A surplus no more? Variation in krill availability impacts reproductive rates of Antarctic baleen whales

Global Change Biology, Год журнала: 2023, Номер 29(8), С. 2108 - 2121

Опубликована: Янв. 15, 2023

The krill surplus hypothesis of unlimited prey resources available for Antarctic predators due to commercial whaling in the 20th century has remained largely untested since 1970s. Rapid warming Western Peninsula (WAP) over past 50 years resulted decreased seasonal ice cover and a reduction krill. latter is being exacerbated by fishery region. Despite this, humpback whale populations have increased but may be at threshold growth based on these human-induced changes. Understanding how climate-mediated variation availability influences population dynamics critical focused management conservation actions. Using an 8-year dataset (2013-2020), we show that inter-annual pregnancy rates, as determined from skin-blubber biopsy samples (n = 616), are positively correlated with fluctuations previous year. Pregnancy rates showed significant variability, between 29% 86%. Our results indicate fact limiting affecting reproductive contrast hypothesis. This suggests this whales limitations. As result, continued fishing along WAP, which continue reduce stocks, will likely impact other Humpback sentinel species ecosystem health, changes can provide quantifiable signals environmental change level. findings must considered paramount developing new more restrictive plans marine minimizing negative impacts human activities

Язык: Английский

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

Drones, Год журнала: 2023, Номер 7(11), С. 667 - 667

Опубликована: Ноя. 9, 2023

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

Язык: Английский

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Automated body length and body condition measurements of whales from drone videos for rapid assessment of population health

Marine Mammal Science, Год журнала: 2024, Номер 40(4)

Опубликована: Май 10, 2024

Abstract Monitoring body length and condition of individuals helps determine overall population health assess adaptation to environmental changes. Aerial photogrammetry from drone‐based videos is a valuable method for obtaining measurements cetaceans. However, the laborious manual processing select frames measure animals ultimately delays assessment hinders conservation actions. Here, we apply deep learning methods expedite improve efficiency important morphological whales. We develop two user‐friendly models automatically (1) detect output containing whales (“DeteX”) (2) extract input (“XtraX”). use gray compare versus automated ( n = 86). Our results show reduced times by one‐ninth, while achieving similar accuracy as (mean coefficient variation <5%). also demonstrate how these are adaptable other species identify remaining challenges help further in future. Importantly, tools greatly speed up key data maintaining accuracy, which critical effectively monitoring health.

Язык: Английский

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Whale recovery and the emerging human-wildlife conflict over Antarctic krill

Nature Communications, Год журнала: 2024, Номер 15(1)

Опубликована: Сен. 10, 2024

Язык: Английский

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Assessment of a non-invasive approach to pregnancy diagnosis in gray whales through drone-based photogrammetry and faecal hormone analysis

Royal Society Open Science, Год журнала: 2023, Номер 10(7)

Опубликована: Июль 1, 2023

Knowledge of baleen whales' reproductive physiology is limited and requires long-term individual-based studies innovative tools. We used 6 years individual-level data on the Pacific Coast Feeding Group gray whales to evaluate utility faecal progesterone immunoassays drone-based photogrammetry for pregnancy diagnosis. explored variability in metabolites body morphology relative observed status estimated probability mature females unknown using normal mixture models. Individual had higher concentrations when pregnant than presumed non-pregnant. Yet, at population level, high overlap metabolite occurred between non-pregnant groups, limiting this metric accurate diagnosis whales. Alternatively, width 50% total length (W50) correctly discriminated from individual levels, with accuracy. Application model W50 identified eight additional pregnancies confidence. Our findings highlight non-invasively diagnose group whales, potential improved rates management generally.

Язык: Английский

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Downsizing a heavyweight: factors and methods that revise weight estimates of the giant fossil whale Perucetus colossus

PeerJ, Год журнала: 2024, Номер 12, С. e16978 - e16978

Опубликована: Фев. 29, 2024

Extremes in organismal size have broad interest ecology and evolution because dictates many traits of an organism’s biology. There is particular fascination with identifying upper extremes the largest vertebrates, given challenges difficulties measuring extant extinct candidates for animal all time, such as whales, terrestrial non-avian dinosaurs, marine reptiles. The discovery Perucetus colossus , a giant basilosaurid whale from Eocene Peru, challenged assumptions about based on reconstructions its body weight that exceeded reported values blue whales ( Balaenoptera musculus ). Here we present examination series factors methodological approaches to assess reconstructing including: data sources large cetaceans; fitting published mass estimates outlines; testing assumption isometry between skeletal masses, even extrapolation; examining role pachyostosis reconstructions; addressing method-dependent error rates; comparing known physiological ecological limits living oceanic productivity. We conclude did not exceed today’s whales. Depending methods, estimate weighed 60–70 tons assuming length 17 m. calculated larger potentially much 98–114 at 20 m length, which far less than direct records weights, or 270 ton weights measured by length.

