Journal Articles
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Item A contribution to the anatomy of two rare cetacean species: The hourglass dolphin (Cephalorhynchus cruciger) and the spectacled porpoise (Phocoena dioptrica)(Wiley Periodicals LLC on behalf of American Association for Anatomy, 2025-10-22) Graïc J-M; Gerussi T; Cozzi B; Boys RM; Kot BCW; Perrott MR; Fleury K; Chung TYT; Tsui HCL; Burns E; Webster T; Hunter S; Betty EL; Howarth O; Loch C; White S; Dawson S; Rayment W; Cole R; Cox D; Waterhouse T; Hendriks H; van Helden A; Johnstone M; Stewart RO; Fordyce RE; Stockin KAThe anatomical description of the hourglass dolphin (Cephalorhynchus cruciger) and the spectacled porpoise (Phocoena dioptrica) remains largely unexplored, due to limited specimen availability and preservation challenges. This study employed digital imaging techniques, conventional histology, and computed tomography to provide visualization of anatomical structures for a detailed analysis. We present a comprehensive analysis of the gross macroscopical and microscopical morphology of two hourglass dolphins and four spectacled porpoises. Morphometric measurements and skeletal characteristics aligned with the literature, while internal anatomy (organs and systems) was similar to other odontocetes. Precise and consistent lung measurements were challenging; qualitative assessments indicated relatively large lungs with respect to body size. The spectacled porpoise dorsal fin was uniquely large with a well-developed blood supply; this is hypothesized to act as a thermoregulatory window, though it may also play a role in sexual display in the case of males. Overall, this study provides new data on the anatomy of the hourglass dolphin and spectacled porpoise, contributing insights that may influence future research on these rare species. The findings highlight the importance of anatomical studies as a basis for explaining evolutionary relationships within cetaceans and their ecological roles in the Southern Ocean ecosystems.Item A contribution to the anatomy of two rare cetacean species: the hourglass dolphin (Lagenorhynchus cruciger) and the spectacled porpoise (Phocoena dioptrica)(2025-03-26) Graïc J-M; Gerussi T; Cozzi B; Boys RM; Kot BCW; Perrott MR; Fleury K; Chung TYT; Tsui HCL; Burns E; Webster T; Hunter S; Betty EL; Howarth O; Loch C; White S; Dawson S; Rayment W; Cole R; Cox D; Waterhouse T; Hendriks H; van Helden A; Johnstone M; Stewart RO; Fordyce RE; Stockin KAItem Using post-mortem computed tomography to identify traumatic cranial lesions in small stranded odontocetes euthanised via ballistics(Taylor and Francis Group on behalf of the New Zealand Veterinary Association, 2025-07-29) Boys RM; Stewart RO; Kot BCW; Lye G; Beausoleil NJ; Stockin KAAims: To describe the pathophysiology caused by ballistics applied to the head of stranded cetaceans that required euthanasia and use this information to infer the likely welfare implications of these real-life euthanasia events. Methods: Post-mortem computed tomography (PMCT) imaging was conducted on six cetacean carcasses of five different species that were submitted for dissection following ballistics euthanasia. No animals were euthanised for the purpose of this study. All data were collected opportunistically at stranding events where euthanasia was a priori deemed necessary by the Department of Conservation (DOC) in partnership with indigenous Māori (iwi). The cranial damage assessed included osseous lesions at entry and exit wounds, intracranial bone fractures and intracranial projectile fragments. Potential welfare implications were inferred based on the likelihood of instantaneous insensibility occurring due to direct physical disruption to the brainstem. Additionally, basic stranding data were collected from DOC incident reports including whether animals were refloated prior to the decision for euthanasia. We also gathered information from the marksperson involved on how the ballistics method was employed, equipment used, and animal insensibility assessed at each stranding event. Results: PMCT results suggest that two animals were likely instantaneously insensible, three had a moderate chance of being instantly insensible and one had a low chance of instantaneous insensibility. In one case, the marksperson reported a faster time to insensibility/death than was judged likely to have occurred from PMCT. In only two cases were the criteria for verifying insensibility reported as being checked. The likelihood of instantaneous insensibility occurring was affected by shot placement/aim and characteristics of the projectile used. Conclusions: Euthanasia is a critical option for severely compromised cetaceans. While most animals examined were probably rapidly insensible following shooting, cranial trauma and thus confidence in the efficacy of ballistics seemed to vary with shot placement, aim, equipment and cranial anatomy. Clinical relevance: Verification of insensibility immediately following shooting, by assessing reflex responses as recommended, is crucial to ensure humane emergency management. PMCT provides an effective non-destructive tool to validate field methods for assessing the efficacy of euthanasia.Item Out of habitat marine mammals – Identification, causes, and management recommendations(Elsevier Ltd, 2025-07) Nunny L; Bossley M; Boys RM; Brakes P; Genov T; Parsons ECM; Peters KJ; Rose NA; Simeone CA; Stockin KA; Vail CS; van der Linde K; Visser IN; Simmonds MPAn out of habitat (OOH) marine mammal is an individual found outside of their natural range, e.g., an Atlantic walrus (Odobenus rosmarus rosmarus) along the coastline of mainland Europe, or an individual within their natural range in habitat that is not optimal for their health or survival due to a lack of suitable conditions and/or because of potential conflict with humans. As the number of OOH