Disentanglement of Cape fur seals (Arctocephalus pusillus pusillus) with reversible medetomidinemidazolam-butorphanol

Authors

  • Brett R Gardner Zoos Victoria
  • Brandon Spolander Aquavet Africa
  • S. Mduduzi Seakamela Fisheries and Environment
  • Steven A McCue Fisheries and Environment
  • Pieter G.H Kotze Fisheries and Environment
  • Maryke Musson Two Oceans Aquarium

Abstract

Anaesthesia in pinnipeds is considered a much higher risk than in most terrestrial mammals because of their frequent proximity to water and physiological and anatomical adaptations related to diving, which also influence their anaesthesia management. Anaesthetising and immobilising entangled seals does not allow for selection of animals that are at a safe distance from the water’s edge. Medetomidine-midazolam-butorphanol (MMB) sedation was trialled on eight entangled Cape fur seals (CFS) (Arctocephalus pusillus pusillus) to determine if it was safe to use on animals that entered the water post-darting. The MMB was given at an estimated dose of 0.03 mg/kg, 0.2 mg/kg and 0.2 mg/kg, respectively, via remote darting. Sedation was reversed with intramuscular atipamezole (0.15 mg/kg) and naltrexone (0.4 mg/kg) to antagonise the effects of medetomidine and butorphanol, respectively. Moderate sedation was achieved in six animals. Six of the animals entered the water after being darted. There was a single mortality and a single animal that was too lightly sedated for capture. The preliminary results indicate that MMB produces suitable sedation for disentanglement of CFS. Additionally, MMB might be suitable for application to field-based biological research. Keywords: reversible anaesthesia; immobilisation; Cape fur seal; medetomidine; midazolam; butorphanol; disentanglement; atipamezole; naltrexone; Arctocephalus pusillus pusillus.

Author Biographies

Brett R Gardner, Zoos Victoria

Werribee Open Range Veterinary Hospital, Zoos Victoria, Werribee, Australia

Brandon Spolander, Aquavet Africa

Aquavet Africa, Hermanus, South Africa

S. Mduduzi Seakamela, Fisheries and Environment

Department of Forestry and Fisheries, Department of Forestry, Fisheries and Environment, Cape Town,
South Africa

Steven A McCue, Fisheries and Environment

Department of Forestry and Fisheries, Department of Forestry, Fisheries and Environment, Cape Town,
South Africa

Pieter G.H Kotze, Fisheries and Environment

Department of Forestry and Fisheries, Department of Forestry, Fisheries and Environment, Cape Town,
South Africa

Maryke Musson, Two Oceans Aquarium

Department of Education Foundation, Two Oceans Aquarium, Cape Town, South Africa

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Published

2021-12-09

Issue

Section

Original Research