Publications by authors named "Bejder L"

Several legal acts mandate that management agencies regularly assess biological populations. For species with distinct markings, these assessments can be conducted noninvasively via capture-recapture and photographic identification (photo-ID), which involves processing considerable quantities of photographic data. To ease this burden, agencies increasingly rely on automated identification (ID) algorithms.

View Article and Find Full Text PDF

Given recent declines in North Pacific humpback whale (Megaptera novaeangliae) reproductive output and calf survival, there is additional urgency to better understand how mother-calf pairs allocate energy resources across their migratory cycle. Here, unoccupied aerial system (UAS; or drone) photogrammetry was used to quantify the body size and condition (BC) of humpback whales on their Hawai'i (HI) breeding and Southeast Alaska (SEAK) feeding grounds. Between 2018 and 2022, we collected 2410 measurements of 1659 individuals.

View Article and Find Full Text PDF

Improving our understanding of energy allocation in reproduction is key for accurately parameterizing bioenergetic models to assess population responses to environmental perturbations and anthropogenic disturbance. We quantified the energetic cost of gestation in humpback whales (Megaptera novaeangliae) using historical whaling records, non-invasive unoccupied aerial system (UAS) photogrammetry and post mortem tissue samples. First, we estimated relative birth size using body length measurements of 678 mother-fetus pairs from historical whaling records and 987 mother-calf pairs measured in situ using UAS-photogrammetry.

View Article and Find Full Text PDF

Several animal species use tools for foraging; however, very few manufacture and/or modify those tools. Humpback whales, which manufacture bubble-net tools while foraging, are among these rare species. Using animal-borne tag and unoccupied aerial system technologies, we examine bubble-nets manufactured by solitary humpback whales () in Southeast Alaska while feeding on krill.

View Article and Find Full Text PDF

Spinner dolphins (Stenella longirostris subsp.) occupy the nearshore waters of several Hawaiian Islands. Due to their constrained behavioral pattern and genetic isolation, they are vulnerable to anthropogenic threats.

View Article and Find Full Text PDF

For the 40 years after the end of commercial whaling in 1976, humpback whale populations in the North Pacific Ocean exhibited a prolonged period of recovery. Using mark-recapture methods on the largest individual photo-identification dataset ever assembled for a cetacean, we estimated annual ocean-basin-wide abundance for the species from 2002 through 2021. Trends in annual estimates describe strong post-whaling era population recovery from 16 875 (± 5955) in 2002 to a peak abundance estimate of 33 488 (± 4455) in 2012.

View Article and Find Full Text PDF
Article Synopsis
  • Researchers are exploring how baleen whales locate dense prey in the ocean, focusing on their olfactory systems and potential for stereo-olfaction.
  • The study found a significant negative correlation between the width of whale nares and their trophic levels, indicating that whales adapted for better smell are more likely to eat zooplankton.
  • The findings suggest that certain baleen whale species may be able to detect odorants like dimethyl sulfide (DMS), which raises concerns about their potential for ingesting plastic through DMS detection.
View Article and Find Full Text PDF
Article Synopsis
  • Understanding the health status of long-lived species is crucial for their management, but traditional monitoring methods are slow, often taking decades to reveal changes in populations.
  • A new approach using Unoccupied Aerial Systems (UAS) photogrammetry was tested to assess the age structure of bottlenose dolphins, offering a potential early warning system for population decline.
  • Results showed that UAS estimates can accurately determine the total body length of dolphins and classify age groups effectively, with a high percentage of individuals being correctly allocated to their age classes within two years.
View Article and Find Full Text PDF
Article Synopsis
  • * The dataset covers 13 regions and includes data on 27,956 unique humpback whales from 2001-2021, with an impressive identification accuracy of 97-99% using advanced machine learning.
  • * This resource aims to facilitate collaborative research on humpback whales and their habitats, especially as the ocean undergoes significant ecological changes.
View Article and Find Full Text PDF

Quantifying the energy expenditure of animals is critical to understanding the cost of anthropogenic disturbance relative to their overall energy requirements. We used novel drone focal follows (776 follows, 185 individuals) and aerial photogrammetry (5372 measurements, 791 individuals) to measure the respiration rate and body condition loss of southern right whales (Eubalaena australis) on a breeding ground in Australia. Respiration rates were converted to oxygen consumption rate and field metabolic rate (FMR) using published bioenergetic models.

View Article and Find Full Text PDF
Article Synopsis
  • Lunge feeding is a unique, energetically demanding feeding mechanism found in rorqual whales, requiring precise movements and timing during foraging.
  • The study utilized multi-sensor tags and UAS footage to analyze how body size affects lunge feeding characteristics, such as speed and deceleration, for various whale species.
  • Results indicated that despite the expected lower foraging efficiency at higher speeds, maximum foraging speeds remained consistently high across different body sizes, revealing a positive correlation between body size and foraging efficiency.
View Article and Find Full Text PDF

Background: The reef manta ray () is a globally threatened species and an iconic tourist attraction for visitors to Indonesia's Komodo National Park (NP). In 2013, manta ray fishing was banned in Komodo NP and its surroundings, preceding the nationwide manta ray protection in 2014. Over a decade ago, a previous acoustic telemetry study demonstrated that reef manta rays had high fidelity to sites within the park, while more recent photo-identification data indicated that some individuals move up to 450 km elsewhere.

