Abstract: The paper describes the use of the drugs Zoletil® and etorphine for the immobilization of walrus (Odobenus rosmarus rosmarus) for attachment of satellite telemetry equipment. Three animals weighing approximately 1,500 kg each were injected intramuscularly with Zoletil® at a dose between 1.4 and 2.2 mg/kg. One walrus died while the two others were adequately restrained. The induction time was between 14 and 29 minutes and the effect lasted for 75-220 min.
Thirty-eight animals of weight 900-1,500 kg were darted intramuscularly with etorphine at a dose between 3.3 and 8 mg/kg. Thirty-six were immobilized although one died later. The induction time for etorphine was two to ten minutes. The action of this drug was terminated with an injection of the antidote di-prenorphine.
The use of etorphine was accompanied by convulsive movements and apnoea while Zoletil® produced a gradual and smooth entry into and withdrawal from immobilization.