Field Anesthesia of American Martens Using Isoflurane

Isoflurane was used in the field for the immobilization and attachment of radio collars on American martens (Martes americana) (n=108 trials on 91 animals). Martens were captured in Tomahawk live traps and the traps were placed in a plexiglass box for induction with isoflurane. Martens were given 3 ml (78 trials) or 4 ml (30 trials) of isoflurane, a dose that produced induction in 93 trials. A second dose (2 ml) was needed to reach anesthesia in 15 trials. Induction time after the first dose did not differ between doses, sexes, and age classes (99 ± 5sec [SE], range=33–288 sec, n=98). Recovery time for animals receiving a single dose was similar for 3 or 4 ml doses, males or females, and juveniles or adults (215 ± 17 sec, range=30–580 sec, n=62). Only 1 animal died while being handled. Based on telemetry data, ≥82% of the collared animals that we released survived >30 days after anesthesia. During this period, most mortalities that may have been associated with handling and collaring (6 cases) involved smaller animals and did not appear to be related to chemical anesthesia. We conclude that isoflurane is a safe and efficient drug for immobilizing marten with simple equipment when a short handling time (2–3 min) is required.