marine mammals appears to be increasing, and following on from two international workshops, here we define what constitutes an OOH marine mammal and provide a detailed assessment of potential drivers. Climate change, habitat loss and/or degradation, disturbance, changes in prey distribution, and morbidity may all be reasons for a marine mammal being OOH. Appropriate management of OOH marine mammals is considered. This may simply involve monitoring to better understand the situation, to protect the welfare of the animal(s) and to ensure that members of the public are kept safe. However, on occasion, further intervention may be required, such as providing safe areas for the OOH marine mammal(s), encouraging the animal(s) to move, capture and translocation, or euthanasia. Regardless of the action taken, educating and communicating with the public are key elements of OOH marine mammal management. Lessons can be learned from human-wildlife conflict and rewilding scenarios. The potential for OOH marine mammals to be pioneers seeking new habitat, contributing to species resilience in the face of rapidly changing environments, and how to include them in conservation legislation and management planning are considered.Item Ethological and procedural assessment of ballistics euthanasia for stranded cetaceans(Elsevier B.V., 2025-02-12) Boys RM; Beausoleil NJ; Stockin KAEuthanasia may be necessary at cetacean stranding events to end suffering. To ensure a humane death, verification of unconsciousness must be undertaken following application of the killing method. However, only limited information is reported on individual euthanasia events, including how unconsciousness and/or death is assessed. Here, we describe current practices for euthanising stranded cetaceans in New Zealand by analysing video footage of fourteen ballistics events involving various species. Specifically, we detail the ballistics procedures applied and the behavioural responses of the animals. Additionally, we sought to understand how animal unconsciousness was evaluated following each event by surveying the personnel involved. Video recordings ranged in length from 25 to 480 s after the initial shot and involved 14 cetaceans: one Cuvier's beaked whale, one pygmy sperm whale, one bottlenose dolphin, four pilot whales and seven false killer whales. Unconsciousness criteria were typically not observed being verified in the videos analysed, despite markspersons stating that death occurred in < 1 minute for most animals. Number of shots applied to an animal ranged from 1–3. Key behaviours indicative of unconsciousness included a continuously slack lower jaw and epaxial muscle relaxation. Based on behavioural observations, 66.7 % of animals for which an estimate could be made (n = 12) were likely unconscious within 30 s of the initial shot; half of these were likely unconscious within 10 s. The remaining animals appeared conscious for 30 s after the initial shot, and half of these were likely still conscious after one minute. Ten animals displayed post-shot behaviours suggestive of voluntary control, including tail lifting, beyond the point of presumed death reported by markspersons. The lack of verification of unconsciousness in most animals (12/14) hinders our ability to understand how these behaviours may correlate with awareness and thus welfare impacts of shooting. While the application of ballistics appeared to follow current national recommendations, mandated procedures for verifying death were rarely observed. We recommend exploring the reasons for this finding, to ensure that such procedures are appropriately undertaken, and welfare compromise minimised.Item Evaluation of ballistics euthanasia applied to stranded cetaceans using ethological and post-mortem computed tomography assessment(Springer Nature, 2024-09-17) Boys RM; Kot BCW; Lye G; Beausoleil NJ; Hunter S; Stockin KADebilitated 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.Item Assessing animal welfare during a stranding of pygmy killer whales (Feresa attenuata)(John Wiley and Sons, Inc., 2023-10-01) Boys RM; Beausoleil NJ; Hunter S; Betty EL; Hinton B; Stockin KAEmpirical assessment of cetacean welfare to inform stranding interventions is lacking. Here, potential welfare indicators are described for two stranded pygmy killer whales (Feresa attenuata), along with euthanasia procedures and pathology of potential relevance. The animals were filmed for 3.5 and 1.5 hr, respectively, allowing assessment of 19 indicators, including animal behaviors and human interventions. Eight interventions and 19 animal behaviors were identified; 17 and 11 behaviors were displayed by animal 1 and 2, respectively. Examination of ballistics euthanasia revealed atypical projectile placement and characterized animal behavioral responses, but welfare implications could not be assessed as insensibility was not verified in-field. Pulmonary edema and renal degeneration were documented in both animals; differential etiologies include ischemia–reperfusion, shock, and/or myopathy. Potential relationships among histopathology and welfare indicators are explored to infer affective experiences. For example, simultaneous head-lifting with respiration increased over time which, alongside pulmonary edema, suggests these animals experienced breathlessness. Other likely affective states include fatigue and discomfort; there are insufficient data to estimate the intensity or duration of these experiences or to provide an overall welfare grade/score. Further data are required to validate the proposed welfare indicators and to progress development of holistic approaches to welfare assessment at cetacean strandings.Item Deathly Silent: Exploring the Global Lack of Data Relating to Stranded Cetacean Euthanasia(MDPI (Basel, Switzerland), 2021-05-19) Boys RM; Beausoleil NJ; Betty EL; Stockin KA; Hopper L; Lambooij