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Wheres Whaledo is a software toolkit that uses a combination of automated processes and user interfaces to greatly accelerate the process of reconstructing animal tracks from arrays of passive acoustic recording devices. Passive acoustic localization is a non-invasive yet powerful way to contribute to species conservation. By tracking animals through their acoustic signals, important information on diving patterns, movement behavior, habitat use, and feeding dynamics can be obtained. This method is useful for helping to understand habitat use, observe behavioral responses to noise, and develop potential mitigation strategies. Animal tracking using passive acoustic localization requires an acoustic array to detect signals of interest, associate detections on various receivers, and estimate the most likely source location by using the time difference of arrival (TDOA) of sounds on multiple receivers. Wheres Whaledo combines data from two small-aperture volumetric arrays and a variable number of individual receivers. In a case study conducted in the Tanner Basin off Southern California, we demonstrate the effectiveness of Wheres Whaledo in localizing groups of Ziphius cavirostris. We reconstruct the tracks of six individual animals vocalizing concurrently and identify Ziphius cavirostris tracks despite being obscured by a large pod of vocalizing dolphins.

Short-latency auditory-evoked potentials (AEPs) were recorded non-invasively in the bottlenose dolphin Tursiops truncatus. The stimuli were two sound clicks that were played either monaurally (both clicks to one and the same acoustic window) or dichotically (the leading stimulus (masker) to one acoustic window and the delayed stimulus (test) to the other window). The ratio of the levels of the two stimuli was 0, 10, or 20 dB (at 10 and 20 dB, the leading stimulus was of a higher level). The inter-stimulus intervals (ISIs) varied from 0.15 to 10 ms. The test response magnitude was assessed by correlation analysis as a percentage of the control (non-masked) response. At monaural stimulation, the test response was of a constant magnitude (5–6% of the control) at ISIs of 0.15–0.3 ms and recovered at longer ISIs. At dichotic stimulation, the deepest suppression of the test response occurred at ISIs of 0.5–0.7 ms. The response was slightly suppressed at short ISIs (0.15–0.3 ms) and recovered at ISIs longer than 0.5–0.7 ms. The relation of parameters of the forward masking to echolocation in dolphins is discussed. [ABSTRACT FROM AUTHOR]

Objective: To apply the more accurate technique for mandibular superimposition and provide a valuable reference for the assessment of mandibular tooth movement and condylar remodeling before and after orthodontic treatment. Methods: This retrospective study involved 38 adult patients who underwent two cone beam computer tomography (CBCT) scans at different stages of treatment at Fujian Provincial People’s Hospital between September, 2020 and December, 2022. The software Dolphin was used for mandible segmentation, enabling voxel‐based mandibular superimposition with the mandibular ramus as the reference region. The Geomagic Wrap software was employed to process surface‐based mandibular superimposition with the mandibular ramus as a reference. Additionally, the voxel and surface‐based methods were compared for precision, with the mandibular ramus being the reference. Results: After voxel‐based mandibular superimposition using the mandibular ramus as a reference, with all measurement errors (< 0.20 mm). In contrast, the results of surface‐based mandibular superimposition with the same reference, and the measurement errors were all less than 0.10 mm. The Wilcoxon signed‐rank test revealed statistically significant differences between AS1 and BS1, AS2 and BS2, AS3 and BS3, and AS4 and BS4 (all r< 0.05). Moreover, the absolute mean distances of AS1-AS4 were all greater than those of BS1-BS4. Conclusion: All mandibular superimposition procedures, including the voxel‐ and surface‐based ones using the mandibular ramus as a reference, have acceptable surface errors (< 0.20 mm), indicating the good reliability of these techniques. Under the specified conditions, surface‐based mandibular superimposition appears to yield a higher degree of precision compared with the voxel‐based technique. [ABSTRACT FROM AUTHOR]

Background We investigated the impact of Drug–Drug Interactions (DDIs) on virologic control among HIV-positive pregnant women initiating antiretroviral therapy while identifying drivers for Traditional Medicine (TM) use and exploring the nature and extent of TM-related DDIs. Methods Employing a three-pronged approach, we examined DDIs arising from comedication, including TM, in ART. The DolPHIN-2 trial (NCT03249181) randomized 268 HIV-positive pregnant women in Uganda and South Africa to dolutegravir (DTG)-based (135) or efavirenz-based (133) regimens while systematically recording comedications and screening for DDIs. We used Cox regression models to compare time-to-virologic control between participants with and without DDIs. We conducted in-depth interviews and focus group discussions among 37 and 67 women with and without HIV, respectively, to explore reasons for TM use during pregnancy. Additionally, in-vitro and in-vivo studies evaluated the composition and impact of clay-based TM, mumbwa , on DTG plasma exposure. Results The baseline prevalence of DDIs was 67.2%, with TM use prevalent in 34% of participants, with mumbwa being the most frequent (76%, 69/91). There was no difference in virologic response between participants with and without DDIs. Fetal health and cultural norms were among the reasons cited for TM use. Analysis of mumbwa rods confirmed significant amounts of aluminium (8.4%–13.9%) and iron (4%–6%). In Balb-C mice, coadministration of mumbwa led to a reduction in DTG exposure observed in the AUC0-24 (−21%; P  = 0.0271) and C24 (−53%; P  = 0.0028). Conclusions The widespread use of clay-based TM may compromise HIV treatment, necessitating medication screening and counselling to manage DDIs in pregnant women. [ABSTRACT FROM AUTHOR]

Because climate change and the biodiversity crisis are driven by human actions, determining psychological mechanisms underpinning support for environmental action is an urgent priority. Here, we experimentally tested for mechanisms promoting conservation-related motivation and behavior toward a flagship species, wild Tamanend's bottlenose dolphins. Following evidence that empathy increases prosocial motivations and behavior, and that the ability to identify individual humans promotes empathy, we tested whether this relationship applied to the ability to identify individual dolphins. Participants identified dolphins from their dorsal fins at above chance levels, and better individuation correlated with higher empathy for dolphins and higher willingness to pledge environmental behaviors. Pairing a narrative with an image of an injured dolphin leads to higher donations relative to a narrative alone. Our novel finding that the ability to individually identify dolphins relates to empathy and conservation-related behavior suggests pathways for strengthening environmental attitudes and behavior. [ABSTRACT FROM AUTHOR]

