmet.