Rapid weight loss in free ranging pygmy killer whales (Feresa attenuata) and the implications for anthropogenic disturbance of odontocetes

Currie, Jens J.; Aswegen, Martin van; Stack, Stephanie H.; West, Kristi L.; Vivier, Fabien; Bejder, Lars

doi:10.1038/s41598-021-87514-2

Cited by 15 publications

(13 citation statements)

References 56 publications

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“…They also provide information on the physical and biological environment that can characterise the prey landscape ( Arranz et al, 2011 ; Goulet et al, 2019 ; McMahon et al, 2019 , 2021 ). Unmanned systems are currently being applied to marine mammal bioenergetics, particularly the use of aerial systems to estimate body condition and growth ( Fearnbach et al, 2018 ; Lemos et al, 2020 ; Aoki et al, 2021 ; Currie et al, 2021 ; Shero et al, 2021 ; Stewart et al, 2021a ; Christiansen et al, 2022 ), and surface and underwater systems to survey prey communities ( Kuhn et al, 2019 ; Benoit-Bird et al, 2020 ). Environmental DNA (eDNA) is a promising emerging tool for addressing questions related to prey landscapes, as it appears able to characterise the distribution and diversity of prey communities ( Visser et al, 2021 ) as well as prey biomass ( Rourke et al, 2022 ).…”

Section: Resultsmentioning

confidence: 99%

Key questions in marine mammal bioenergetics

McHuron

Adamczak

Arnould

et al. 2022

Conservation Physiology

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Bioenergetic approaches are increasingly used to understand how marine mammal populations could be affected by a changing and disturbed aquatic environment. There remain considerable gaps in our knowledge of marine mammal bioenergetics, which hinder the application of bioenergetic studies to inform policy decisions. We conducted a priority-setting exercise to identify high-priority unanswered questions in marine mammal bioenergetics, with an emphasis on questions relevant to conservation and management. Electronic communication and a virtual workshop were used to solicit and collate potential research questions from the marine mammal bioenergetic community. From a final list of 39 questions, 11 were identified as ‘key’ questions because they received votes from at least 50% of survey participants. Key questions included those related to energy intake (prey landscapes, exposure to human activities) and expenditure (field metabolic rate, exposure to human activities, lactation, time-activity budgets), energy allocation priorities, metrics of body condition and relationships with survival and reproductive success and extrapolation of data from one species to another. Existing tools to address key questions include labelled water, animal-borne sensors, mark-resight data from long-term research programs, environmental DNA and unmanned vehicles. Further validation of existing approaches and development of new methodologies are needed to comprehensively address some key questions, particularly for cetaceans. The identification of these key questions can provide a guiding framework to set research priorities, which ultimately may yield more accurate information to inform policies and better conserve marine mammal populations.

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Section: Resultsmentioning

confidence: 99%

Key questions in marine mammal bioenergetics

McHuron

Adamczak

Arnould

et al. 2022

Conservation Physiology

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“…Prior measures of AA and AI from biopsies collected from southern hemisphere humpback whales demonstrated that it was possible to identify fasting and feeding groups in one study (Castrillon et al, 2017) and sex ratios were correlated with blubber biopsy AA measures in another (Druskat Frontiers in Physiology frontiersin.org et al, 2019). To our knowledge, AA and AI have not yet been compared in blubber of biopsied odontocetes although AA and AI values were consistent with drone derived body condition assessments in a limited number of pygmy killer whales involved in a prolonged mass stranding event (Currie et al, 2021). Measurement of blubber AA and AI in biopsies has the potential to serve as a valuable tool for conducting overall body condition assessments in odontocetes.…”

Section: Applicationmentioning

confidence: 87%

Variation in blubber thickness and histology metrics across the body topography of a false killer whale (Pseudorca crassidens)

Phipps

Silva‐Krott

Marchetti³

et al. 2023

Front. Physiol.

