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Background: To tag large marine vertebrates, without the need to catch them, avoiding using barbs for tag retention, and precisely controlling tag location, the remote Tag Attachment Device on a pole (TADpole) was developed. This allows single-pin tags (Finmount, Wildlife Computers) to be attached to the dorsal fins of free-swimming large marine vertebrates. Results: TADpole comprises a pole-mounted holster that carries a tag. It uses compressed air, and a micro-controller, to rapidly insert a stainless-steel pin through a corrodible metal retaining ring in the first tag attachment wing, the animal's dorsal fin, and then a press fit Delrin retaining ring in the tag wing on the other side of the fin. Tagging only occurs when the trailing edge of the dorsal fin touches a trigger bar in the holster, ensuring optimal pin placement. It was developed using fins from cadavers, then trialed on briefly restrained coastal dolphins that could be followed in successive days and weeks, and then on free-swimming animals in the field. The latter showed very short touch/response intervals and highlighted the need for several iterative revisions of the pneumatic system. This resulted in reducing the total time from triggering to tag application to ~ 20 ms. Subsequent efforts expanded the TADpole's applicability to sharks. One free-swimming Atlantic spotted dolphin, two white sharks, and one whale shark were then tagged using the TADpole. Conclusions: Being able to tag free-swimming dolphins and sharks remotely and precisely with satellite-linked telemetry devices may contribute to solving conservation challenges. Sharks were easier to tag than dolphins. Dolphin touch-to-response times were 28 ms or less. Delphinid skin has unique polymodal axon bundles that project into the epidermis, perhaps a factor in their uniquely fast response, which is 10 × faster than humans. Their primary reaction to tagging is to abduct the flippers and roll the fin out of the TADpole holster. This device has the potential to deliver high-quality tag data from large vertebrates with dorsal fins without the stress and logistics associated with catch-and-release, and without the trauma of tags that use barbs for retention. It also collects a dorsal fin biopsy core. [ABSTRACT FROM AUTHOR]

Stranded marine mammals provide valuable insight into population health of free‐ranging conspecifics; however, the likelihood of carcass detection by the public or trained observers is not well known. To better understand carcass detection rates (CDR), we placed twelve decoy dolphin carcasses around Dauphin Island, Alabama, for 2 weeks, one during peak tourist season and one during the off season. Decoys were placed in regions representing different habitat types (marsh or beach) and levels of human use (low or high). Calls from the public were recorded, and trained observers actively searched for decoys via drone and visual observation either by vessel or UTV and walking. There were 2.5 times more public reports during the peak (n = 38) compared to off season (n = 15), with most reports being from the high‐traffic beach site during peak season (n = 27). Trained observers found more decoys (CDR = 0.88) than the public (CDR = 0.58), however, the public found two decoys that observers did not. Drone searches were slightly more successful (CDR = 0.83) than other methods (CDR = 0.79). Our results indicate that a combination of surveillance methods will enhance carcass detection, and our novel methods can be used across habitat types to improve stranding surveillance, better estimate stranding rates, and inform mortality estimates of many species. [ABSTRACT FROM AUTHOR]

Background and Aim: Cetaceans and sirenians are endangered marine mammals that are threatened by stranding and mortality. In Thailand’s Andaman Sea, limited data exist on the causes and patterns of these events. This retrospective study investigated the characterization and underlying causes of cetacean and sirenian mortality events in the Andaman Sea from 2018 to 2023 using information from the Department of Marine and Coastal Resources, Thailand. Materials and Methods: Data on 363 stranded marine mammals, including both live and dead strandings, species types, carcass condition, and necropsy findings and diagnoses, were gathered and analyzed to classify and determine the main factors contributing to mortality, encompassing both direct human-related and non-direct human-related causes. Results: From 2018 to 2023, 231 cetaceans and 132 sirenians were documented, representing six families and 19 species. Of these animals, 18.18% (66/363) were stranded alive and 81.81% (297/363) were found dead. The most common species were dugong (Dugong dugon) and Indo-Pacific humpback dolphin (Sousa chinensis). Detailed postmortem analyses of 107 specimens showed that 17.76% (19/107) of deaths were anthropogenic, affecting 8 sirenians and 11 cetaceans. The majority of deaths were non-anthropogenic, involving 34 sirenians and 54 cetaceans. In addition, 223 stranded animals could not be fully assessed due to carcass condition. Conclusion: A high cetacean and sirenian mortality rate in the Andaman Sea can be attributed to non-anthropogenic factors. The dugong and Indo-Pacific humpback dolphin were the most frequently encountered species. This report enhances our understanding of marine mammal mortality in Thailand and underscores the need for improved health management and diagnostic responses.

