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Great Lakes Article:

Invaded waters
By Tom Meersman
Star Tribune
Published June 13, 2004




The Great Lakes have become a giant outdoor biology experiment -- with no one in charge.

In the space of a few decades, an evolutionary snap of the fingers, vast populations of foreign fish, mussels and other creatures have invaded and damaged irreversibly an ecological design that took thousands of years to evolve.

These unwanted guests in the largest freshwater system on the face of Earth have muscled out native species, killed thousands of loons and other migrating birds, devoured food resources, clogged water-intake pipes and begun to spill into many of North America's premier interior lakes and rivers.

Many scientists say the invaders are a worse problem than the industrial contamination that fouled the Great Lakes in the 1960s.

They can't be mopped up like a spill or turned off like a faucet. Some scientists think of the invaders as biological pollution: They adapt, reproduce and spread. No one species of invader has been eradicated. Many have no native predators to keep them in check.

Unlike industrial pollution, much of the new damage is nearly invisible, hidden in the lakes' murky depths. Yet biologists who study lakes say the evidence is mounting that the unintended introductions of species from around the world could soon dominate the lakes' ecology.

The onslaught also affects Chesapeake Bay, San Francisco Bay and other North American marine systems, but the Great Lakes are special because of their immense stores of fresh water. Some changes could pose a threat to humans, and health experts have issued warnings about the risks. Botulism and bacteria that cause cholera are documented consequences of the invasion. So far, no humans have been reported ill.

At stake is a resource that millions of Americans and Canadians rely on for drinking water, recreation and their economic livelihood.

Many experts say the governments of the United States and Canada have not done enough to stop potential new invaders.

One paradox is that the lakes' improved water quality of the past three decades, especially in harbors, may help the foreign creatures flourish.

The invasion of alien plants and animals -- 179 of them by the latest count -- began in the early 1800s, and it picked up steam after the St. Lawrence Seaway opened the lakes to oceangoing ships in 1959. More than 40 percent of the Great Lakes' invaders have been discovered since then and most arrived by ship from Europe or Asia, according to research data analyzed by the Star Tribune.

A new invader is identified in the lakes about every seven months.

"They're coming in faster than we can study them," said Assistant Prof. Anthony Ricciardi, invasive species biologist at McGill University in Montreal.

Another scientist who has studied the Great Lakes basin for 50 years now describes it as "a sick system." Henry Regier, a professor emeritus of zoology and environmental studies at the University of Toronto, said he has never seen such dramatic changes in the lakes.

The alien species have created an "accidental zoo," said Prof. James Carlton, director of the Maritime Studies Program of Williams College in Mystic, Conn. The lakes, he said, have been permanently modified "on one of the greatest scales in any aquatic environment in the world."

To be sure, nature changes on its own over time. Aquatic populations fluctuate, and some creatures migrate to new areas or go extinct. And not every introduced fish, worm or plant disrupts the environment.

Some people question the severity of the problem, but even the shipping industry concedes that it has transplanted unwanted creatures around the globe.

North American species also have hitched rides aboard foreign-bound vessels. An East Coast jellyfish, for example, invaded the Black and Caspian seas in the 1980s and severely damaged the anchovy industry and other fisheries.

The unnatural mixing of species from around the globe has made it an important time to be a biologist studying the Great Lakes. Researchers are making surprising discoveries about the invaders and publishing them in scientific journals.

It also is a deeply frustrating and depressing time for scientists. None can predict how this grand accidental experiment will play out. And it's possible that the next generation of researchers will look back on 2004 and remember the Great Lakes as a system whose ecological collapse wasn't averted in time.

Scientists rarely make guarantees, but their observations about the current state of the lakes are consistent in dozens of studies: The doors for invaders to enter North American waterways are wide open, and the Great Lakes are fighting for their lives.

Dying loons

Nowhere has the destruction been more apparent than on the shores of Lake Erie. Each fall, the skies above the lake are filled with the flapping wings of loons migrating south along ancient routes from northern Canada.

In flashes of black-and-white feathers, the loons swoop down to Lake Erie to rest and dive for fish. Frequently they snatch the round goby, a 4-to-6 inch European fish with bulging eyes that has found a new home in the Great Lakes.

Often the meal is a death sentence.

Scientists say the gobies become toxic food by ingesting quagga mussels, another recent invader from Europe, which accumulate botulinus toxin from the lake bottom.

After a loon feeds on a tainted goby, poison attacks the bird's nervous system, researchers say. The loon's legs stop working. Soon, it can't flap its wings, hold up its neck, or keep its eyes open. Within hours, helplessly paralyzed, the loon drowns and either sinks or washes up on shore. More than 50,000 loons and other birds died after eating gobies and quagga mussels over the past five years -- victims of poisoning.

