Estimating body mass of sperm whales from aerial photographs

Glarou, Maria; Gero, Shane; Frantzis, Alexandros; Brotons, José María; Vivier, Fabien; Alexiadou, Paraskevi; Cerdà, Margalida; Pirotta, Enrico; Christiansen, Fredrik

doi:10.1111/mms.12982

Cited by 9 publications

(13 citation statements)

References 76 publications

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“…Arctocephalus pusillus [40,56,57] Group size estimation Sousa sahulensis [58] Scarring assessment Megaptera novaeangliae, Balaenoptera musculus, Balaenoptera physalus [59] Photogrammetry Megaptera novaeangliae [60] Megaptera novaeangliae, Balaenoptera musculus, B. physalus, B. edeni, B. bonaerensis, B. borealis [24,25] Eschrichtius robustus [26,27] Physeter macrocephalus [61] Globicephala macrorhynchus [62] Orcaella heinsohni, Sousa sahulensis [63] Trichechus manatus [64] Behavioural study Phocoena phocoena [65] Ursus maritimus [33][34][35] DJI Phantom 4 Pro V2.0…”

Section: Phoca Vitulina [55]mentioning

confidence: 99%

“…Megaptera novaeangliae [81,82] Eubalaena australis [83][84][85][86][87][88][89] Eschrichtius robustus [90] Physeter macrocephalus [61,91] Globicephala macrorhynchus [62] Phocoena phocoena [92] Behavioural study Eubalaena glacialis, Megaptera novaeangliae [93] DJI Inspire 2…”

Section: Photogrammetrymentioning

confidence: 99%

“…Drone-based photogrammetric studies have assessed the body length of killer whales (Orcinus orca) [119], sperm whales (Physeter macrocephalus) [91], and several species from the family Balaenopteridae [24,25,84,[116][117][118]140], as well as other parameters such as the dorsal surface area [26,44,81,112] or total body volume [72,82,[85][86][87][88]90,96], which have been used to estimate the body condition. Photogrammetric studies assessing body volume and body condition have been widely applied for baleen whale species [23,26,27,44,60,72,[81][82][83][85][86][87][88]90,112,141] and medium and large odontocetes [61,62,96,[120][121][122]. However, they have also been shown to be feasible and reliable for smaller marine mammals such as dolphins [63,126], porpoises…”

Section: Photogrammetrymentioning

confidence: 99%

“…In addition to estimating body condition, morphometric measurements from UAVs can be useful for multiple purposes. Volumetric estimates obtained through photogrammetry provide valuable information to accurately estimate body mass in both cetaceans [61,89] and pinnipeds [97,129]. For the latter, body mass obtained through UAV-based photogrammetry has been used to determine the appropriate dosages of drugs necessary to anaesthetize animals for capture-based methodologies [115].…”

Section: Photogrammetrymentioning

confidence: 99%

See 3 more Smart Citations

Unmanned Aerial Vehicles (UAVs) in Marine Mammal Research: A Review of Current Applications and Challenges

Álvarez-González,

Suarez-Bregua,

Pierce

et al. 2023

Drones

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Research on the ecology and biology of marine mammal populations is necessary to understand ecosystem dynamics and to support conservation management. Emerging monitoring tools and instruments offer the opportunity to obtain such information in an affordable and effective way. In recent years, unmanned aerial vehicles (UAVs) have become an important tool in the study of marine mammals. Here, we reviewed 169 research articles using UAVs to study marine mammals, published up until December 2022. The goals of these studies included estimating the number of individuals in populations and groups via photo-identification, determining biometrics and body condition through photogrammetry, collecting blow samples, and studying behavioural patterns. UAVs can be a valuable, non-invasive, and useful tool for a wide range of applications in marine mammal research. However, it is important to consider some limitations of this technology, mainly associated with autonomy, resistance to the marine environment, and data processing time, which could probably be overcome in the near future.

