A live trap model and field trial of a nutria (Rodentia) multiple capture trap

Abstract

, also known as coypu) arelarge semi-aquatic rodents native to South America. Thespecies was first introduced to the United States in 1899for the establishment of a fur farm in California. Sincethen, accidental and intentional releases have permittednutria to become established in wetlands in at least 15states (Carter and Leonard 2002). Today, nutria are animportant resource for the Louisiana fur industry. Despitethis economic advantage, nutria can be detrimental to anarea. Burrowing and foraging by nutria often inflictseveredamage and can be devastating to native vegetation andcrops (LeBlanc 1994). Nutria are recognized as a con-tributing factor in the decline of the native Louisianacoastal marsh (Grace and Ford 1996, Evers et al. 1998).Management plans to control nutria impacts typicallyinvolve population reduction or eradication (Gosling andBaker 1989). At present, public hunting and trapping,encouraged by an incentive payment program, are theprimary approaches used to reduce overabundant pop-ulations in Louisiana. Alternative tools, however, includ-ing toxicants and attractants used to increasing trappingsuccess, need to be assessed for possible use (GenesisLaboratories, Inc. 2002, Nolte et al. 2004).One possible method that could increase nutria cap-ture rates would be a multiple capture trap (MCT). Tra-ditional control methods have involved either single-setleg-hold traps or shooting of individual nutria. Bothmeth-ods are quite labor intensive per nutria collected. Addi-tionally, leg-hold traps, toxicants, and shooting cannotbeused in many urban-suburban settings because of non-target hazards to children, pets, livestock, and protectedwildlife. An effective multiple capture trap could reducethe amount of effort required to capture multiple animalsand reduce non-target animal losses. For populationmanagement purposes, it is also important that an MCTis able to capture target animals of both sexes and bothjuvenile and adult animals. The MCT would also be usefulto capture nutria for research purposes with less chanceof injury than the use of leg-hold traps.This study evaluated one MCT in two different config-urations with two different types of bait. This field studywas conducted on the Mandalay National WildlifeRefugein Terrebonne Parish, southeastern Louisiana. The refugewas approximately 97 km southwest of New Orleans andencompassed 1700 ha. The area was comprised offreshwater marsh and bald cypress (