So many dead birds have washed ashore during recent fall migrations that beach patrols hauled them away with ATVs and flatbed trucks. Jason Telecky, a wildlife technician with the New York State Department of Environmental Conservation, walked the beaches for two years removing the carnage so that the botulism in dead birds and fish wouldn't spread to pets and scavengers. Telecky said his friends jokingly called him "Dr. Death," but it wasn't funny after a while.

One afternoon in November at Lake Erie State Park, Telecky came across a loon with its wings splayed and its body half-buried in sand. He pulled on a pair of latex gloves, hoisted the heavy, saturated bird by its legs, and dropped it into a large plastic bag held by an assistant. About 50 feet away was another loon, its body half-eaten. Farther down the beach was the apparent scavenger: a dead raccoon, flat on its back, teeth locked in a grisly grimace.

Loons and other native species evolved in the Great Lakes after the last Ice Age, about 10,000 years ago. What developed was a rich, layered freshwater ecosystem isolated from the rest of the world. It contained 150 species of fish and innumerable other creatures, a complex mix of predators and prey.

A critical link in this food chain are the quarter-inch Diporeia, pale-orange shrimplike organisms that live on the bottom of lakes. Loaded with fat, they long have been a high-energy, abundant food source for fish in the Great Lakes.

Over the past decade Diporeia have vanished from more than 17,000 square miles of lake bottom -- an area more than twice the size of New Jersey.

Every lake except Superior has been affected. Scientists began to document the losses in the early 1990s, in areas where zebra or quagga mussels had invaded. As the fish food disappeared, so did native fish, especially the commercially valuable whitefish, which depend on Diporeia for up to 70 percent of their diet.

The stories of the loons and Diporeia underscore the difficulty of predicting how invaders can undermine native species. Scientists thought they had learned much about zebra and quagga mussels, but the loon-killing botulism came out of the blue.

As for the tiny shrimplike creatures, "no one in their wildest dreams thought that Diporeia would be affected," said research biologist Bob O'Gorman, who has studied the Lake Ontario fishery for the U.S. Geological Survey.

Rapid change

The speed and success of a single species' invasion can be stunning.

Scientists found a few dozen Eurasian ruffe in the Duluth harbor in 1986. The small, spiny, perch-like fish from Europe exploded to 2 million by 1991 and to more than 8 million in 1998, before declining slightly, according to federal estimates. It now is the most abundant fish species in the harbor.

One reason that some invasive species are surviving and proliferating is that harbors and estuaries are cleaner today. Taxpayers and industries invested billions of dollars to improve sewage treatment, remove phosphorus and reduce chemicals, allowing the Great Lakes and their native fish and wildlife to progress toward recovery during the 1970s and 1980s.

Invaders are undercutting those achievements. The changes affect not only fish, but also the smallest plants, invertebrates, snails and mollusks. For example, 20 species of native mussels lived in Lake St. Clair, part of the waterway between Lake Huron and Lake Erie, in 1986. Two years later, zebra mussels spread into the lake. By 1997, all of the native mussels were gone except in a few shallow areas.

Non-native mussels also have fouled beaches, leaving mounds of sharp shells and decaying, smelly flesh. In one extreme example, zebra mussels piled up two feet deep and 15 feet wide along a quarter-mile of beach near Green Bay, Wis. In lake cities such as South Haven, Mich., anglers fishing offshore often reel in unwanted non-native fish.

Invaders also pave the way for future intruders.

The newcomers sometimes alter the habitat in ways that help other alien creatures to thrive.

For example, invasive gobies spread quickly in areas where zebra mussels have become established because the gobies eat the mussels. In other places, zebra mussels attach themselves to non-native Eurasian watermilfoil plants. The mussels gain a place to live, while the milfoil grows better because the clinging mussels filter and clear the water.

This positive interaction between foreign species represents a dangerous shift in the lakes' ecology that has been called "invasional meltdown." University of Tennessee biology Prof. Daniel Simberloff, who coined the term, said damage to native creatures may accelerate if clusters of invaders remake the aquatic habitats. The biggest losers could be native species that already are endangered, he said.

Invaders also pose human health risks. The botulism outbreak that killed loons and other birds also poisoned hundreds of thousands of fish. New York officials issued health advisories warning anglers not to handle or eat sick fish and game. No human cases of botulism have been reported.