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Blubber is a multifunctional tissue essential to the survival of cetaceans. Histological assessment of blubber may be useful in determining odontocete nutritional state but a greater understanding of specific variation across the body is needed. We report on morphological variation of the blubber according to girth axes and sampling planes in a sub-adult male, bycaught false killer whale (Pseudorca crassidens) using metrics of blubber thickness (BT), adipocyte area (AA), and adipocyte index (AI). 48 full depth blubber samples were taken along 6 girth axes at 5 equidistant sampling points on both sides of the body. At these sampling locations BT was recorded, and AA and AI were determined for three distinct blubber layers. Linear mixed effect models were used to assess variation of the blubber across layers and body topography. BT was somewhat non-uniform across the body but was generally thicker in the dorsal region and thinner laterally. AA was greater cranially and AI was greater caudally. The middle and inner layer blubber showed significant differences dorsoventrally with larger AA and smaller AI in the ventral region of the body. Variation of the blubber metrics across the body are indicative of variable functions of the blubber within an individual. Due to the variability observed, we expect that AI of the dynamic inner layer blubber is most informative of overall body condition and that biopsy samples of the outer and middle blubber may still be useful in determining the nutritional status of live false killer whales.

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“…The relationship between body condition and provisioned energy has not been investigated for any odontocete, since it is usually impractical to confirm milk delivery or estimate volume ( Gero and Whitehead, 2007 ). However, aerial photogrammetry has recently been used successfully to quantify changes in body condition during foraging interruption for odontocetes ( Currie et al , 2021 ) and assess how female body condition drives calf development in baleen whales ( Christiansen et al , 2016 , 2018 ). Similar data on calf development and maternal condition could be collected for odontocetes, ideally under both natural and disturbed conditions.…”

Section: Discussionmentioning

confidence: 99%

Modelling the impact of condition-dependent responses and lipid-store availability on the consequences of disturbance in a cetacean

Burslem

Isojunno

Pirotta

et al. 2022

Conservation Physiology

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Lipid-store body condition is fundamental to how animals cope with environmental fluctuations, including anthropogenic change. As it provides an energetic buffer, body condition is expected to influence risk-taking strategies, with both positive and negative relationships between body condition and risk-taking posited in the literature. Individuals in good condition may take more risks due to state-dependent safety (‘ability-based’ explanation), or alternatively fewer risks due to asset protection and reduced need to undertake risky foraging (‘needs-based’ explanation). Such state-dependent responses could drive non-linear impacts of anthropogenic activities through feedback between body condition and behavioural disturbance. Here, we present a simple bioenergetic model that explicitly incorporates hypothetical body condition-dependent response strategies for a cetacean, the sperm whale. The model considered the consequences of state-dependent foraging cessation and availability of wax ester (WE) lipids for calf provisioning and female survival. We found strikingly different consequences of disturbance depending on strategy and WE availability scenarios. Compared with the null strategy, where responses to disturbance were independent of body condition, the needs-based strategy mitigated predicted reductions in provisioning by 10%–13%, while the ability-based strategy exaggerated reductions by 63%–113%. Lower WE availability resulted in more extreme outcomes because energy stores were smaller relative to the daily energy balance. In the 0% availability scenario, while the needs-based strategy reduced deaths by 100%, the ability-based strategy increased them by 335% relative to null and by 56% relative to the same strategy under the 5%–6.7% WE availability scenario. These results highlight that state-dependent disturbance responses and energy store availability could substantially impact the population consequences of disturbance. Our ability to set appropriate precautionary disturbance thresholds therefore requires empirical tests of ability- vs needs-based response modification as a function of body condition and a clearer understanding of energy store availability.

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Rapid weight loss in free ranging pygmy killer whales (Feresa attenuata) and the implications for anthropogenic disturbance of odontocetes

Cited by 15 publications

References 56 publications

Key questions in marine mammal bioenergetics

Key questions in marine mammal bioenergetics

Variation in blubber thickness and histology metrics across the body topography of a false killer whale (Pseudorca crassidens)

Modelling the impact of condition-dependent responses and lipid-store availability on the consequences of disturbance in a cetacean

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