Field techniques for handling, anaesthetising and fitting radio-transmitters to Eurasian otters (Lutra lutra)

Abstract

Practical issues for radio-tracking studies of otters (Lutra lutra) include their sensitivity to stress, their sensitivity to certain anaesthetic regimes and their unsuitability for standard collar mounted radio-transmitters. We examined the practicability of various field techniques for overcoming these issues in east and south east Ireland from April 2005 to July 2006. Thirty-four highly-stressed otters were restrained with ketamine and midazolam within minutes of capture, to fit externally-mounted transmitters or to transfer them to transport boxes. Eleven otters were fitted with harness mounted radio-transmitters, 2 were fitted with glued-on radio-transmitters and 15 were surgically implanted with intra-abdominal radio-transmitters in the field. The intra-abdominal transmitters were implanted under isoflurane anaesthesia within an hour of initial sedation. We experienced no complications with this anaesthetic regime. The abdominal cavity was accessed by a lateral approach. All surgeries were successful and we recorded no serious post-operative complications. The implantation procedure lasted less than 3 hours from capture to release such that almost all animals stayed within their territories, and pups were not abandoned. However, following their release, animals were sensitive to directed disturbance and could easily be forced to disperse.

Short Note: Tagging Giant Otters (Pteronura brasiliensis) (Carnivora, Mustelidae) for Radio-Telemetry Studies

“…Tagged individuals were visually observed after release, and we observed no impediments to the giant otters, physically or behaviorally, because of the implant, supporting the results also obtained by Ó Neill et al (2008) for the Eurasian otter. The giant otters did not seem to care about the incision site; there was no hemorrhage; and the skin suture did not become damaged or infected.…”

“…The expertise required to tag individuals for telemetry is often underestimated (Ebner, 2009). Otters are unsuited to standard collar-mounted transmitters due to the similar circumference between their neck and head (Ó Neill et al, 2008). In the case of the social giant otters, a collar would likely be easily removed by the radio-tagged animal or by other members of its group during their extensive grooming behavior.…”

A Low-Cost GPS GSM/GPRS Telemetry System: Performance in Stationary Field Tests and Preliminary Data on Wild Otters (Lutra lutra)

“…Harnesses seem to be the most reliable alternative for the application of GPS on otters, to date. In fact, they have been already used on otters, and, although some concerns regarding animal welfare and possible risks exist [14] , [35] , [38] , no significant events are reported in the cited studies.…”

Ranging behaviour and socio-biology of Eurasian otters (Lutra lutra) on lowland mesotrophic river systems

“…Details of the trapping and tagging program have been described in detail elsewhere (Ó Néill et al 2007(Ó Néill et al , 2008. The trapping technique yielded a remarkably high trapping rate of 8.4 trap-nights per otter, or 1.7 (SD=0.9) nights per capture at successful sites.…”