Scientists are concerned that pathogens could enter the United States by the same pathways that invasive species use, potentially spreading human diseases. Smithsonian scientists found bacteria that caused cholera four years ago in 15 ships' ballast tanks in the Chesapeake Bay, for example. Again, no human illness was reported.

People with decades of experience fishing on the Great Lakes have seen both warning signs and actual damage. For Don Scott, a fishing guide in Ontonagon, Mich., the changes have meant that customers who fish for northern pike and walleye spend much of their time hauling in 4-inch Eurasian ruffe. The fish's populations have skyrocketed in the Ontonagon River and other waterways. "We get slammed with them," Scott said.

Sportsmen still catch native fish, but that may not be true in a few years if the ruffe continue to expand, Scott said.

Tom Marks, a sport fisherman on Lake Erie for more than four decades, mainly blames invasive zebra and quagga mussels for a 75 percent decline in Erie walleye since the mid-1980s. The mussels feed on nutrients that young fish need to survive. Marks, who is former president of the Southtowns Walleye Association of Western New York, said the result is fewer young walleye, and a shortage of prey such as perch, minnows and smelt for the larger walleye.

How they arrive

Commercial shipping, one of the economic engines of the Great Lakes, also drives the ecological decline.

Ships have been the main carriers of invasive species into the Great Lakes. An empty cargo vessel headed for Duluth may contain 2 million gallons of water in its ballast tanks to keep it safely balanced. Virtually all of it will be dumped into the harbor as the vessel takes on grain or other cargo.

The problem is that ballast tanks also may contain thousands of organisms hitchhiking rides from foreign ports. Many oceangoing vessels are inspected under a U.S. Coast Guard program, but experts say the invaders still can find their way into North American harbors aboard ships.

Two-thirds of the invaders discovered in the Great Lakes since 1960 likely came from shipping, mostly from ports in northern and eastern Europe, researchers say.

Dozens of species from the Black and Caspian seas have hopscotched across Europe, settling in ports of the Baltic and North seas. Now, researchers say, species such as the "killer shrimp," so named because the one-inch creature devours and destroys vast amounts of fish food, soon could show up at the Great Lakes' doorstep.

Fish farms in the United States also contribute to the problem. Two kinds of Asian carp imported to clean U.S. fish farm ponds and tanks escaped into southern waterways in the early 1980s. They have spread up the Mississippi River and its tributaries toward Lake Michigan.

Fearing that the carp may jeopardize a $4.5 billion commercial and recreational Great Lakes fishery, the U.S. Army Corps of Engineers and the state of Illinois are building a $7 million electric barrier south of Chicago to try to halt the carp. And a different type of barrier on the Upper Mississippi River is being considered.

The barriers may not be enough. Invasive species also have entered the lakes through bait buckets, as anglers intentionally or inadvertently dumped them into the water. Unwanted aquarium fish have been released into waterways because their owners thought it was a humane or convenient way to dispose of them.

About a third of the invasive species in the Great Lakes basin are aquatic plants, such as Eurasian watermilfoil, which have been spread by ships, boats, trailers, garden nurseries and other means. This vegetation can overtake lakes and interfere with boating, fishing and swimming.

Cost to society

This invasion results in an enormous cost.

Take just one species: Zebra mussels, which look like thumbnail-sized clams with dark and light stripes, have cost industries, water companies and power plants nearly $2 billion, according to Chuck O'Neill, a coastal resources specialist with New York Sea Grant, an extension program of Cornell University and the State University of New York. The mussels, originally from the Caspian Sea, clog water intake pipes and other equipment and need to be removed periodically with chemicals or other means.

Other experts have tossed around damage figures in the billions of dollars for commercial fishing, recreation and tourism. But the hardship to native species is not easily rendered into dollars and cents.

Many feel that it's impossible to assign a cost to a 70-year-old endangered sturgeon in Lake Ontario killed by botulism, for example, or to the disappearance of perch and walleye from a favorite fishing hole, or to the loss of a clean swimming beach.

Putting a price on the ecological decline of the Great Lakes "is just utterly stupid and immoral," said Regier, the researcher from Toronto.

The business health of the Great Lakes also is at stake. Regulations on shipping, fish farming and the pet industry, for example, could affect trade. "We should not go back to pre-Columbian times," said Marshall Meyers, executive vice president of the Pet Industry Joint Advisory Council, a trade association that includes importers of animals sold as pets. "We are in a global economy."

Meyers said the ecological problems caused by the creature invasion are too often exaggerated.

However, taxpayers already are paying a price because it is costly to keep invaders' populations in check. The sea lamprey, an eel-like parasite that attaches itself to fish, came from the Atlantic Ocean through canals. U.S. and Canadian governments spend $16 million annually to trap, sterilize and poison millions of lampreys. The program will never eradicate them.