Small vessels contribute substantially to coastal soundscapes, presenting myriad potential impacts on marine species and ecosystems, yet are challenging to monitor using standard tracking methods (e.g. AIS). Here, we present an automated camera system developed to quantify coastal vessel traffic in a core habitat for Hector's dolphins (Cephalorhynchus hectori) within Akaroa Harbour, Aotearoa New Zealand. Analysis of 55,569 images taken during the austral summer of 2019/20 showed that traffic was highest around midday, on weekends, and in January. A mean of 41.9 vessel trips per day transited the area of core habitat. Vessel speeds estimated from photographs were assigned to 5-knot bins with 84% accuracy. Findings suggest vessel traffic in Akaroa Harbour has approximately doubled between 2006–2008 and 2020. Additionally, tours focused specifically on dolphins composed a significantly larger proportion of vessel traffic in 2020 than observed during 2006–2008. We validate the use of an automated camera system as a robust, novel, repeatable, and cost-effective tool for quantifying fluctuations in coastal vessel traffic. Such tools can provide baseline data and help assess impacts, and their use can guide management action. [ABSTRACT FROM AUTHOR]

This paper deals with estimating the underlying parameter of a length-biased inverse Gaussian distribution, when the observations are prone to length-biased sampling. Length-biased sampling occurs when the observations of smaller lengths or dimensions are neglected from the sample. We focus on a particular type of sequential fixed-accuracy confidence interval for estimation purposes. This method proves to be both time and cost efficient as one is able to perform the estimation using an optimal number of observations according to some set criteria. We discuss the applicability of our proposed method with regards to estimating the cluster size of the "Eastern Tropical Pacific Dolphins", which are often vulnerable to length biasedness. [ABSTRACT FROM AUTHOR]

Amitav Ghosh's The Hungry Tide operates in the archipelago of the Sunderbans and explores characters who reside in different quadrants of the socio-political map, navigating the difficult nexus between the survival of humans and conservation of the non-human. The key to this navigation is an important, and often ignored, historical event in his fiction—the Marichjhapi massacre of 1979. The massacre was enabled by West Bengal government's primacy on ecology and disregard for the fundamental rights of the people. This massacre and its impact on subsequent generations of that locality have been brushed aside in Indian mainstream history. Events of Marichjhapi have been deemed problematic for both nationalist sentiment and environmental conservation—two things that were of growing popularity during that time. In his narrative of deltas and dolphins, Ghosh manages to carve out the space for such a difficult event regarding people through a literary device that is often personal—a diary. Ghosh's narrativization of the events in Marichjhapi through Nirmal's diary, along with his characterization of local representatives such as Fokir, gives new understandings of the sufferings faced by the marginalized communities and the narrative challenges of relaying their voices—while showing the interconnectivity of people and their environment at large. [ABSTRACT FROM AUTHOR]

Humans, dolphins, and elephants are the only known species that vocally label their conspecifics. It remains unclear whether nonhuman primates share this ability. We recorded spontaneous “phee-call” dialogues between pairs of marmoset monkeys. We discovered that marmosets use these calls to vocally label their conspecifics. Moreover, they respond more consistently and correctly to calls that are specifically directed at them. Analysis of calls from multiple monkeys revealed that family members use similar calls and acoustic features to label others and perform vocal learning. These findings shed light on the complexities of social vocalizations among nonhuman primates and suggest that marmoset vocalizations may provide a model for understanding aspects of human language, thereby offering new insights into the evolution of social communication. [ABSTRACT FROM AUTHOR]

Marine organisms continually adapt their physiology and behaviour to temporal variations in their environment, resulting in diurnal rhythmic behaviour, particularly when foraging. In delphinids, these rhythms can be studied by recording echolocation clicks, which can provide indicators of foraging activity. The foraging rhythms of delphinids and their relationship to temporal parameters are poorly documented and most studies so far have used moored passive acoustic systems. The present study provides, for the first time, information on the activity rhythms of delphinids investigated in relation with temporal variables at a basin scale from a moving platform, in the western and central Mediterranean Sea. We used passive acoustic recordings collected by hydrophones towed along transect lines during the ACCOBAMS Survey Initiative in the summer 2018. We extracted variables that may influence daily and monthly rhythms, including time of day, lunar cycle, lunar illumination and sea state and fitted generalised additive models. The nycthemeral and lunar cycles were the two main factors influencing dolphin activity rhythms. Echolocation activity was predominant at night, with a maximum of 0.026 acoustic events per minute at 21:00/22:00 compared to as few as 0.0007 events per minute at 11:00. These events were also more frequent during the third quarter of the moon; 0.033 acoustic events on day 22 of the lunar cycle as opposed to 0.0008 on day 8 of the lunar cycle, corresponding to the first quarter of the moon. Variations in the echolocation activity of delphinids in the Mediterranean Sea could reflect variation in their foraging effort and be related to prey density, composition, accessibility and catchability within dolphin foraging depth range. These results should also improve interpretation of passive acoustic monitoring data. [ABSTRACT FROM AUTHOR]

Simple Summary: Our research focuses on the franciscana dolphin, the most threatened dolphin in the southwestern Atlantic, mainly due to its frequent entanglement in artisanal gillnets. This has led to their classification as vulnerable. To better understand their sounds and communication, we recorded and analysed the sounds of both wild dolphins and those in a rehabilitation centre. We found that neonate dolphins emit sounds that differ from those of juveniles. Interestingly, the sounds made by juvenile dolphins are similar to those of wild dolphins. We also discovered patterns in the way dolphins produce clicks, sounds which are important for feeding and communication. Our findings highlight the need to protect calf dolphins and suggest that it might be possible to create tools to identify dolphins by their age, based on their sounds. This research is important for conservation efforts and could help in creating better protection strategies for these dolphins. The franciscana dolphin is a small, vulnerable species often caught in artisanal gillnets. This study aims to provide a comprehensive assessment of their acoustic capabilities by using advanced equipment to collect a large dataset of wideband, continuous recordings. We examined the detailed acoustic signals of franciscana dolphins, comparing the sounds from rehabilitated dolphins in captivity with those of wild dolphins near fishing nets. Significant differences in acoustic characteristics were found between neonates and older dolphins, with juvenile and wild dolphins showing similar features. For the first time, repetition patterns in click production were identified, highlighting the importance of understanding the context of these sounds in regards to feeding and communication. This study emphasizes the need for detecting neonates for species protection and suggests the potential for developing acoustic classifiers specific to different age groups. Our findings offer valuable insights for conservation efforts and the development of protection strategies for franciscana dolphins. [ABSTRACT FROM AUTHOR]

