Nutria - Overpopulation within the Ecosystems

Another issue that plagues the wetlands is the overpopulation of nutria. Nutria, also known as coypu, are semi-aquatic rodents that are not indigenous to in the United States. These rodents traditionally come from Argentina, Brazil, Chile, and other South American countries. Nutria were originally introduced to the United States in 1899 to California and can presently be found in 15 of the 50 states. In the early 1930s, the nutrias were imported from fur farms into the wetlands of Louisiana to be hunted in fur trades. The nutria were on the move when trappers moved them to Port Arthur, Texas and the Mississippi River area before a hurricane would disperse them further.

Nutria would aid in controlling the weeds in the wetlands through the late 1940s. They would be the primary consumers of water hyacinths that were throughout Louisiana. Their reproductive cycle being exponential helped with rapid population growth. The US Geological Survey discusses the reproductive cycle of the nutria in an article titled “Nutria, Eating Louisiana’s Coast”. The article stated that nutria reach sexual maturity at six months of age and has a gestation period of only 130 days. In a single year, adult nutria is capable of producing two litters in a year of four to five; however, they are capable of birthing up to 13 in a single litter. The baby nutria are also born fully furred with their eyes open.

The nutria population by the 1950s was above 20 million, and the nutria had destroyed natural levees. The nutria were destroying other agricultural areas were being destroyed, leading to their removal from list of protected wildlife near the end of the 1950s. Louisiana promoted fur as a natural resource because of their overabundance. From the early 1960s through the early 1980s, hunting the nutria and hurricanes and other severe weather would help aid in reducing their population. The fur trade went bad in the late 1980s so the only consumer of the nutria then would be the alligator. Damage could be seen in satellite imagery through the 1990s and in 2002, a program was put in place to reduce the numbers further.

Sources:

http://www.nwrc.usgs.gov/factshts/020-00.pdf

http://www.sciencedaily.com/releases/2008/03/080306094624.htm

http://www.nutria.com/site2.php