The lamprey, because it spawns in streams, is vulnerable to human control efforts. For most established aquatic invaders, scientists can do nothing to interrupt their life cycle.

While experts have been raising red flags about the invaders for decades, they have received little public or government attention. Almost all federal funds provided to counter foreign species are devoted to terrestrial pests that threaten agricultural crops and forests, not to aquatic invaders.

"We're completely in a reactive mode in dealing with these invasive species, in both the United States and Canada," said Prof. Hugh MacIsaac, invasion biology research chair at the University of Windsor and one of Canada's leading researchers on the issue.

Secondary invasions

The invaders have spread within the Great Lakes and beyond.

Zebra mussels, alien plants, fish eggs and larvae can be picked up in boats, trailers and bait buckets and whisked inadvertently to any fisherman's or boater's favorite spot.

That has hit home for Bob Franseen, who learned in October that Ossawinnamakee Lake in north-central Minnesota had become infested with zebra mussels. The lake, where he lives year-round, is 110 miles from the nearest known zebra mussel infestation in Minnesota. A worker found the mussels on several docks that he removed last fall. "The news came like a grenade tossed into the middle of things," Franseen said. At the time, lakeshore owners were busy trying to stop the spread of Eurasian watermilfoil.

Residents and state officials are concerned that the popular recreational lake will become the bull's-eye from which boaters and anglers inadvertently carry the mussels to neighboring lakes. Mussels, especially tiny young ones, are frequently transported in water that accumulates in boat engines, bilges and live wells, or on aquatic weeds that become entangled in anchors and boat trailers.

Natural resource authorities have redoubled their efforts to warn people about cleaning boats and trailers and emptying bait buckets on shore to reduce those risks.

Ossawinnamakee is the second lake in Minnesota where zebra mussels have been found, after Zumbro Lake in the southeastern part of the state. Michigan has 185 infested lakes, Wisconsin has 44, and Ontario has dozens, especially along a highway of interconnected lakes, rivers and canals that extends more than 200 miles between lakes Ontario and Huron.

The spread of invasive species in Ontario threatens a $1.4 billion-a-year recreational fishing industry. "We have been warning for years that invasive species in the Great Lakes like zebra mussels and round gobies were going to get into the inland waterways," said Greg Farrant, government relations manager for the Ontario Federation of Anglers & Hunters. "Well, now it's happened. They're here."

Halting newcomers

The invasion is far from over -- and stopping more destructive creatures like the killer shrimp from entering the Great Lakes won't be easy.

On ships, the ballast water and residue in the tanks would need to be filtered or exposed to heat, chemicals, ultraviolet light, ozone or other treatment to kill unwanted creatures. Ship owners are unwilling to make such changes on their own because they say that the technologies are experimental, and that government officials have not established limits for how many organisms need to be killed or removed.

In February, after years of discussion, the International Maritime Organization, a U.N. agency, adopted a convention on ballast water. It offers no immediate remedy. Ballast treatment standards would take effect for new ships in 2009 and for existing vessels beginning in 2014, if enough nations ratify the treaty.

Those regulations may be too late for the Great Lakes. Researchers have been calling for immediate action for the past 15 years. In the latest attempt to push for changes, 750 scientists, resource managers and other experts sent a letter in December to Congress and President Bush. They asked for new laws and more money to protect the Great Lakes and other areas, because "the devastation caused by non-native, invasive organisms is one of the most serious and least-recognized tragedies of our time."

For two years Congress has been studying whether to strengthen laws about invasive species. Two House subcommittees held a joint hearing in March, but it is unclear whether legislation will be passed.

U.S. officials also have considered establishing a national screening system to prohibit imports of creatures with a high potential to spread uncontrollably in the wild. Such a system already exists to exclude foreign plants that could endanger agricultural crops, but the worldwide trade in fish, aquatic plants and other potential invaders remains largely unregulated.

Fish such as Asian carp also can invade waterways through the live food market if unsold fish are dumped live into ditches, canals or lakes. Chicago, New York, and the province of Ontario recently began requiring that live bighead carp be killed at the point of sale or before disposal.

In the meantime, invaders continue to be discovered, and no one knows how much havoc the next one may wreak.

"Every time we have a new species that enters the Great Lakes, we're instigating yet another unplanned and uncontrolled biological experiment on our ecosystem," said David Reid, a research scientist at National Oceanic and Atmospheric Administration's Great Lakes Environmental Research Laboratory in Ann Arbor, Mich. "We are playing ecological roulette with the Great Lakes."

 

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