Veterinary Management of Marine Otters (Lontra felina) in Ecological Studies in Chile

The marine otter (Lontra felina) is a poorly studied South American otter of conservation concern. Between 2004 and 2006 as part of radiotelemetry, genetic and veterinary studies, 16 marine otters (10 males and six females), with an average body mass of 3.8 ± 0.3 kg, were trapped in the coast of Central and South Chile. Twenty anaesthetic procedures were evaluated, including chemical immobilizations and anaesthesia for surgical radiotransmitter implantations. We used an intramuscular anaesthetic combination of ketamine 5 mg/kg and medetomidine 50 μg/kg. Minor complications included mild hypothermia and hypoxemia. After 47 ± 10 min, anaesthesia was antagonized with atipamezole 236 ± 38 μg/kg i.m. Full anaesthetic recovery was achieved at 12.0 ± 6.2 min. Six otters (three males and three females) were subjected to surgical radiotransmitter placement through a ventral midline celiotomy. These individuals were housed in a quarantine room in wire-mesh cages (0.9 m long × 0.4 m wide × 0.48 m high), joined with a polyvinyl chloride pipe that served as den (1 m long × 0.4 m diameter). While in captivity, diet consisted on fresh silverside fish (Odontesthes regia) plus several local crab and fish species. During their acclimation period prior to surgery, these individuals received a captivity protocol which included the administration of enrofloxacin, ketoprofen, ivermectin and vitamin supplements. Three otters died in captivity, and severe and moderate ulcerative gastritis was diagnosed at the post-mortem examination. None of the operated otters had surgical complications, and full wound healing was completed by 13 ± 3 days, time when the animals were released. During monitoring by radiotelemetry otters became established in their home ranges.