Assessing trends in population abundance and demographics is crucial for managing long‐lived and slow‐reproducing species. Obtaining demographic data, and age‐structure information, is challenging, notably for cetaceans. To address this, we combined Unoccupied Aerial System (UAS; drone) photogrammetry data with long‐term (>20 years) photo identification data to assess the age‐structure of the critically endangered sub‐population of common bottlenose dolphins (Tursiops truncatus) of the Gulf of Ambracia, Greece. We compared our findings with two extensively studied non‐endangered bottlenose dolphin populations (T. aduncus in Shark Bay, Australia, and T. truncatus in Sarasota Bay, USA). Using a log‐linear model, we estimated the total body lengths (TL) of 160 known‐aged dolphins between 2021 and 2023 from blowhole‐to‐dorsal‐fin distance (BHDF) measurements collected during surfacing. Subsequently, we tested four growth models to establish an age‐length growth curve. We assessed the sub‐population's age‐structure using three methods: (1) UAS‐derived TL estimates, (2) age‐length growth curve and (3) long‐term monitoring data (i.e. actual age‐structure). UAS‐measured TL (247.6 ± 32.2 cm) and UAS‐estimated TL (246.0 ± 34.7 cm) of the Greek sub‐population showed no differences. The Richards Growth model suggested an asymptotic length of 258.5 cm. In Greece, resulting age‐structure estimates across the three methods revealed no significant differences (P > 0.1). The Gulf of Ambracia and Shark Bay populations shared similar age‐structures, while Sarasota had higher proportions of 2–10 year‐olds and lower proportions of 10+ year‐olds. All populations had a comparable proportion of 0–2 year‐olds (~14%), indicating a similar reproductive rate. Our findings suggest stability in the Greek sub‐population; however, additional monitoring of reproductive parameters is essential before concluding its status. We demonstrated the effectiveness of UAS‐photogrammetry in rapidly quantifying population age‐structure, including scenarios with limited or no demographic data. This technique shows promise for enhancing precision, timeliness, cost‐effectiveness and efficiency in population monitoring and informing timely conservation management decisions. [ABSTRACT FROM AUTHOR]

Understanding interactions within and between species is crucial to ecological research. However, for cetaceans such interactions can be difficult to observe in the field. Photographs offer an opportunity to study intra‐ and inter‐specific interactions, by capturing 'snapshots' of their occurrence over space and time. At‐surface and underwater photographs of bottlenose dolphins (Tursiops aduncus) inhabiting Ponta do Ouro Partial Marine Reserve (PPMR), Mozambique, were used to examine evidence of interactions with other dolphins, predators and ectoparasites. Intra‐specific scarring levels significantly differed by sex and age class, with males displaying more scarring than females. Similarly, adults had more scarring than juveniles or calves. Shark bites significantly differed in their distribution across dolphin body areas, with the dorsal side being more frequently wounded than the ventral side. The presence of barnacles was exclusive to fluke, dorsal and pectoral fins, and showed strong seasonal trends. Overall, this study demonstrates the value of photographs for examining marine ecological interactions. It provides the first insights regarding dolphin social behaviour, predation risk and health for this population. These in turn will support future research into the population dynamics and conservation of the PPMR dolphins, which is urgently required in the face of locally increasing anthropogenic pressures. [ABSTRACT FROM AUTHOR]

A female narrow-ridged finless porpoise (Neophocaena asiaeorientalis) stranded on a beach on Jeju Island showed epithelial proliferative skin lesions on its body. Two false killer whales (Pseudorca crassidens), caught using nets near Gangneung and Samcheok, respectively, had multiple plaques on their penile epidermis. Histological examination of the epidermis revealed that all the lesions had common features, including accentuated rete pegs, ballooning changes, and eosinophilic intranuclear inclusion (INI) bodies. Based on the histopathological results, herpesvirus infection was suspected, and thus further analysis was conducted using herpesvirus-specific primers. Based on nested polymerase chain reaction (PCR) tests using the herpesvirus-detectable primers, the PCR products demonstrated two fragments: a 222-base-pair (bp) sequence of the DNA polymerase gene, SNUABM_CeHV01, showing 96.4% identity with a bottlenose dolphin herpesvirus from the Jeju narrow-ridged finless porpoise; and a 222 bp sequence of the DNA polymerase gene, SNUABM_CeHV02, showing 95.95% identity with the same bottlenose dolphin herpesvirus from the Gangneung and Samcheok false killer whales. The significance of this study lies in its ability to demonstrate the existence of novel cetacean herpesviruses in South Korean seawater, representing an important step forward in studying potentially harmful pathogens that affect endangered whale and dolphin populations. [ABSTRACT FROM AUTHOR]

Recently, an acoustic individual identification (AIID) approach based on recognition of dolphins by individually distinctive calls such as "signature whistles" has been applied to bottlenose dolphins Tursiops truncatus. Some other Odontoceti species can also have individually specific calls: e.g., in beluga whales Delphinapterus leucas, these are so-called "contact calls". In this pilot study, we have tested the possibility of using the presumed contact calls of belugas to obtain the data on occurrence, number, and individual composition of their local aggregations in the natural environment. We have concluded that the diversity of contact calls can serve as an acceptable indicator of the number of individuals in the research area; in addition, these calls are potentially applicable for individual acoustic identification in belugas. [ABSTRACT FROM AUTHOR]

The advancement of intelligent technology has propelled the development of smart unmanned vessels into a new phase. To address the urgent demands of current smart ship development, this paper develops a comprehensive ship digital twin system based on a virtual-real mapping algorithm, focusing on the fundamental elements of digital twin model construction. Using the smart unmanned experimental ship Dolphin 1 as a prototype, a digital twin virtual model is proposed. This system leverages real-time internal and external data from the entire vessel to track its navigational status, performance indicators, sailing trends, and surrounding flow field information, offering coordinated "human-machine" navigation assistance. Based on historical data collected from the vessel's long-term navigation, a real-time precise prediction of the vessel's navigational state and hydrodynamic performance is conducted using physics-informed neural network algorithm. This establishes a self-learning iterative virtual-physical mapping model that enables autonomous updates and evolution. As the real navigation data of the vessel continuously update, the virtual model can more accurately simulate the vessel's state in real time. The proposed digital twin model has been tested through sea trials under real sea conditions, demonstrating its high accuracy, robustness, and potential for enhancing navigational safety and efficiency. This system marks a significant step forward in the integration of digital twin technology with maritime navigation, providing a valuable tool for the future development of smart shipping. [ABSTRACT FROM AUTHOR]

In this study, we examined the usefulness of a simpler and more feasible method for determining the optimal timing of artificial insemination and the conditions for its success in six female common bottlenose dolphins. Pregnancy was successfully achieved in five dolphins by performing intrauterine insemination, using chilled semen stored for less than 3 days or frozen semen within 24 hr of exhibiting a peak serum estradiol (E2) level of 100 pg/mL or higher or on the day with a serum E2 level of approximately 100 pg/mL, measured with a simple measuring device. We concluded that the determining the optimal timing of intrauterine insemination by measuring serum E2 levels is a simpler and more useful method compared with the conventional approach. [ABSTRACT FROM AUTHOR]

