Hardly gentle little balls of fur nutria carry parasites that have infected people and pets. Hunters who have caught "nutria itch" by walking in nutria-infested waters describe intense discomfort and inflammation caused by a nematode expelled in the nutria's feces. Nutria carry roundworms salmonellosis and a spirochete that cause illness and infection. Fortunately none of these are fatal. A nutria's sharp teeth can injure another animal - or pet. This nocturnal fur-bearing rodent lives for only five years but in that short time its population increases substantially. Each female can have five litters every two years according to Dr. Robert Chabreck of the LSU School of Forestry Wildlife and Fisheries. In 1995 Jefferson Parish asked Chabreck to determine the size of the nutria population in the parish and to evaluate various means of controlling it.
Nobody knows for sure how many nutria are living in Jefferson Parish. Chabreck and Dr. J. Andy Nyman estimated the Jefferson Parish nutria population at about 10 0 animals by using a process called population indexing. The scientists counted the number of nutria in a particular area and then estimated based on similar space and food availability the number that might be living in the rest of the parish. This number is an "educated guess." The number is impossible to fix because nutria don't live forever in one place. If the grass looks greener somewhere else they move and unlike humans they don't have any reason to provide others with a change of address.
In the formal report from their study Chabreck and Nyman describe several alternatives to control this nutria population. All are based upon biological economic and social consequences of different control measures as well as public safety animal welfare and cost effectiveness. The alternatives fall into two categories: (1) to make canals resistant to nutria damage or (2) to reduce the number of nutria in the canals. Although the first alternative is simple - to line the canal banks with concrete or similar material - it is very expensive. Jefferson Parish has 280 miles of drainage canals and the cost of lining banks is about $ 3 0 per linear foot around $15 million per linear mile according to Winters. That leaves reducing the number of nutria in the canals - somehow.
You can reduce the number of nutria by nonlethal or lethal methods " Chabreck said. Nonlethal methods could include somehow stopping nutria reproduction or relocating the animals. These are easy to define and impossible to do. No practical and acceptable contraceptive methods are available and other suitable nutria habitat in Louisiana would also suffer the same adverse impacts.
The lethal methods - trapping shooting and poisoning - are controversial. "Shooting has been an effective wildlife damage control tool for eliminating small isolated groups of animals rather than for reducing the numbers of widespread populations " Chabreck said. Although Sheriff Lee's SWAT team has killed about 3 500 in the past year the population is probably still around 10 0 The reproduction rate plus migration from neighboring parishes and waterways will more than compensate for the ones that are killed. >Next>
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