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Nutria

Nutria or coypu (Myocastor coypus) are semi-aquatic rodents native to South America that are now invasive mainly in the southern and eastern United States. Nutria were introduced into the United States in 1899 for fur farming. Nutria dispersals resulted primarily from releases by fur farmers, escapes during hurricanes or rising floodwaters, or as translocations (nutria were used in an attempt to control nuisance aquatic vegetation).

Nutria forage on agricultural crops, weaken irrigation structures by digging burrows, and have the potential to transmit disease to livestock. Crop damage is most prevalent in areas adjacent to aquatic habitats supporting nutria, and especially where nutria are abundant (Bounds et al. 2003). Crops damaged by nutria include primarily sugarcane and rice, but also corn, milo (grain sorghum), sugar and table beets, alfalfa, wheat, barley, oats, peanuts, and various melons and vegetables (LeBlanc 1994). In Louisiana, nutria commonly undermine and break through water-retaining levees in flooded fields used for rice and crawfish production (LeBlanc 1994). Nutria burrows can weaken flood control levees that protect low-lying areas as well as roadbeds, stream banks, dams, and dikes under heavy weight (LeBlanc 1994). Nutria can be infected with pathogens (e.g., leptospirosis) and parasites transmissible to livestock, which is especially a concern in situations where livestock drink from water contaminated by nutria urine and feces (LeBlanc 1994).

Nutria are a challenge to control and even more difficult to eradicate from a sizable area, but with an effective strategy and sufficient resources and effort, they can be removed from large areas. For example, Labrador retrievers are more commonly being used to detect nutria at low densities. Management plans to control nutria typically involve population reduction or eradication (Schitoskey et al. 1972, Gosling and Baker 1989, Carter and Leonard 2002).

The tools used to accomplish reduction or eradication of nutria need to be assessed based on management objectives and approach. Currently, research needs identified to improve nutria management include monitoring techniques, lures and attractants, toxicants, and multiple capture systems. Effective attractants will most likely be biologically-based or food-based olfactory cues and would serve to enhance other means of control such as multiple-capture traps and toxic bait stations. Zinc phosphide is currently the only registered toxicant for nutria and research is underway to improve its effectiveness while reducing potential hazards. Fertility control (Mach 2002) and landscape-level population and management modeling (Carter et al. 1999) may also provide useful techniques to future management.

Summary above taken from:

JOJOLA, S. M., G. W. WITMER, AND D. L. NOLTE. 2005. Nutria: an invasive rodent pest or a valued resource. Proceedings of the Wildlife Damage Management Conference 11:120-126.

Literature Cited

BOUNDS, D.L., M.H. SHERFY, AND T.A. MOLLETT. 2003. Nutria. Pages 1119-¬1147 in G.A. Feldhamer, B.C. Thompson, and J.A. Chapman, editors. Wild mammals of North America: biology, management, and conservation. John Hopkins University Press, Baltimore, Maryland, USA.

CARTER, J., A.L. FOOTE, AND L.A. JOHNSON. 1999. Modeling the effect of nutria (Myocastor coypus) on wetland loss. Wetlands 29:209-219.

CARTER, J. AND B.P. LEONARD. 2002. A review of the literature on the worldwide distribution, spread of, and efforts to eradicate the coypu (Myocastor coypus). Wildlife Society Bulletin 30:162-175.

GOSLING, L.M., AND S.J. BAKER. 1989. The eradication of muskrats and coypus from Britain. Biological Journal of the Linnean Society 38:39-51.

LEBLANC, D.J. 1994. Nutria. Pages B71-B80 in R.M. Timm, editor. Prevention and control of wildlife damage. University of Nebraska, Cooperative Extension, Lincoln, NE, USA. MACH, J.J. 2002. Nutria control in Louisiana. Proceedings of the Vertebrate Pest Conference 20:32-39.

SCHITOSKEY, F. JR., J. EVANS, AND G.K. LAVOIE. 1972. Status and control of nutria in California. Proceedings of the Vertebrate Pest Conference 5:15-17.