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Section: Phoca Vitulina [55]mentioning

confidence: 99%

Section: Photogrammetrymentioning

confidence: 99%

Section: Photogrammetrymentioning

confidence: 99%

Section: Photogrammetrymentioning

confidence: 99%

See 2 more Smart Citations

Unmanned Aerial Vehicles (UAVs) in Marine Mammal Research: A Review of Current Applications and Challenges

Álvarez-González,

Suarez-Bregua,

Pierce

et al. 2023

Drones

View full text Add to dashboard Cite

show abstract

“…The use of drones has resulted in increased animal welfare standards in some areas of research, for example by replacing lethal methods such as estimating the mass of whales (Glarou et al, 2023) and often allowing research to be conducted in a less invasive way than if researchers had to approach the study animals closely from a boat (which may have more potential for disturbance and harm than a drone). Given that drones are a relatively new research tool, the ethical issues surrounding their use are still being evaluated (Kannan and Ranganathan, 2020).…”

Section: Other Case Studiesmentioning

confidence: 99%

Ethical standards for research on marine mammals

Papastavrou¹,

Ryan²

2023

Research Ethics

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Conducting marine mammal research can raise several important ethical issues. For example, the continuation of whaling for commercial purposes despite the international moratorium provides opportunities for scientists to obtain data and tissue samples. In 2021 we analysed 35 peer-reviewed papers reporting research based on collaborations with Icelandic whalers. Results highlighted little consideration or understanding of the legal and ethical issues associated with the deliberate killing of whales amongst those researchers, funding bodies, universities and journals involved. Ethical statements were rarely provided. Those that were written were incomplete. Whilst research using whaling data may seem acceptable to some, it often becomes hard to justify when subject to scrutiny by the media and the public. Thus, there is a particular danger of reputational harm for early career researchers who may become unwittingly involved in such activities. Here we also consider the broader variety of ethical issues raised by non-lethal research (both historical and recent) on marine mammals including tagging and biopsy. We discuss instances where study animals were harmed or even killed and where the public mistook tags for harpoons. Without clear guidelines, reviewers and journal editors are put in an impossible position when considering whether to reject papers on ethical grounds. We propose that for such studies, universities, funders, journals, and permit issuers must require ethical assessments and that journals more effectively implement their existing policies on publishing ethical statements. The professional marine mammal societies need to work together to produce modern ethical guidance. Such guidance should require transparency in the provenance of data and samples while including advice on law, welfare issues, involvement of local scientists, and offshoring. Furthermore, it should require appraisal of and justification for the absolute necessity of invasive procedures. As is already the case in biomedical disciplines, ethical statements should be required in marine mammal science.

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Approaching a population‐level assessment of body size in pinnipeds using drones, an early warning of environmental degradation

Carroll,

Infantes,

Pagan

et al. 2024

Remote Sens Ecol Conserv

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Body mass is a fundamental indicator of animal health closely linked to survival and reproductive success. Systematic assessment of body mass for a large proportion of a population can allow early detection of changes likely to impact population growth, facilitating responsive management and a mechanistic understanding of ecological trends. One challenge with integrating body mass assessment into monitoring is sampling enough animals to detect trends and account for individual variation. Harbour seals (Phoca vitulina) are philopatric marine mammals responsive to regional environmental changes, resulting in their use as an indicator species. We present a novel method for the non‐invasive and semi‐automatic assessment of harbour seal body condition, using unoccupied aerial vehicles (UAVs/drones). Morphological parameters are automatically measured in georeferenced images and used to estimate volume, which is then translated to estimated mass. Remote observations of known individuals are utilized to calibrate the method. We achieve a high level of accuracy (mean absolute error of 4.5 kg or 10.5% for all seals and 3.2 kg or 12.7% for pups‐of‐the‐year). We systematically apply the method to wild seals during the Spring pupping season and Autumn over 2 years, achieving a near‐population‐level assessment for pups on land (82.5% measured). With reference to previous mark‐recapture work linking Autumn pup weights to survival, we estimate mean expected probability of over‐winter survival (mean = 0.89, standard deviation = 0.08). This work marks a significant step forward for the non‐invasive assessment of body condition in pinnipeds and could provide daily estimates of body mass for thousands of individuals. It can act as an early warning for deteriorating environmental conditions and be utilized as an integrative tool for wildlife monitoring. It also enables estimation of yearly variation in demographic rates which can be utilized in parameterizing models of population growth with relevance for conservation and evolutionary biology.

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Estimating body mass of sperm whales from aerial photographs

Cited by 9 publications

References 76 publications

Unmanned Aerial Vehicles (UAVs) in Marine Mammal Research: A Review of Current Applications and Challenges

Unmanned Aerial Vehicles (UAVs) in Marine Mammal Research: A Review of Current Applications and Challenges

Ethical standards for research on marine mammals

Approaching a population‐level assessment of body size in pinnipeds using drones, an early warning of environmental degradation

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