The north-western coast of Africa is one of the most productive marine systems in the world, where a high diversity of cetacean species has been recorded. However, management of human activities that impact cetacean populations in the area is inadequate, in part due to poor knowledge on cetacean occurrence and the lack of systematic surveys. We reviewed existing knowledge on cetacean distribution between Morocco and Liberia and analyzed the spatial and temporal distribution of records, as well as species occurrence, further discussing the reported distribution ranges. The systematic literature review included 39 sources reporting on 36 species in the area, with a total of 2241 sightings and 2178 non-sighting records. Delphinus delphis (common dolphin) and Tursiops truncatus (bottlenose dolphin) are the two species with the highest number of sources reporting on them. This review reveals a spatially and temporally heterogeneous coverage of the area in the literature and published data on cetacean occurrence. In summary, although most of the compiled sources are recently published (2011-2020), the majority of records are from prior to 2000. In several range states, especially south of Senegal, little information is available. Therefore, the available information is unlikely to represent the current status of cetacean communities in the region. It is essential to fill knowledge gaps by increasing the collection of cetacean distribution data in the area, in order to support effective conservation measures and ensure sustainable utilization of the living marine resources in this rapidly developing region. [ABSTRACT FROM AUTHOR]

The capture and killing of free-living small cetaceans in the Faroe Islands is described. After being driven on-shore by motor vessels, the animals are killed without pre-stunning using officially-prescribed methods that involve severing the spinal cord and the associated blood vessels using a long-handled lance. The claim that this induces near instantaneous unconsciousness and death lacks supporting evidence: it is believed that the animals are simply paralyzed, not immediately rendered unconscious. The cervical and spinal arterial circulation of cetaceans differs from that of terrestrial mammals and it is likely the spinal lance does not completely destroy the supply of oxygenated blood to the brain. In conclusion, the entire process from driving the animals onto the shore, to restraint and to killing stranded cetaceans is very likely to be detrimental to their welfare. Detailed studies would be necessary to determine the veracity of the claimed efficacy of the process. A bespoke humane killer may improve welfare at the time of killing but its development is considered challenging. [ABSTRACT FROM AUTHOR]

In ensemble weather forecast, tropical cyclone (TC) tracks sometimes group together into trajectories parting away from each other. The goal of this study is to propose an objective method, based on a robust clustering approach, to detect such separation scenarios in the Japan Meteorological Agency Meso‐scale Ensemble Prediction System (MEPS) for three TCs: "Dolphin" (2020), "Nepartak" (2021), and "Meari" (2022). Taking advantage of the independence of the density‐based spatial clustering of applications with noise algorithm to the prior choice of the number of clusters, we first describe an objective way to calculate the aggregation distance, by searching the most frequent Euclidean distance between all the tracks. The clustering is then applied to the forecasted tracks, for each initialization time of MEPS (every 6 hr). Separation scenarios exist when the number of clusters is greater than one. Plain Language Summary: To predict the weather, meteorologists use numerical models to simulate the future condition of the atmosphere, that is, forecast, from an initial condition. By slightly modifying this initial condition, an ensemble of future conditions is available, which provides the likelihood of an event occurring. In the case of a tropical cyclone (TC), it is particularly important to estimate its future path and strength, to prepare for disasters. Sometimes, the forecasted paths visually separate into distinct directions. We propose a straightforward way to numerically detect this separation in the forecasts. The method is illustrated by the three cases studies: TCs "Dolphin" (2020), "Nepartak" (2021), and "Meari" (2022). Key Points: Detecting separation scenarios in forecasted tropical cyclone (TC) trajectories to help preparedness and mitigation measuresA clustering analysis is used as a simple but effective tool to detect separations in tracks, by grouping similar trajectoriesA separation scenario exists when the number of clusters for a given initialization time is greater than 1 [ABSTRACT FROM AUTHOR]

Introduction: Recent minimum population estimates are critical for effective marine mammal conservation, yet such estimates are often lacking at the stock or management level. Throughout the Main Hawaiian Islands, pantropical spotted dolphins (PSD; Stenella attenuata attenuata) are comprised of a pelagic and three island-associated stocks (O‘ahu, 4-Islands, and Hawai‘i Island). The insular stocks, in particular, face multiple anthropogenic and natural threats such as vessel impacts, fisheries interactions, marine debris, climate change, and disease. Prior to this study, no abundance estimates of the 4-Islands (i.e., the Maui Nui region) PSD stock existed that were suitable for management use and inclusion in stock assessment report calculations. Methods: We generated annual mark-recapture abundance estimates of naturally marked adults in a POPAN-framework using photo-identification data collected from small-boat surveys during 2014–2022 in the Maui Nui region. We extrapolated these estimates to the wider population using dorsal fin mark rates. Results and discussion: We collected data on 62 groups of PSD, throughout all months of the year, and with an average group size of 55.70 (SD = 17.31). We analyzed encounter histories of 174 distinct individuals. Annual recapture rate averaged 1.84 (SD = 1.32) with a maximum of 7. Individuals detected per year averaged 35.67 (SD = 21.16) with a maximum of 77 in 2017. Overall mark rate was 0.495 (SE = 0.010), resulting in total annual abundance estimates that averaged 154.87 (SE = 14.25) and ranged from 105 (SE = 13) in 2014 to 232 (SE = 31) in 2017. Although abundance estimates fluctuated, generally 250 animals or less used the study area each year and we found no overall evidence of a trend. Our benchmark results revealed a small population in need of monitoring given the numerous threats facing this stock, the uncertainty of their impacts, and the decreased resiliency and recovery potential of small populations to negative demographic and environmental stochastic events. Our findings, including documenting long-term site fidelity and year-round presence of PSD in Maui Nui, further signify this area as one of future research and conservation importance. [ABSTRACT FROM AUTHOR]

Dolphins are aquatic mammals, whose role in microbial ecology is not fully understood. It is critical to study the microbiota of dolphins kept in captivity, as close contact with humans could unpredictably affect both human and animal health. In this study, we investigated the gut microbiota of 15 captive common bottlenose dolphins, and the relationship of microbial diversity and composition with animals’ age, sex, birthplace (dolphinarium or wildlife), and direct contacts with dolphinarium visitors using high-throughput V3-V4 16S rRNA amplicon sequencing. Based on acquired sequencing data we calculated and compared alpha and beta diversity indexes, as well as conducted differential abundance analysis of identified bacterial taxa to find multivariable associations with dolphins’ age period, sex, birthplace, and type of contact with humans with linear models. There was no association between gut microbiota composition and diversity and dolphins’ age period, sex, and birthplace. However, there were significant differences (q-value ≤ 0.00018) in the relative abundance of Edwardsiella genus in dolphins that were in contact only with dolphinarium staff in comparison to dolphins that apart from dolphinarium staff also had contact with dolphinarium visitors. These results show that dolphins born in wildlife and dolphinariums do not have significant differences in gut microbiota composition and the microbiota of captive dolphins can be affected by their contact with humans. [ABSTRACT FROM AUTHOR]