View Article and Find Full Text PDF
Article Synopsis
  • - The research focuses on the energetic costs of gestation in southern right whales, detailing how fetal growth rates and birth size correlate with the mother's body size.
  • - By analyzing historical whaling data and using photogrammetry, the study quantifies the costs associated with fetal maintenance and growth throughout different trimesters of pregnancy.
  • - Findings reveal that while fetal growth is rapid, the majority of gestation costs occur in the last trimester, with the heat of gestation accounting for the highest energy expenditure.
View Article and Find Full Text PDF
Article Synopsis
  • Whales, despite being massive, are active predators that need to be agile to capture smaller prey, leading to the development of unique movement strategies that require significant energy and mechanical power.
  • Research on seven baleen whale species shows that as whale size increases, their maneuvering performance, such as acceleration and agility, decreases, meaning larger whales are generally less agile than smaller ones.
  • However, larger whales adapt their behaviors to cope with their size, employing maneuvers that enhance their capability, indicating that they have evolved specific physical traits to optimize their movement despite their bulk.
View Article and Find Full Text PDF

Understanding the impacts of foraging disruptions to odontocete body condition is fundamental to quantifying biological effects of human disturbance and environmental changes on cetacean populations. Here, reductions in body volume of free-ranging pygmy killer whales (Feresa attenuata) were calculated using repeated measurements of the same individuals obtained through Unoccupied Aerial System (UAS)-photogrammetry during a prolonged disruption in foraging activity arising from a 21-day stranding event. Stranded individuals were used to verify UAS-derived volume and length estimates through 3D-imaging, water displacement, and post-mortem measurements.

View Article and Find Full Text PDF

Background: Plantar fasciitis is a common cause of heel pain. Monitoring therapy effects is challenging with conventional B-mode ultrasound. Shear wave elastography (SWE) provides important diagnostic information beyond B-mode, with typically lower tissue stiffness in symptomatic plantar fascia.

View Article and Find Full Text PDF

Increasing human activity along the coast has amplified the extinction risk of inshore delphinids. Informed selection and prioritisation of areas for the conservation of inshore delphinids requires a comprehensive understanding of their distribution and habitat use. In this study, we applied an ensemble species distribution modelling approach, combining results of six modelling algorithms to identify areas of high probability of occurrence of the globally Vulnerable Australian humpback dolphin in northern Ningaloo Marine Park (NMP), north-western Australia.

View Article and Find Full Text PDF
Article Synopsis
  • Human activities are significantly affecting biodiversity and the welfare of wild mammals, especially since individual welfare has been less studied despite its ethical importance.
  • There is an increasing focus on creating methods to assess these anthropogenic threats, leading to the development of the Wildlife Assessment Tool for Wild Cetaceans (WATWC).
  • The WATWC uses a comprehensive Five Domains model to evaluate welfare impacts, was tested on Southern Resident killer whales, and showed promise in identifying gaps in data and informing policy on human interactions with marine mammals.
View Article and Find Full Text PDF
Article Synopsis
  • Researchers linked stereo-laser photogrammetry with demographic data to study length-at-age growth curves of bottlenose dolphins in south-western and Shark Bay, Australia.* -
  • They found a strong correlation between total length and a specific body measurement, allowing for the estimation of sizes of 203 known-age dolphins using laser techniques.* -
  • The study revealed significant differences in adult sizes between the two populations, likely due to adaptations to different water temperatures, emphasizing the value of non-invasive methods for understanding marine species for conservation efforts.*
View Article and Find Full Text PDF
Article Synopsis
  • Genetic diversity is crucial for the adaptability of populations and is best measured by adaptive markers like the major histocompatibility complex (MHC), rather than just neutral markers like microsatellites.* -
  • In a study comparing two bottlenose dolphin populations in Western Australia, the Shark Bay group showed higher MHC diversity and greater reproductive success compared to the declining Bunbury population.* -
  • The findings suggest that MHC variation is a better indicator of population health and adaptability, highlighting its potential as a valuable genetic marker for conservation efforts.*
View Article and Find Full Text PDF
Article Synopsis
  • Southern right whale mothers invest a lot of energy into raising their calves while being at risk of predation from killer whales.
  • Researchers equipped nine lactating whales with multi-sensor DTAGs to study their vocalizations and the surrounding acoustic environment in Western Australia.
  • The findings showed that these whales vocalize infrequently and at low volumes, suggesting they use acoustic crypsis to protect their calves from predators, thereby safeguarding their significant energy investment.
View Article and Find Full Text PDF

Food-provisioning of wildlife can facilitate reliable up-close encounters desirable by tourists and, consequently, tour operators. Food-provisioning can alter the natural behavior of an animal, encouraging adverse behavior (e.g.

View Article and Find Full Text PDF

Rationale And Objectives: The current imaging standard for diagnosing plantar fasciitis is B-Mode ultrasound (B-US). The aim of this study was to determine the diagnostic potential of Shear Wave Elastography (SWE) and the correlation of clinical scores to elastographic parameters.

Materials And Methods: Diagnostic case-control study with n = 82 plantar fascia (PF).

View Article and Find Full Text PDF

Understanding the behaviour of humpback whale mother-calf pairs and the acoustic environment on their breeding grounds is fundamental to assessing the biological and ecological requirements needed to ensure a successful migration and survival of calves. Therefore, on a breeding/resting ground, Exmouth Gulf, Western Australia, we used animal-borne DTAGs to quantify the fine-scale behaviour and energetic expenditure of humpback whale mothers and calves, while sound recorders measured the acoustic environment. We show that: (i) lactating humpback whales keep their energy expenditure low by devoting a significant amount of time to rest, and their use of energy, inferred from respiration rates, is ~half than that of adults on their foraging grounds; (ii) lactating females mainly rest while stationary at shallow depths within reach of the hull of commercial ships, thus increasing the potential for ship strike collisions; (iii) the soundscape is dominated by biological sources; and (iv) even moderate increases of noise from vessels will decrease the communication range of humpback whales.

View Article and Find Full Text PDF