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Scientists Batttle Aquatic Invaders

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By SILVIO LACCETTI and CHARLES KONTOS Special To The Tampa Tribune

The Tampa Tribune

Published: August 4, 2008

Armed with voracious appetites and explosive reproductive capabilities, giant rat-like swamp creatures from another continent lurk deep within a dark, otherworldly bayou. Rustling near the base of an ancient moss-covered tree reveals an invasive rodent called the nutria - scientific name Myocastor coypus - which has unleashed a torrent of environmental devastation along the Gulf Coast in the wake of Hurricanes Katrina and Wilma. It sounds like something out of a 1950s horror movie, but these semi-aquatic mammals are wreaking havoc right now on the natural ecosystem of Louisiana, Florida and other nearby states. Reports indicate that over 300,000 acres of wetlands have been destroyed by nutria in Louisiana.

But it's not their fault. Humans are to blame for importing nutria to Louisiana in the 1930s from Argentina, Bolivia and Brazil to profit from harvesting their furs. A hurricane in 1941 dispersed a good number of nutria into the wild, and by 1958 the animals had caused enough damage to be taken off the list of protected species. When the fur trade collapsed in the early 1980s, the critters multiplied to prolific levels. Since then they have dramatically altered the environment by consuming vegetative cover and increasing soil erosion which magnifies the most pressing issue - loss of wetlands.

And, the nutria have been spread well beyond Louisiana to become a major problem all along the Gulf of Mexico, from Texas to Florida. They have moved north along the Atlantic coast from Georgia to Delaware and Maryland, where particularly fierce battles against them have been fought.

Florida is reported to have millions of nutria, many concentrated in the Gulf Coast region from the Panhandle to Tampa. Some arrived through migration from Louisiana, Mississippi and Alabama. Some were deliberately introduced into the state to control undesirable vegetation - the program was a failure - and others escaped from fur farms. A 1959 Florida law described nutria as "...an undesirable alien that residents of Florida should eliminate on sight."

So can these aquatic South American invaders be stopped? One way is simply to trap them as humans have done for centuries. Using bait such as corn, alfalfa, cabbage, carrots, and just about any other crop, metal cages or snares are set in areas where nutria are prevalent. Louisiana is offering $5 for each "harvested" nutria.

Another way to reduce the nutria population is to bring 21st century technology to the aid of trappers and hunters who are still using methods going back to the Stone Age. Known as chemical prospecting, this innovative research field utilizes advanced scientific procedures to conduct pharmacological screening of natural biological compounds. Simply put, scientists try to identify chemicals made by animals that may prove useful to humans. Many conservationists view chemical prospecting as the major impetus for preserving the biodiversity of the planet. For example, the anti-cancer drug Taxol was developed from the Pacific Yew tree which could have been irrevocably lost through deforestation.

Now Dr. Athula Attygalle at Stevens Institute of Technology has implemented this approach in the battle against the nutria. Recently, Professor Attygalle has identified the specific chemical compounds that act as natural attractants which consistently lure nutria into traps. Application of these attractants offers an environmentally acceptable alternative to poisoning and may prove more effective than shooting campaigns or construction of expensive exclosure fences as in Louisiana.

The nutria outbreak speaks to a much larger, insidious phenomenon that is obliterating cultures and decimating natural ecosystems on a global scale - homogenization. As international travel and commerce has increased exponentially, a myriad of species have been transported across the planet, often to regions with no natural defense against the new arrival.

Silvio Laccetti is a national columnist and a longtime professor of social science at Stevens Institute of Technology. Charles Kontos is an environmental engineer.

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