Species distribution models (SDMs) can be used to predict distributions in novel times or space (termed transferability) and fill knowledge gaps for areas that are data poor. In conservation, this can be used to determine the extent of spatial protection required. To understand how well a model transfers spatially, it needs to be independently tested, using data from novel habitats. Here, we test the transferability of SDMs for Hector's dolphin (Cephalorhynchus hectori), a culturally important (taonga) and endangered, coastal delphinid, endemic to Aotearoa New Zealand. We collected summer distribution data from three populations from 2021 to 2023. Using Generalised Additive Models, we built presence/absence SDMs for each population and validated the predictive ability of the top models (with TSS and AUC). Then, we tested the transferability of each top model by predicting the distribution of the remaining two populations. SDMs for two populations showed useful performance within their respective areas (Banks Peninsula and Otago), but when used to predict the two areas outside the models' source data, performance declined markedly. SDMs from the third area (Timaru) performed poorly, both for prediction within the source area and when transferred spatially. When data for model building were combined from two areas, results were mixed. Model interpolation was better when presence/absence data from Otago, an area of low density, were combined with data from areas of higher density, but was otherwise poor. The overall poor transferability of SDMs suggests that habitat preferences of Hector's dolphins vary between areas. For these dolphins, population‐specific distribution data should be used for conservation planning. More generally, we demonstrate that a one model fits all approach is not always suitable. When SDMs are used to predict distribution in data‐poor areas an assessment of performance in the new habitat is required, and results should be interpreted with caution. [ABSTRACT FROM AUTHOR]

This follow-up study to the first assessment of Philippine marine mammal strandings (1998 to 2009) assesses the spatiotemporal variation of strandings and the top five most frequently stranded species from a 2005-2022 dataset. It identifies stranding hotspot areas, estimates species stranding rates/status, and examines species composition and other stranding information. The 18-year database contained 1,368 stranding events with an annual average of 76 events. The total annual stranding frequency increased over the initial study period but fluctuated in the last seven years. Of the 30 species of marine mammals known in the Philippines, 27 species (26 cetaceans and one sirenian) were recorded in stranding records, and the top five most frequently stranded were (1) spinner dolphins (Stenella longirostris), (2) dugongs (Dugong dugon), (3) Risso’s dolphins (Grampus griseus), (4) Fraser’s dolphins (Lagenodelphis hosei), and (5) melonheaded whales (Peponocephala electra). Strandings consisted mostly of single animals (95%), and 55% of animals stranded alive. For each of the top five species, the frequency of stranding events increased annually. There was a peak in stranding frequency during the pre-southwest inter-monsoon season (March-April-May) for spinner and Risso’s dolphins as well as melon-headed whales, with no seasonal trend for the Fraser’s dolphins and dugongs. We identified stranding hotspots within 15 × 15 km grids along the coastline of the major island groups: Luzon, Visayas, and Mindanao. Thirty-five percent (497 of 1,422 grids) of the Philippine coastline had stranding records, with the majority in Luzon (n = 238), followed by Mindanao (n = 130) and Visayas (n = 128). Thirty-five stranding hotspots were identified: 24 in Luzon, 10 in Mindanao, and one in Visayas. Species stranding status categories were generated from log transformed stranding rates per species into standardized classification by quartiles. The stranding status of the top five most frequently stranded species was “very frequent” for spinner dolphins, and “frequent” for Fraser’s and Risso’s dolphins, dugongs, and melon-headed whales. The spatiotemporal variation of stranded marine mammals reflects the dynamic nature of the Philippine archipelago driven by monsoons and inter-monsoons and is exacerbated by fishing pressure and illegal activities. This study showed the importance of robust long-term marine mammal stranding databases for monitoring strandings and generating relevant information essential for their conservation. [ABSTRACT FROM AUTHOR]

Strandings and opportunistic sightings represent an invaluable source of information on cetacean’s biodiversity in the Mexican Caribbean. Here, we document the stranding and rescue of two pantropical spotted dolphins Stenella attenuata (mother and male calf) near Tulum (Quintana Roo, Mexico), which died without a clear diagnosis of cause of death. This case confirms the occurrence of S. attenuata, increasing the number of local aquatic mammals to 20. As most of the other small cetaceans in this region, the conservation status of the species remains undefined, and more research is needed to better understand ecological and biological aspects of its population. [ABSTRACT FROM AUTHOR]

Vehicular Ad hoc Network (VANET) has recently gained significant attention as a means of enhancing the mobility, efficiency, and safety of applications in the intelligent transportation system. However, because of its high-speed mobility, wireless connectivity, and extensive node coverage, security is a more difficult procedure. The Sybil security threat on VANET is a growing problem today. The Road Side Unit (RSU) failed to synchronise its clock with the legal vehicle, then unplanned vehicles are predicted, thereby incorrect messages are transferred to them. In this paper, Competitive Dolphin Echolocation Optimisation (CDEO)-based Deep Residual Network is proposed for Sybil attack and RSU misbehaviour detection. Here, the effective routing process is performed using Fractional Glow-Worm Swarm Optimisation (FGWSO)-based traffic-aware routing protocol. In the base station, the Sybil attack detection is done. The Sybil attack detection process is done using a Deep residual network, which is trained by the proposed CDEO algorithm. The CDEO algorithm is devised by incorporating Dolphin Echolocation Optimisation (DEO) technique and Competitive Swarm Optimiser (CSO). Additionally, using the Deep residual network, the RSU misbehaviour detection is done. The performance of the developed method is compared with certain performance metrics, like precision, F1-measure, and recall of 0.9197, 0.9121, and 0.9046. [ABSTRACT FROM AUTHOR]

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The geometric shape of the submarine sail has a significant effect on the flow uniformity amount in the submarine impeller plane. In the present study, using a Hotwire and a five-hole probe, the downstream flow field for the three sail in the SUBOFF submarine model was investigated. Two of the sails have the same NACA0018 cross-section and height, one of which has a fillet on the leading-edge. The third sail has the NACA0018 cross-section which is shaped like a dolphin's dorsal fin. In this study, the rotational field of the vortex downstream of the sail has been studied. The presence of fillets at the leading-edge of the sail significantly reduces the amount and intensity of the vortex. The sail with a dolphin's dorsal fin geometry also has a significant effect on improving the flow quality. In addition, as the distance from the sail increases downstream, the wake becomes weaker. [ABSTRACT FROM AUTHOR]

