Ratlike nutria show damage that nonnative species can cause

  • Fri Feb 17th, 2012 7:34pm
  • Life

By Sharon Wootton

The list of unintended consequences that humans fail to realize (or ignore) before committing is long.

Want to raise fur-bearing animals? Import nutrias from South America, starting in California in 1899. Don’t worry about the escapees. Fur market collapses? Release the animals.

Or sell the plant-eaters to control noxious weeds in wetland areas. Decades down the road, resort to killing the countless generations of prolific-breeding descendants because, not knowing they were to stick with the weeds, the nutrias also ate native aquatic vegetation and nearby crops.

The worse destruction came from decimating the banks of lakes and freshwater and brackish marshes because the nutrias ate native plants that prevented erosion, reducing important habitat as well.

Welcome to Nutriaville, where the semiaquatic 2-foot-long rodents (plus a 12- to 16-inch tail), also known as swamp rats, better the native wildlife.

More than 600 nutria farms operated in Washington and Oregon in the mid-20th century. While Washington doesn’t have the extreme nutria problem that Louisiana and other states have, it would be foolish to be lulled into complacency.

Nutria have been trapped and caught along the shores of Lake Washington. Skagit County has had to deal with them for years, in part because they burrow into its dikes and weaken the structures. The burrows can be up to 18 feet long.

There have been many eradication programs in many states, but for some states, such as Louisiana, it’s too late to reset the dial to zero.

Also on the downside, nutria can be infected with tularemia, a bacterial disease that can be spread to humans through biting insects or contact with the animal or its feces.

Swamp rats prefer the tasty lower stems of plants, destroying a plant for about 10 percent of its area, a process that often involves pulling up the root system. Since the ravenous nutria eats about 25 percent of its body weight each day, the swamp rat and its kin’s daily intake can decimate an area.

Other nutria-related number:

•Adults weight 12 to 20 pounds.

Two large yellowish-orange incisors, prominently displayed.

Can stay submerged up to 10 minutes.

Nutrias stay near water; most travel no more than 600 feet from home.

Few nutrias live longer than three years in the wild, which is good because males are ready for sex at 4 to 9 months of age; females are ready at 3 to 9 months. That can mean two litters and pregnant with a third in one year.

Average litter size is five but can have as many as 13.

Fifteen states have stable or growing populations.

Each year millions of dollars are spent to eradicate nutria in several states because large populations can cause billions of dollars in damages.

Last fall, the U.S. Department of Agriculture’s Wildlife Services sent out teams to kill nutria to protect places such as Blackwater National Wildlife Refuge in Maryland.

If all else fails, there’s always the nutria-as-delicacy option, perhaps an opening for an entrepreneur. One New Orleans recipe is ragodin au choux rouge (nutria with caramelized red cabbage and honey mustard sauce); another is to take the meat, said to taste like rabbit, and turn it into nutria sausage.

The swamp rat is, after all, high in protein and low in fat, according to Louisiana’s Chef Philippe, who one year helped stage a nutria dinner in New Orleans with a nutria fur coat fashion show.

Columnist Sharon Wootton can be reached at 360-468-3964 or www.songandword.com.