Язык: Английский

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Closing the air gap: the use of drones for studying wildlife ecophysiology

Biological reviews/Biological reviews of the Cambridge Philosophical Society, Год журнала: 2025, Номер unknown

Опубликована: Янв. 17, 2025

ABSTRACT Techniques for non‐invasive sampling of ecophysiological data in wild animals have been developed response to challenges associated with studying captive or using invasive methods. Of these, drones, also known as Unoccupied Aerial Vehicles (UAVs), and their sensors, emerged a promising tool the ecophysiology toolkit. In this review, we synthesise research scoping review on use drones wildlife PRISMA‐SCr checklist identify where efforts focused knowledge gaps remain. We these results explore current best practices provide recommendations future use. 136 studies published since 2010, aided animal body condition morphometrics, kinematics biomechanics, bioenergetics, health (e.g. microbiomes, endocrinology, disease) both aquatic terrestrial environments. Focal taxa are biased towards marine mammals, particularly cetaceans. While conducted globally, is primarily led by institutions based North America, Oceania, Europe. The obtain morphometric through standard colour sensors single camera photogrammetry predominates. such video tracking thermal imaging allowed insights into other aspects ecophysiology, when combined external techniques biologgers. most used commercially available multirotor platforms modification collect samples, integration techniques, multidisciplinary integrate suite remote sensing methods more fully. outline how technological advances will play key role delivery novel improved data. recommend that researchers prepare influx drone‐assisted advancements cross‐institutional collaborations. describe diversify across species environments sources technologies comprehensive results.

Язык: Английский

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Automated extraction of right whale morphometric data from drone aerial photographs

Remote Sensing in Ecology and Conservation, Год журнала: 2025, Номер unknown

Опубликована: Март 10, 2025

Abstract Aerial photogrammetry is a popular non‐invasive tool to measure the size, body morphometrics and condition of wild animals. While method can generate large datasets quickly, lack efficient processing tools create bottlenecks that delay management actions. We developed machine learning algorithm automatically (body length widths) southern right whales (Eubalaena australis, SRWs) from aerial photographs ( n = 8,958) collected by unmanned vehicles in Australia. Our approach utilizes two Mask R‐CNN detection models to: (i) masks for each whale (ii) estimate points along whale's axis. annotated dataset 468 images containing 638 train our models. To evaluate accuracy approach, we compared model‐generated manual measurements. The influence picture quality (whale posture water clarity) was also assessed. estimates were slightly negatively biased (median error −1.3%), whereas volume had small 6.5%) positive bias. After correcting both biases, resulting mean absolute errors 0.85% (SD 0.75) 6.88% 6.57), respectively. magnitude decreased as increased. When using data quantify intra‐seasonal changes SRW females, obtained similar slope parameter (−0.001843, SE 0.000095) derived measurements (−0.001565, 0.000079). This indicates able accurately capture temporal trends at population level.

Язык: Английский

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The Southern Ocean pelagic ecosystems around the Antarctic Peninsula

Elsevier eBooks, Год журнала: 2025, Номер unknown, С. 303 - 322

Опубликована: Янв. 1, 2025

Язык: Английский

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Drones Applied to Cetacean Research: A Case Study of Fin Whales

IntechOpen eBooks, Год журнала: 2025, Номер unknown

Опубликована: Май 21, 2025

The fin whale is the only species regularly found in Mediterranean Sea, with a year around presence. However, aquatic environment and whale’s diving behavior have posed challenges to studying this marine mammal. increasing use of drones cetacean research has significantly enhanced our understanding species. Drones provide ability quickly discreetly fly over whales, minimizing disturbance, while capturing high-quality footage that enables observation their characteristic features used for identification, as well supporting morphometric analysis. Additionally, can assist collecting blow samples guiding vessels closer, more effective approaches conduct biopsies, collect fecal samples, or deploy tagging devices. This technological advancement greatly contributed deeper offering valuable insights into health population.

Язык: Английский

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