Stranding events of marine mammals provide valuable opportunities to study their biology, health, and causes for mortality, such as interactions with predators. Here we document the stranding of a deceased adult spinner dolphin (Stenella longirostris) with a shark bite (possibly an injury) on Utila Island, Honduras. The findings may shed light on predator-prey dynamics and scavenging in the region. [ABSTRACT FROM AUTHOR]

This article discusses a study on estimating the population size of Eastern Caribbean sperm whales for conservation purposes. The researchers conducted surveys in the Lesser Antilles region and used photo identification and acoustic data to estimate the population size. They found that the population is structured at a small spatial scale and that previous data from Dominica is biased and does not represent the entire population. The study provides more accurate population estimates for sperm whales in the region and emphasizes the need to consider different vocal clans separately in conservation efforts. The study also highlights the limitations of the methods used and the importance of cultural diversity in conservation. [Extracted from the article]

This article presents a study on the measurement of telomere length (TL) in Pacific white-sided dolphins. Telomeres are repetitive sequences at the ends of chromosomes that can vary in length among individuals and change due to environmental factors. The researchers used a method involving scanning membranes and analyzing the images to measure TL in captive dolphins using blood samples, which is a first in this field. The study found that TL varied among individuals and did not significantly correlate with age or body weight. TL remained relatively stable within an individual over a 1.5-year period. The researchers suggest that further research is needed to understand the factors influencing TL dynamics in dolphins and how TL can be used to assess stress levels in marine mammals. [Extracted from the article]

The franciscana, Pontoporia blainvillei, is an endemic dolphin off the east coast of South America and is considered the most endangered cetacean in the western South Atlantic. In the present study, we analyzed the muscle tissue of 24 franciscana dolphins found on the coast of Espírito Santo (ES) between 2010 and 2019 to investigate trophic ecology using carbon and nitrogen stable isotope analysis. In addition, 127 prey were analyzed to identify the preferred prey. The most important prey species in the diet of the franciscana dolphins were Trichiurus lepturus, Chirocentrodon bleekerianus, and Pellona harroweri. The franciscana dolphins were grouped into three subareas according to where they were collected throughout the distribution: 1 (North), 2 (Center), and 3 (South). In subarea 1, the preferred prey were Stellifer spp., Isopisthus parvipinnis, and P. harroweri, while in subareas 2 and 3, the prey were similar, changing the order of preference among them (Stellifer spp., T. lepturus, and C. bleekerianus). Finally, we identify two possible ecological groups of franciscana dolphins on the coast of ES, influenced by different carbon sources. Our results improve our understanding of the franciscana dolphin's trophic ecology and habitat use, providing new information and guidelines for species conservation in the region. [ABSTRACT FROM AUTHOR]

This article discusses a study on bubble trails produced by Eden's whales in the South China Sea. The study found that bubble production is not limited to certain types of whales, but is also observed in baleen whales. The researchers observed bubble trails being produced by solitary individuals as well as pairs of whales. The behavior was documented through field surveys using video cameras and unmanned aerial vehicles. The findings contribute to our understanding of the behavior and ecology of Eden's whales. Further research is needed to better understand the causes and implications of this behavior. [Extracted from the article]

Maternal grouping dynamics involve trade‐offs between: (1) infant protection from predation (predation hypothesis), (2) infant protection from male harassment (infant safety hypothesis), and (3) reducing scramble competition for prey resources (foraging‐type scramble competition hypothesis). Using unmanned aerial vehicles, we assessed grouping dynamics in common dolphin (Delphinus delphis) groups containing mother‐calf pairs to address these hypotheses. We analyzed social aspects and structural group elements using generalized additive mixed models and modeled group formation using multinomial generalized estimating equations. Calf proportion was higher in very compact groups and in groups of 10–20 individuals but decreased in larger groups. The frequency of socio‐sexual behaviors increased in larger groups and decreased in groups with higher calf proportion. Calf distance to its nearest neighbor decreased with increasing group size and cohesion. With a higher proportion of calves, scatter (versus parallel) formation was less frequent. A calf's nearest neighbor was most often (55.4%) a nonmother. Calves showed a preference for being in the front center of the group. These results offer strong support for the predation and infant safety hypotheses and partial support for the foraging‐type scramble competition hypothesis. This work provides insight into the adaptive function of maternal strategies in a small delphinid. [ABSTRACT FROM AUTHOR]

Background: To reduce heat loss underwater, marine mammals cover their bodies with insulation. Cetaceans in particular rely solely on blubber for insulation which has low conductivity. Blubber establishes a great thermal gradient between the warmer body core and cooler body surface, reducing heat transfer to the environment. A temperature gradient within the blubber determines the conductive heat transfer from the body trunk, where conduction and convection are the primary heat transfer mechanisms in cetaceans. Therefore, measuring the temperature at the innermost part of the blubber, i.e., the temperature at the muscle–blubber interface (Tmbi), can enhance our understanding of thermoregulatory mechanisms in cetaceans. In thermoregulation, activity-induced heat produced by increased muscle metabolism is another factor that plays an important role, however, the effects of activity on Tmbi have not been investigated in cetaceans. To assess this relationship in free-swimming cetaceans, we measured Tmbi and activity levels in a captive Risso's dolphin (Grampus griseus) using an implantable biologging device. Results: Tmbi and activity data were analyzed for 11 days. The average Tmbi was 35.1 ± 0.6 ºC and the temperature gradient between Tmbi and the water temperature was 13.0 ± 0.7 ºC. Tmbi was higher during the daytime and lower in the early morning. The variation in Tmbi was best explained by both the activity levels and time of day. Tmbi did not simply increase with activity levels; it appeared to remain relatively constant at most activity levels. However, Tmbi appeared to decrease when the animal was inactive and increase when it was intensely active. Conclusion: Our results provide important insights into how a dolphin regulates its body temperature underwater. Thermal insulation by blubber and heat production by activity were suggested to play important roles in thermoregulation. Whole-body heat dissipation might be used to regulate temperature increases when heat production is excessive due to intense activity. During inactive periods, decreasing temperature gradient may help reduce heat loss from the body. [ABSTRACT FROM AUTHOR]

