Invasion of voracious, alien snails threatens Georgia wetlands

<p>A ravenous, fast-breeding South American snail is posing a threat to Georgia's wetlands and to vegetation that supports a host of aquatic species from common catfish to rare black-banded sunfish.</p><p>Biologists say the invasion of channeled apple snails is worse than they initially thought when the species was first discovered in January in southeast Georgia's Alabaha River, 20 miles north of the Okefenokee Swamp, a 396,000-acre natural wildlife refuge that is one of the nation's environmental jewels.</p><p>"It's a perfect invader," said Brett Albanese, a wildlife biologist with the Georgia Department of Natural Resources. "A wetland is a perfect habitat for apple snails. We're very concerned these things could get established in the Okefenokee Swamp."</p><p>The snails are often spread through the pet trade as aquarium enhancements, even though it's illegal to ship them across state lines. Georgia officials initially thought the single snail found in January came from an aquarium. But now that they've found many more, and they believe the marauding mollusks hitched a ride on boats or boat trailers from Florida, one of several Southern states with known breeding populations.</p><p>The snails spread quickly through streams and ponds; they can also travel over land, but at a snail's pace, of course.</p><p>Apple snails are edible, but it's unlikely they'll wind up as escargot served in fine restaurants since they can host rat lung worms, tiny parasites that migrate to the brain and spinal chord and cause a type of meningitis which can be fatal. Humans can also ingest the worms by eating lettuce slimed by infected snails during their slow, undulating travels.</p><p>The state confirmed the discovery of the first apple snail near Blackshear, a town of 3,300 about 200 miles southeast of Atlanta. Since then, snails and eggs have been found in several ponds and streams in the Alabaha River system, all within five miles of Blackshear. The Alabaha is a tributary of the Satilla River, a major southeast Georgia river system. During a recent search, biologists removed 79 snails and 151 egg masses from a pond in less than four hours.</p><p>Females begin laying clumps of 100 to 1,000 bright pink eggs at about two months of age and they keep doing it repeatedly throughout a long reproductive cycle. Their eggs hatch in about two weeks, producing snails with coiled, yellow-to-brown shells that can reach the size of baseballs.</p><p>Because of the abundance and spread of the snails since the initial discovery, Albanese believes the snails have been in Georgia for several years. Biologists want to conduct a more extensive survey to learn more about the population and to consider control options.</p><p>The state has posted signs throughout the area, urging anglers and others to report snail sightings, and has created a database to monitor the snail's spread.</p><p>"It's very difficult to predict how this nonnative species is going to interact with our native species," he said. "I think the most likely impact is by grazing on aquatic species.</p><p>"Plants are critical components of aquatic systems and provide habitat and food for many species of fish and invertebrates," he said.</p><p>Aquatic plants also help to keep rivers and streams clean. Through a process known as nutrient cycling, they remove nitrogen and phosphorus that contribute to pollution.</p><p>In other parts of the world, channeled apple snails have ravaged rice crops in southeastern Asia and attacked the Hawaiian specialty crop taro, a potato-like plant that grows in the moist soils of the tropics.</p><p>Bob Howells, a fisheries research biologist with the Texas Parks and Wildlife Department, said the snails were introduced to Taiwan from South America in 1979 as a moneymaking opportunity for would-be escargot farmers. They were also shipped to Japan, Vietnam and the Philippines.</p><p>The escargot market never developed, leaving hordes of worthless snails that were released or escaped, said Howells, an authority on channeled apple snails.</p><p>"The snails ... are now devastating the rice crops throughout the area," said Howells.</p><p>So far, the snails have not attacked crops on the U.S. mainland, even though they were discovered five years ago in canals used to irrigate Texas' rice crop, Howells said.</p><p>Besides Texas, Hawaii, Florida and Georgia, apple snails have been reported in Louisiana, California, Alabama, Arizona, Ohio and North Carolina.</p><p>Although it's illegal to import or ship channeled apple snails across state lines, the pet trade continues to sell them, said Dore Mobley, spokeswoman for the federal Animal and Plant Health Inspection Service.</p><p>The agency is stepping up enforcement efforts, including requiring regular inspections of aquatic supplies shipped into the United States, and it has formed a group to study the threat.</p><p>"There are a lot of unknowns in terms of the exact damage that it's going to cause," Mobley said.</p><p>---</p><p>On the Net:</p><p>HASH(0x1cdf814)</p><p>HASH(0x1cdf8bc)</p>

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