Browsing by Author "Hinton B"

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    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 KA
    Empirical 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.
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    Isotopic Niche Analysis of Long-Finned Pilot Whales (Globicephala melas edwardii) in Aotearoa New Zealand Waters
    (MDPI (Basel, Switzerland), 2022-09-28) Hinton B; Stockin KA; Bury SJ; Peters KJ; Betty EL; Calizza E; Careddu G; Costantini ML
    The quantification of a species' trophic niche is important to understand the species ecology and its interactions with the ecosystem it resides in. Despite the high frequency of long-finned pilot whale (Globicephala melas edwardii) strandings on the Aotearoa New Zealand coast, their trophic niche remains poorly understood. To assess the isotopic niche of G. m. edwardii within New Zealand, ontogenetic (sex, total body length, age, maturity status, reproductive group) and spatiotemporal (stranding location, stranding event, and stranding year) variation were investigated. Stable isotopes of carbon (δ13C) and nitrogen (δ15N) were examined from skin samples of 125 G. m. edwardii (67 females and 58 males) collected at mass-stranding events at Onetahua Farewell Spit in 2009 (n = 20), 2011 (n = 20), 2014 (n = 27) and 2017 (n = 20) and at Rakiura Stewart Island in 2010 (n = 19) and 2011 (n = 19). Variations in δ34S values were examined for a subset of 36 individuals. General additive models revealed that stranding event was the strongest predictor for δ13C and δ15N values, whilst sex was the strongest predictor of δ34S isotopic values. Although similar within years, δ13C values were lower in 2014 and 2017 compared to all other years. Furthermore, δ15N values were higher within Farewell Spit 2017 compared to any other stranding event. This suggests that the individuals stranded in Farewell Spit in 2017 may have been feeding at a higher trophic level, or that the nitrogen baseline may have been higher in 2017 than in other years. Spatiotemporal differences explained isotopic variation of G. m. edwardii in New Zealand waters better than ontogenetic factors.
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    Too Close for Comfort? Isotopic Niche Segregation in New Zealand's Odontocetes
    (MDPI (Basel, Switzerland), 2022-08-05) Peters KJ; Bury SJ; Hinton B; Betty EL; Casano-Bally D; Parra GJ; Stockin KA; Calizza E; Careddu G; Costantini ML
    Species occurring in sympatry and relying on similar and limited resources may partition resource use to avoid overlap and interspecific competition. Aotearoa, New Zealand hosts an extraordinarily rich marine megafauna, including 50% of the world's cetacean species. In this study, we used carbon and nitrogen stable isotopes as ecological tracers to investigate isotopic niche overlap between 21 odontocete (toothed whale) species inhabiting neritic, mesopelagic, and bathypelagic waters. Results showed a clear niche separation for the bathypelagic Gray's beaked whales (Mesoplodon grayi) and sperm whales (Physeter macrocephalus), but high isotopic niche overlap and potential interspecific competition for neritic and mesopelagic species. For these species, competition could be reduced via temporal or finer-scale spatial segregation or differences in foraging behaviour. This study represents the first insights into the coexistence of odontocetes in a biodiverse hotspot. The data presented here provide a critical baseline to a system already ongoing ecosystem change via ocean warming and subsequent effects on prey abundance and distributions.