Background: Pathogenic Leptospira species are globally important zoonotic pathogens capable of infecting a wide range of host species. In marine mammals, reports of Leptospira have predominantly been in pinnipeds, with isolated reports of infections in cetaceans. Case presentation: On 28 June 2021, a 150.5 cm long female, short-beaked common dolphin (Delphinus delphis delphis) stranded alive on the coast of southern California and subsequently died. Gross necropsy revealed multifocal cortical pallor within the reniculi of the kidney, and lymphoplasmacytic tubulointerstitial nephritis was observed histologically. Immunohistochemistry confirmed Leptospira infection, and PCR followed by lfb1 gene amplicon sequencing suggested that the infecting organism was L.kirschneri. Leptospira DNA capture and enrichment allowed for whole-genome sequencing to be conducted. Phylogenetic analyses confirmed the causative agent was a previously undescribed, divergent lineage of L.kirschneri. Conclusions: We report the first detection of pathogenic Leptospira in a short-beaked common dolphin, and the first detection in any cetacean in the northeastern Pacific Ocean. Renal lesions were consistent with leptospirosis in other host species, including marine mammals, and were the most significant lesions detected overall, suggesting leptospirosis as the likely cause of death. We identified the cause of the infection as L.kirschneri, a species detected only once before in a marine mammal – a northern elephant seal (Mirounga angustirostris) of the northeastern Pacific. These findings raise questions about the mechanism of transmission, given the obligate marine lifestyle of cetaceans (in contrast to pinnipeds, which spend time on land) and the commonly accepted view that Leptospira are quickly killed by salt water. They also raise important questions regarding the source of infection, and whether it arose from transmission among marine mammals or from terrestrial-to-marine spillover. Moving forward, surveillance and sampling must be expanded to better understand the extent to which Leptospira infections occur in the marine ecosystem and possible epidemiological linkages between and among marine and terrestrial host species. Generating Leptospira genomes from different host species will yield crucial information about possible transmission links, and our study highlights the power of new techniques such as DNA enrichment to illuminate the complex ecology of this important zoonotic pathogen. [ABSTRACT FROM AUTHOR]

Introduction: The amygdala is a noticeable bilateral structure in the medial temporal lobe and it is composed of at least 13 different nuclei and cortical areas, subdivided into the deep nuclei, the superficial nuclei, and the remaining nuclei which contain the central nucleus (CeA). CeA mediates the behavioral and physiological responses associated with fear and anxiety through pituitary-adrenal responses by modulating the liberation of the hypothalamic Corticotropin Releasing Factor/Hormone. Methods: Five dolphins of three different species, belonging to the family Delphinidae (three striped dolphins, one common dolphin, and one Atlantic spotted dolphin), were used for this study. For a precise overview of the CeA's structure, thionine staining and the immunoperoxidase method using calbindin D-28k were employed. Results: CeA extended mainly dorsal to the lateral nucleus and ventral to the striatum. It was medial to the internal capsule and lateral to the optic tract and the medial nucleus of the amygdala. Discussion: The dolphin amygdaloid complex resembles that of primates, including the subdivision, volume, and location of the CeA. [ABSTRACT FROM AUTHOR]

Age of cetaceans is an important data set for their conservation and management. Although the chronological age of a toothed whale has traditionally estimated from the number of annual tooth growth layer groups (GLGs), this method has potential difficulties such as errors due to the subjectivity of the age-readers and time-consuming sample processing, in addition to lethal tooth sampling in many cases. To overcome these difficulties through a non-lethal approach, considerable amount of efforts has been made in recent years to construct chronological age estimation models based on the correlation between chronological and biological age expressed as the frequency of DNA methylation at CpG (cytosine-phosphate-guanine) sites. The present study, by using next-generation sequencing on DNA extracted from the skin tissues of 30 individuals (15 males and 15 females), performed methylation analysis on multiple CpG sites in the three genes previously reported as age-linked in cetaceans (GRIA2, TET2, and CDKN2A) to construct an age estimation model for Risso's dolphins. Key aspects of this study are: (1) the chronological ages of Risso's dolphins of wild origins used in this study had been determined by the GLGs of teeth prior to this study, and (2) as Risso's dolphins are said to have a lifespan of 30 years, samples were collected from individuals aged 1-29 years, covering from young to old ages. Among the 11 CpG sites in GRIA2, 6 CpG sites in TET2, and 7 CpG sites in CDKN2A analyzed, the CpG sites in GRIA2 showed a statistically significant correlation with age, whereas those in TET2 and CDKN2A did not show such a strong correlation. Using multiple regression analysis on the CpG sites in the three genes, the best fitted model was expressed as follows: y=-0.7548 + 5.6164x(GRIA2_CpG3) +2.6187x(TET2_CpG6)-1.5907x(CDKN2A_CpG3) (R²=0.7062, residual mean=2.98, standard deviation=2.3). With the mean error of 2.98 years between the estimated and known chronological ages, the accuracy of this model was found to be comparable to or higher than that of previously reported age estimation models for cetaceans. This study demonstrated for the future that the age of wild Risso's dolphins can be estimated by using their skin samples collected with minimal invasiveness. [ABSTRACT FROM AUTHOR]

Simple Summary: This study reviews the development of the cetacean stranding response program in Taiwan from 1994 to 2018, and examines 1320 stranding events involving 1698 animals across at least 27 species. The stranding rates have increased significantly over the years, with a notable rise in annual events from 16 to over 90. Seasonal variation demonstrates higher stranding rates during the northeastern monsoon season. The study highlights the spatial distribution of strandings, with the highest frequency in northern Taiwan and mass strandings predominantly in the southwest. Additionally, live strandings accounted for 29.5% of events and 38.9% of animals. The rescue and rehabilitation of some individuals have been conducted, and 15 individuals have been released since 2000. The findings underscore the diversity and stranding patterns of cetaceans around Taiwanese waters, and provide valuable information for developing conservation strategies in the western Pacific. A national cetacean stranding response program in Taiwan has evolved significantly in the past three decades. Initially co-ordinated by National Taiwan University from 1994, the program transitioned to the Taiwan Cetacean Society in 1999, and local governments took on a more prominent role after 2009. A comprehensive stranding database (1994–2018) has been maintained, which documented 1320 stranding events involving 1698 animals from at least 27 species. The most commonly stranded species include finless porpoises, bottlenose dolphins, Kogia spp., and Risso's dolphins. The stranding rates varied annually and seasonally, with increases noted from an average of 16 events per year for the first 3 years to 44–58 events per year between 1997 and 2015, and a sharp rise to over 90 events per year for the period of the last three years. Seasonal variations were also significant, with higher stranding rates during the northeastern monsoon (NEM, October to next April) than that during southwestern monsoon (SWM, May to September). From the aspect of distribution, more frequent and even strandings occurred along the coast of northern Taiwan, while mass strandings were concentrated in the southwestern counties during NEM. Among all strandings, 390 events (29.5%) and 660 animals (38.9%) were live ones. Under great effort in rescuing and rehabilitating 52 cases, 15 cetacean individuals have been released since 2000. Additionally, there have been 56 mass strandings involving at least 11 species since 1994, predominated by pygmy killer whales, particularly during the NEM season along the southwest coast. This study not only contributes to our understanding of the stranding patterns and diversity of the cetaceans in Taiwan, but also provides valuable insights for future conservation strategies on cetaceans in the western Pacific. [ABSTRACT FROM AUTHOR]

