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THE NATION

Mrs. O'Leary's Cow, Meet the Asian Carp

July 19, 2002|ERIC SLATER | TIMES STAFF WRITER

CHICAGO — At the rate of 35 miles a year, the carp have migrated north, leaping so high at times they have smacked the boat-borne fishermen and researchers in the face.

They are almost here now and, beyond their unexplained aerial assaults, pose what biologists believe may be a major ecological threat to North America's largest water system.

Fat, voracious and with a complexion only a dermatologist could love, Asian carp are just 25 miles from this city's downtown entryway to the Great Lakes. The only thing standing in their way is an experimental electrical curtain.

As long as 5 feet and weighing up to 110 pounds, the carp eat as much as half their body weight daily in plankton, the same food virtually every other fish in the lakes eats when it is young. They breed so quickly that Australian biologists call them "river rabbits."

"They could essentially wipe out the base of the food chain in the entire Great Lakes," said Dennis Shornak of the International Joint Commission, which oversees water systems that affect both the United States and Canada. "We could honestly end up in a situation where the Great Lakes are nothing more than a carp pond."

With the fish approaching, the commission has taken to lobbying the highest levels of the U.S. and Canadian governments for help, including Secretary of State Colin L. Powell, since the issue is of international concern. But many fishery biologists are skeptical that the carp can now be kept out of the Great Lakes and are beginning to consider how to mitigate the damage.

Mitigation has become the less-than-ideal method of battling other invasive species that couldn't be kept out of the Great Lakes, such as the zebra mussel, which made its way from Europe in the 1980s, transported in the ballast water of ships.

No longer does anyone expect to rid the lakes of zebra mussels, only to continue fighting the creatures, which attach themselves to ship hulls, bridge pilings, other mussels and drinking-water intake systems. The bill for fighting the mussels throughout the lakes: $3 billion in just a decade.

Asian carp, scientists fear, could do exponentially more damage than zebra mussels or any other of a handful of invasive species in the Great Lakes, including sea lampreys, which decimated trout populations 50 years ago. They are likely to compete for food with such commercial fish as paddlefish, gizzard shad, bigmouth buffalo, and virtually every other fish while they're in a larval stage. And once they get in, there is no getting them out.

They pose another problem. These fish can jump--more than 12 feet out of the water.

"It's not a phenomenon you have to wait for," said Pam Thiel, a fishery expert for the U.S. Fish and Wildlife Service in La Crosse, Wis. "Just go to a place where they are dense and they will be flying."

A most impressive sight, from afar.

"They don't mix well with water-skiers, jet-skiers and boaters," Thiel added.

Some commercial fishermen have taken to protecting themselves from incoming carp with cookie sheets or garbage can lids. A fisherman on the Kaskaskia River in southern Illinois suffered a broken nose when one leaped into his face.

Virtually every researcher for the Illinois Natural History Survey, which studies area fisheries, has taken at least one carp hit, said Kevin Irons, a river ecologist with the group. One ichthyologist, who already had been whacked several times, was injured so badly during a recent flying-carp encounter that he is receiving medical treatment.

With large, mottled scales and eyes that seem to have slid halfway down their faces, Asian carp are considered trash fish of the lowest order in the West.

Although their white, low-oil meat is rather tasty, many agree, the fish--probably because it is a carp--has never gained a market in North America beyond the Chinatowns in a few major cities. And even where there is a market, the fish must be trucked there alive because, as with lobsters, connoisseurs prefer them fresh.

The much-maligned carp do have a place to call home. Halfway around the world in East Asia, the arrival of a migratory school would likely be greeted not by an electric shock but a celebration.

In much of China, carp are not only a food staple but symbols of strength for their mythic ability to leap the entire rapids of the Yellow River, and perseverance for their actual talent at swimming upstream. They are common images in watercolors and other artwork, often pictured leaping high out of the water, twisting in the air with gusto and grace.

Two species of Asian carp, bighead and silver, are the primary cause of concern here. Imported by Arkansas fish farmers in the early 1970s for their skill as underwater vacuums, the carp were slipped into catfish ponds to gobble up algae blooms.

The fish escaped, as it were, during heavy floods in the early 1990s, making their way out of the ponds and into tributaries of the Mississippi River. They swiftly swam north.

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