EUTHANASIA OF LARGE, STRANDED CETACEANS
The euthanasia of large cetaceans is challenging (Blyde and Vogelnest 2008; Gales et al. 2008) because of the need to ensure: a rapid and humane death; methods are acceptable to the public; safety for personnel; experienced and suitably trained personnel; decontamination of sites following chemical euthanasia; no potential for secondary toxicity of scavengers; and removal or disposal of the carcase (Table 46.1).
Both physical and chemical methods are available that overcome many of these challenges. Chemical methods such as the use of opioids and sedatives followed by barbiturates and potassium chloride are useful but also require specialised equipment, suitably trained and experienced personnel and often vast quantities of the chemicals. Harms et al. (2014) describe a euthanasia technique for stranded whales using sedative drugs followed by IC delivery of saturated potassium chloride using customised delivery devices (Fig. 46.2). Sedatives used included various IM combinations of midazolam, diazepam, acepromazine, xylazine and medetomidine. A recommended combination is midazolam 0.05-0.1 mg/kg followed by acepromazine 0.2-1.0 mg/kg +/- butorphanol 0.05 mg/kg followed by xylazine 3-4 mg/kg. All injections are given IM with 10 min intervals between drugs. Potassium chloride (KCl) is then administrated IC or IV at 1-2 mmol/kg. IfTable 46.1. Methods for euthanasia of large stranded cetaceans and the advantages and disadvantages of each
| Method | Advantages | Disadvantages |
| Chemical | Humane Acceptable to public | Requires a veterinarian with cetacean experience Large volumes of drug Specialised needles for IC injection Chemically contaminated carcass requiring disposal |
| Ballistics | Humane Animal must be on land Instant No chemically contaminated carcass requiring disposal | Requires experienced, highly skilled personnel Requires appropriate equipment May not be acceptable to the public Not suitable for animals >6 m |
| Explosives | Humane No chemically contaminated carcass requiring disposal | Requires experienced, highly trained personnel Requires appropriate and specialised equipment Highly controlled and regulated use of explosives May not be acceptable to the public |
| Exsanguination | No need for experienced personnel or specialised equipment No chemically contaminated carcass requiring disposal May be only option when unable to use other methods | Inhumane Not acceptable to the public |
| Benign neglect | No need for experienced personnel or specialised equipment No chemical contaminated carcass requiring disposal May be only option when unable to use other methods | Inhumane Not generally acceptable to the public |
the IC route is used infusion of a local anaesthetic around the needle insertion site is recommended. A 10-m, 14.7-tonne hump-backed whale (Megaptera novaeangliae) was euthanased using 250 g xylazine IM as a sedative followed 90 min later by IC pentobarbitone sodium to effect (D March pers.
comm.). In most cases the doses of sedatives and euthanasia solutions are not calculated, as accuracy and overdosing are not important factors. However, weights of cetaceans if needed can be estimated using the
Fig. 46.2. Customised delivery device for intracardiac delivery of euthanasia solutions in large, stranded cetaceans. Photo: Girius Antanaitis, GA Medical, North Balwyn, Vic, Australia
smartphone App tWhaleScale' available for iOS devices. Coughran et al. (2012) describe a method for euthanasing hump-backed whales using explosives. Firearms have been used for decades to euthanase cetaceans, particularly in commercial and indigenous whale harvesting operations. Hampton et al. (2014) describe and validate a technique using firearms for euthanasing stranded cetaceans. Their recommendation is three shots fired at point blank range behind the blowhole into the brain at a 45° angle using a 0.30 calibre firearm and solid copper-alloy non-deforming projectiles. Other less humane and less acceptable methods include exsanguination by severing the caudal peduncle and benign neglect or palliative care. Although these methods are less preferable, they may be the only options in certain circumstances where there is a lack of resources or in inaccessible or remote locations.
3.