Dolphins, as apex predators, can be considered relevant sentinels of the health of marine ecosystems. The creation of 3D cell models to assess in vitro cell-to-cell and cell-to-matrix interactions in environmental-mimicking conditions, is of considerable interest. However, to date the establishment of cetacean 3D culture systems has not yet been accomplished. Thus, in this study, different 3D systems of bottlenose dolphin (Tursiops truncatus) skin fibroblasts have been analyzed. Particularly, novel scaffolds based on hyaluronic acid and ionic-complementary self-assembling peptides such as RGD-EAbuK and EAbuK-IKVAV have been compared to Matrigel. Histological and fluorescent staining, electron microscopy (TEM) analyses and viability assays have been performed and RT-PCR has been used to detect extracellular matrix (ECM) components produced by cells. Results showed that Matrigel induced cells to form aggregates with lower viability and no ECM production compared to the novel scaffolds. Moreover, scaffolds allowed dispersed cells to produce a collagenous ECM containing collagen1a1, laminin B1 and elastin. The HA-EAbuK-IKVAV scaffold resulted in the most suitable 3D model in terms of cell quantity and viability. The development of this innovative approach is the first step towards the possibility to create 3D in vitro models for this protected species. [ABSTRACT FROM AUTHOR]

Accurate whistle contour extraction is crucial in many dolphin behavioural studies. Traditionally, whistle contour extraction involves a first step of finding whistle candidates by peak-level detection in the time-frequency domain, followed by a determination of when peaks are close enough to each other to be part of the same whistle contour. In complex scenarios, such as those with a large number of individuals vocalising simultaneously or those with a sudden increase in background noise, peak-level detection may not provide a number of accurate whistle candidates that is large enough to extract the whistle contour or to disambiguate individual whistles when they cross one another. In these adverse scenarios, a different approach, based on the pyknogram representation, can produce a more accurate detection of whistle candidates and evenly distributed candidates throughout the duration of the whistle. This work compares the peak-level extraction approach of the spectrogram with the point-density extraction approach of the pyknogram. We propose a technique that combines estimates of the central frequency and bandwidth to extract whistle candidates in adverse scenarios. The method has been successfully used for the vocalisation extraction of dolphins in the Bay of Biscay (Spain) using a database of more than 2000 dolphin whistles. [ABSTRACT FROM AUTHOR]

Dolphins are social animals that depend on sound to communicate, navigate, and find food. The aim of our research was to describe dolphin whistle characteristics and compare whistles between two isolated populations of bottlenose dolphins in New Zealand. We focused on three aspects of dolphin bioacoustics (1) classification of whistles; (2) comparison of the whistles of two discrete bottlenose dolphin populations; and (3) comparison of whistles of dolphin populations from around the world. At Great Barrier Island, the most common type of whistle was upsweep followed by sine, while at Doubtful Sound, convex and sine whistles were the most common whistle types. Random Forest models discriminated between whistles from the two populations with an estimated accuracy of 90%. The key differences were whistle-type contour, duration, and end frequency. Linear Mixed models show that whistle acoustic parameters were influenced by location but not by group size or the presence of immatures. Whistle parameters of both populations fell within the range of multiple populations from around the world. This studyprovides a benchmark for future research into drivers of geographic variation in dolphin vocal communication. [ABSTRACT FROM AUTHOR]

The article performs a comparative analysis of the underwater sounds of two sympatric dolphin species living in the Black Sea: bottlenose and common dolphins. During sound processing and analysis, the special program nanoCAD 22 was used. Both the similarity of the physical parameters of the sounds of the two species and a number of specific features of whistles characteristic of each were demonstrated. Common dolphin production of some types of whistles with significant similarities (sometimes almost identical) to the signature whistles of bottlenose dolphins was detected and analyzed. [ABSTRACT FROM AUTHOR]

In marine ecosystems, predators can affect community and ecosystem dynamics through a variety of processes such as foraging facilitation. Here, we report evidence of foraging facilitation between common bottlenose dolphins (Tursiops truncatus) and double-crested cormorants (Nannopterum auritum) in the Caribbean seagrass-dominated atoll of Turneffe, Belize using aerial drone observations conducted in 2015-2017. While dolphins exhibited occasional aggressive behaviours toward the cormorants, the latter frequently followed dolphin movements, suggesting opportunistic pursuit of dolphins for prey access during dolphin bottom foraging activity. Our observations underscore the intricate ecological relationships among marine predators and highlight the need to quantify the mutual benefits and costs of such interactions as coastal ecosystems are rapidly changing. [ABSTRACT FROM AUTHOR]

Biopsy has recently become a preferred protocol for sampling the skin and blubber of many cetacean species, although it is desirable to collect as minimally invasive as possible. Here, the effect of biopsy sampling on the captive common bottlenose dolphins was evaluated by analyzing the process of wound healing and changes in hematological and blood biochemical parameters after biopsy using a puncher developed to collect up to the inner layer of the dolphin blubber. Results showed that the wounds caused by biopsy were closed in as early as 1 day and completely covered with the epidermis within 5–11 days. Blood fibrinogen, which generally increases due to a wound‐induced inflammatory response or activation of the coagulation system, was significantly elevated after the biopsy indicating ongoing tissue repair, while other parameters did not exhibit significant differences. Furthermore, histological observation and RNA extraction of samples were performed to investigate the versatility of this method to cetacean research. Histological examination revealed three distinct layers of the blubber in the biopsy samples. Moreover, total RNA extracted from biopsy samples exhibited sufficient quality and quantity for gene expression analyses. Overall, the puncher utilized in our study represents a valuable and minimally invasive tool for investigating various aspects of small cetacean studies. Research highlights: •The developed biopsy puncher is a minimally invasive device that can collect up to inner layer of common bottlenose dolphin blubber, and can be used in a variety of investigations to better understand the metabolic activity and physiology of blubber. [ABSTRACT FROM AUTHOR]

A juvenile rough-toothed dolphin (Steno bredanensis) was live-stranded and rescued in Kanagawa Prefecture, Japan. From the results of diagnostic examinations, blood tests indicated that the dolphin was malnourished, dehydrated, and anemic. The dolphin died on sixth day of rescue despite treatment. At autopsy, 570 g of foreign material, including 34 pieces of cellophanes and plastic debris (PD), were found in the forestomach. Additional gross findings, including some endoparasitism and presence of accessory spleens were also identified. This is the first case in Japan which accidental ingestion of foreign bodies, including PD, was suspected to be the cause of death in a cetacean. [ABSTRACT FROM AUTHOR]