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Things that go crunch in the night

Published Aug. 28, 2005

The whiskered brown animals initially seemed charming, playfully diving around the pond behind Pam Kyak's home in the Heather Lakes subdivision.

She and her neighbors thought a family of otters had moved in.

Then a pest began terrorizing her garden. At night, sharp teeth tore at her flowers and shrubs. A banana tree was gnawed to its roots. Holes sprouted around her lawn.

One day, Kyak dug out binoculars for a closer look at her pond-dwelling neighbors. She saw long, skinny tails and clawed feet. A chilling row of orange-red incisors came into focus.

"Oh, my," said Kyak, 45, a health care administrator. "I can't take this."

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The critters in her pond were not otters, but rodents called nutria.

Nutria thrive where water meets land. They establish underground nests, eroding the banks of rivers, lakes and ponds.

Formally named Myocastor coypus, the rodents are the swamp equivalent of a Manhattan sewer rat. They grow as heavy as 20 pounds, with round tails 13 to 16 inches long. The nocturnal herbivores prefer the succulent portion at the base of plants and can eat 25 percent of their body weight daily.

Nutria never belonged in the United States. Fur ranchers imported them from South America around the start of the 20th century, hoping to profit from their shiny fur coats.

The market for nutria fur never materialized. Some disappointed farmers released the nonindigenous animals into the wild. Others escaped. In time, a sizable population roamed the marshes of Louisiana. A hurricane helped spread nutria along the Gulf Coast.

"They are survivors," said James McCann, a retired researcher with the U.S. Fish and Wildlife Service in Gainesville and author of a 1996 report on nonindigenous species. "They can adapt to a situation, and they can do quite well in the climate that we have in Florida."

The slinky animals followed several paths to West Central Florida. In Pinellas County, the rodents were released intentionally as biological control agents to reduce vegetation around the water. They have been seen in swampy areas of Tampa and Pasco County.

Nutria undoubtedly witnessed the transition of rural land around Brandon into densely populated subdivisions. And manmade lakes and ponds in new developments made it easy for them to thrive.

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The problem began in Heather Lakes when residents decided to remove the water hyacinth from the ponds. For years, the nutria had nibbled at the leafy plants. Because the plants were growing out of control, food was plentiful.

After the water hyacinth disappeared, nutria began savaging lawns in Heather Lakes.

The best estimate has 100 nutria living in four ponds in the community. Incensed neighbors half-jokingly plan to import alligators to control the population.

On Lochmont Drive, Kyak took matters into her own hands.

The 12-year Heather Lakes resident wasn't confused anymore about the identity of the rodents. She decided last year to set a trap in her yard. She found cabbage on sale, stuffed the greens into the cage and waited.

It took weeks to discover the right bait. One night, Kyak loaded the cage with chopped bits of carrot and tomato, discards from a meal.

At daybreak, a hissing nutria awaited her.

She remembers running every red light on the way to Plant City, where a brother-in-law had promised to take the creature off her hands. She didn't ask what he planned to do with it.

Nine nutria later, the fear factor was gone.

"It really did take care of the problem for a while," said Kyak, who recently entertained the thought of laying out the bait and traps again. But "they multiply."

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Once nutria invade, they affect entire ecosystems.

Nutria eat plants that support other animals. They destroy habitats. Their numbers multiply quickly, with females bearing an average of four to five babies three times a year.

So far, Florida has been spared the worst of the nutria invasion.

In Louisiana, the animals _ millions of them _ are blamed for degrading more than 60,000 acres of wetland, much of that because of erosion from burrows in low-lying area. Their tunnels average 4 to 6 feet long, but 150-footers have been recorded.

They also have caused extensive damage at Chesapeake Bay in Maryland. State and federal agencies in Louisiana and Maryland are working to control nutria populations.

Some ecologists consider nutria a biological time bomb in Florida. At any point, the population could explode. They have few natural predators. When threatened, nutria may bite and scratch humans and pets.

"Could they get worse in Florida?" said University of Tennessee professor Daniel Simberloff, editor of Strangers in Paradise: Impact and Management of Nonindigenous Species in Florida. "I've often wondered why they haven't already."

Simberloff, who formerly taught at Florida State University, noted that nutria are extremely difficult to remove once established. In the 1970s, he said, an eradication effort in the United Kingdom took 15 years to see success.

Heather Lakes is battling its nutria alone. The homeowners association is paying $20 per nutria to a trapper, plus a $300 setup fee. It may not be enough.

"In another year and a half, you could have 50 more," said Scott Laugherty, president of the Heather Lakes at Brandon Community Association. He noted that the nutria likely wandered in from other subdivisions.

Eradicating the nutria living in the 1,200-plus-home subdivision is a daunting assignment even for veteran trapper Jeff Yorns.

To tally the scope of the infestation, Yorns spent several nights watching animals in their habitats. The Army veteran uses sniper tactics to combat the rodents, dressing in dark clothes and stepping stealthily when he sees a nutria's telltale circular waves.

At night, the Land O'Lakes professional lays the traps, returning in the morning to remove the captives.

"We're up to 20," he called out to a woman sitting on a screened porch, striding unannounced across her yard with an airgun under his arm.

His goal is to reduce the damage caused by the rodents, which have eroded the edges of some lawns several feet and are destroying plants other animals need.

"The best I can hope for is to bring the population down to a tolerable level," he said. "They're really upsetting the balance of nature."