Cetacean Ecology Research Group, College of Sciences, Massey University, Private Bag 102-904, Auckland, New Zealand.
Department of Infectious Diseases and Public Health, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Hong Kong, China.
Vet Res Commun. 2024 Dec;48(6):3989-4006. doi: 10.1007/s11259-024-10537-3. Epub 2024 Sep 17.
Debilitated stranded cetaceans with low survival likelihood, may require euthanasia to avoid further suffering. Euthanasia can involve chemical or physical methods, including ballistics. Ballistics should cause instantaneous, permanent insensibility through brainstem disruption. Despite wide application, there is limited understanding of ballistics-related welfare outcomes. We opportunistically examined behaviour of three maternally-dependent cetaceans following shooting and the related cranial disruption post-mortem using computed tomography (PMCT). Our aim was to understand whether a 'humane death', i.e., euthanasia, was achieved. Each animal was shot using different projectile types: soft non-bonded, solid, and soft bonded. In two animals, insensibility was not immediately assessed following shooting, although both were reported as 'instantaneously insensible'. From our analysis, all animals displayed musculoskeletal responses to shooting, including peduncle stiffening and slack lower jaw, followed by musculature relaxation 24-, 10.3- and 20.8-seconds post-ballistics, respectively. The animal shot with a soft non-bonded projectile also displayed agonal convulsions and tail-lifting for 16-seconds post-shot; these were not observed for solid or soft bonded projectiles. PMCT findings indicated projectile disruption to the brainstem and/or spinal cord likely to cause near-instantaneous insensibility. However, extra-cranial wounding was also evident for the soft non-bonded projectile, highlighting potential for additional welfare compromise. Our results demonstrate that ballistics can achieve a relatively rapid death in young, stranded cetaceans, but careful equipment selection is required. To ensure a humane death, verification of insensibility must be undertaken immediately following shooting. Further studies should be undertaken to improve knowledge of appropriate procedures and equipment for euthanasia, ensuring humane deaths for compromised cetaceans.
衰弱的搁浅鲸目动物生存可能性低，可能需要实施安乐死以避免进一步受苦。安乐死可以采用化学或物理方法，包括弹道。弹道应通过破坏脑干导致瞬间、永久的无知觉。尽管广泛应用，但对与弹道相关的福利结果的理解有限。我们偶然检查了三只依赖母亲的鲸目动物在枪击后的行为，以及死后使用计算机断层扫描（PMCT）检查相关的颅后破坏。我们的目的是了解是否实现了“人道死亡”，即安乐死。每只动物都使用不同的弹丸类型进行射击：软非结合、硬和软结合。在两只动物中，枪击后没有立即评估失去知觉，尽管都被报告为“立即失去知觉”。从我们的分析来看，所有动物在枪击后都表现出肌肉骨骼反应，包括支柱僵硬和下颚松弛，随后在 24 秒、10.3 秒和 20.8 秒后肌肉松弛。被软非结合弹丸射击的动物还在射击后 16 秒出现濒死性抽搐和尾部抬起；在硬弹丸或软结合弹丸射击后没有观察到这些现象。PMCT 结果表明，弹道可能会破坏脑干和/或脊髓，导致近乎瞬间的无知觉。然而，软非结合弹丸也出现了颅外创伤，这突显了潜在的额外福利损害。我们的结果表明，弹道可以使年轻的搁浅鲸目动物相对迅速地死亡，但需要仔细选择设备。为了确保人道死亡，必须在枪击后立即进行知觉丧失的验证。应进行进一步的研究，以提高对适当程序和设备的认识，确保受损的鲸目动物能够人道死亡。