EThe compromised state of stranded cetaceans means that euthanasia is often required. However, current knowledge and implementation of euthanasia methods remain highly variable, with limited data on the practicalities and welfare impacts of procedures. This study evaluated the available published data on cetacean euthanasia, highlighting knowledge gaps and providing direction to improve stranded cetacean welfare. A total of 2147 peer-reviewed articles describing marine mammal euthanasia were examined. Of these 3.1% provided details on the method used, with 91% employing chemical methods. Two countries, the United Kingdom (UK) and New Zealand (NZ), provided euthanasia reports to the International Whaling Commission (IWC) between 2007 and 2020. Methods employed were reported for 78.3% and 100% of individual cetaceans euthanised in the UK and NZ, respectively. In the UK, chemical euthanasia was most common (52%), whilst in NZ only ballistics methods were used. Few data were available about time to death/insensibility (TTD); 0.5% of peer-reviewed articles provided TTD, whilst TTD was reported for 35% of individuals in the UK and for 98% in NZ. However, IWC reports lacked detail on how death/insensibility were assessed, with multiple individuals "presumed instantly" killed. Overall, the findings highlight the lack of available information on cetacean euthanasia, and suggest increased data collection and the application of appropriate methods to improve welfare.Item When and how to say goodbye: An analysis of Standard Operating Procedures that guide end-of-life decision-making for stranded cetaceans in Australasia(Elsevier Ltd, 2022-04) Boys RM; Beausoleil NJ; Betty EL; Stockin KAStandard Operating Procedures (SOPs) are tools used to ensure management best practice during emergency incidents including wildlife interventions, such as cetacean strandings. The compromised state of stranded cetaceans means humane end-of-life decisions may be considered, and SOPs frequently guide this process. This study evaluated SOPs for end-of-life decision-making and technically enacting euthanasia of stranded cetaceans across Australasia. The aim was to highlight similarities and differences in management and explore directions to improve stranded cetacean welfare. SOPs were requested from the eight government authorities across Australia and New Zealand. All SOPs were evaluated for decision-making criteria, yielding 29 parameters for the implementation of end-of-life decisions. Euthanasia and palliative care were options for end-of-life, with palliative care recommended when euthanasia was not feasible or presented human safety risks. Three euthanasia methods were recommended. Ballistics was recommended in seven SOPs, chemicals in five and explosives in three SOPs. Variability existed in the exact procedures and equipment recommended in all three methods. Additionally, only five SOPs provided criteria for verifying death, while only two recommended time-to-death be recorded, hindering evaluation of the welfare impacts of end-of-life decisions and euthanasia procedures. Our findings highlight the need for detailed guidance and consistency in end-of-life decisions and euthanasia techniques to ensure reliable welfare outcomes. Systematic, standardised data collection at euthanasia events across regions is required to facilitate assessment of welfare impacts and develop evidence-based recommendations. International collaboration is key to developing objective criteria necessary to ensure consistent guidance for end-of-life decisions.Item Increasing the Awareness of Animal Welfare Science in Marine Mammal Conservation: Addressing Language, Translation and Reception Issues(MDPI (Basel, Switzerland), 2021-05-28) Clegg ILK; Boys RM; Stockin KA; Gili C; Centelleghe CIntegrating welfare principles into conservation strategy is an emerging synthesis that encourages consideration of individual animals' quality of life in research, policies and law. However, these principles have gained limited traction in marine compared to terrestrial animal conservation. This manuscript investigates several factors that may be contributing to this disparity. In order to gauge current understanding of animal welfare science principles by marine mammal researchers and other stakeholders, a "Welfare in the Wild" workshop was convened at the 32nd European Cetacean Society conference (La Spezia, Italy, April 2018). The workshop was attended by 30 participants who completed pre- and post-workshop surveys on animal welfare principles. The survey results highlight a range of different views about exactly what animal welfare science is and how it can be applied to marine mammals. Specifically, participants' definitions appeared to vary depending on the type of employment or research they engaged in, indicating a need for an interdisciplinary common language. Secondly, we analysed the peer-reviewed literature in order to ascertain where marine mammal publications exploring welfare were being published. From 1950 to July 2020, a total of 299 articles featured both marine mammal taxa (one or more) and the word welfare in the title, abstract or keywords. This represents just 0.96% of the total peer-reviewed published papers on marine mammal taxa (n = 31,221) during the same period. When examining articles published within "Welfare and Ethics" (n = 6133) and "Aquatic-focused" (n = 139,352) journals, just 1.2% (n = 71) and 0.04% (n = 57) of articles, respectively, featured the word welfare when examining marine mammals. With the aim of exploring how explicitly including welfare evaluations in marine mammal research and management can benefit conservation outcomes, we framed our workshop and quantitative literature review findings to provide practical solutions to the language, translation and reception issues of this burgeoning cross-disciplinary collaboration.