Background/purpose: The use of computed tomography (CT) for craniofacial measurements is common in medical imaging, but concerns about accuracy and reliability persist, especially with different CT technologies. This study assessed the accuracy of twenty-six common measurements on consecutive CT images from the same patients, using multidetector CT (MDCT) and cone-beam CT (CBCT) with two software programs (Amira and Dolphin). Materials and methods: Ten adult subjects with consecutive CBCT scans within one year were randomly selected. Another ten subjects with consecutive MDCT scans were paired with the CBCT group based on age, gender, race, occlusion, and craniofacial pattern. All digital imaging and communications in medicine (DICOM) files were randomly coded and analyzed using the two software programs. Intra-examiner reliability was assessed using the intraclass correlation coefficient. Successive measurement errors from consecutive scans for both imaging modalities and software programs were compared. Results: For most skeletal linear and angular measurements, Dolphin showed greater successive measurement errors compared to Amira. Eight of the 26 common measurements had errors greater than one unit (millimeter or degree). Despite almost perfect intra-examiner reliability for upper airway analysis, average successive measurement errors were notably high, particularly for intraoral and oropharyngeal airway volumes. The successive Dolphin measurement error for oropharyngeal airway volume on CBCT images was over three times that on MDCT images. Conclusion: Given the substantial successive measurement errors observed during consecutive CT scanning for the upper airway, this study does not support the quantitative use of CT for analyzing changes in airway dimensions for research purposes.

As fully aquatic mammals, hearing is arguably the most important sensory component of cetaceans. Increasingly, researchers have been harnessing computed tomography (CT) to investigate the details of the inner ear as they can provide clues to the hearing abilities of whales. We use microCT scans of a broad sampling of the ear bones (periotics) of primarily toothed whales (Odontoceti) to investigate the inner ear bony labyrinth shape and reconstruct hearing sensitivities among these cetaceans, including several taxa about which little is currently known. We find support for sensitivity to the lower frequency spectrum in the archaeocete Zygorhiza kochii and an early toothed mysticete cf. Aetiocetus. Oligocene odontocetes (including one from our novel dataset), stem delphinidans, and two additional species of the long‐snouted eurhinodelphinids are found to have been able to hear within the narrow‐band high‐frequency spectrum (NBHF), which is thought to be a specialized form of hearing that evolved convergently multiple different times in extant groups to avoid predation by macroraptorial predators. Our results thus indicate that NBHF evolved as early as the Oligocene and certainly in stem delphinidans by the early Miocene, and thus may be an ancestral characteristic rather than a more recent innovation in select groups. [ABSTRACT FROM AUTHOR]

Indo-Pacific bottlenose dolphin (Tursiops aduncus) is a marine mammal that lives in relatively small populations. The geographic ranges of this species are susceptible to the effects of human activities, thereby necessitating conservation efforts to prevent extinction. Therefore, this study aimed to evaluate the daily quality of dolphin sperm after several days of refrigeration. The sperm of two male dolphins were stored at 4oC for 4 days, and the quality was observed daily to determine the motility, viability, membrane integrity, and sperm abnormalities. Sperm samples were divided into four groups, consisting of two centrifuged followed by the removal of seminal plasma, and two groups without centrifugation, containing 100x106 and 200x106 sperm/ml each. After liquid storage, the motility of sperm was 63-75% with no significant reduction in the first 3 days. Sperm viability following storage was 65-75% and the percentage with abnormal morphology ranged from 2-6%. Furthermore, there was no significant increase in abnormal morphology of sperm on any day of storage for 3 days. Sperm membrane integrity was 36-49%, with no significant reduction in the membrane integrity in the first 2 days. There was no significant difference in sperm quality, although centrifugation and removal of seminal plasm had a slight effect. The results of this study showed that Indo-Pacific bottlenose dolphin sperm could be stored for a short period as liquid storage while maintaining a quality that allows for future use. [ABSTRACT FROM AUTHOR]

The franciscana (Pontoporia blainvillei) is a small cetacean endemic to the southwestern Atlantic Ocean in a vulnerable conservation status. Their habitat is restricted to shallow waters and estuaries. In 2020, fresh female carcass of franciscana (juvenile/subadult) was found dead alone (individual stranding) on a public access beach in the Rio Negro Estuary in "Balneario El Cóndor", Argentinian Patagonia. Grossly, a widespread granulomatous lesion compatible with tuberculosis were observed. A sample of mesenteric lymph nodes with granulomatous lesions (~ 50 g) was collected for bacteriological culture and molecular identification. Bacterial growth was observed in Stonebrink media and Ziehl Neelsen staining revealed acid-fast bacilli. Identification of a Mycobacterium bovis strain with the SB0288 spoligotype was obtained. The spoligotype detected here has already been reported in cattle and humans. Presumably, fluids and feces of infected livestock and wild animals, or their carcasses, may contaminate the water. Thus, this report demonstrates the potential risk of zoonotic tuberculosis transmission through wastewater. Contaminated wastewater is eventually a threat to animal species living in the area, and potentially becomes a zoonotic risk. [ABSTRACT FROM AUTHOR]

Dolphin swimming has been a captivating subject, yet the dorsal fin's hydrodynamics remain underexplored. In this study, we conducted three-dimensional simulations of flow around a wall-mounted dolphin dorsal fin derived from a real dolphin scan. The NEK5000 (spectral element method) was employed with a second-order hex20 mesh to ensure high simulation accuracy and efficiency. A total of 13 cases were simulated, covering angles of attack (AoAs) ranging from 0 ° to 60 ° and Reynolds numbers (Re) between 691 and 2000. Our results show that both drag and lift increase significantly with the AoA. Almost no vortex was observed at AoA = 0 ° , whereas complex vortex structures emerged for AoA ≥ 30 ° , including half-horseshoe, hairpin, arch, and wake vortices. This study offers insights that can inform the design of next-generation underwater robots, heat exchangers, and submarine sails. [ABSTRACT FROM AUTHOR]

Different Late Neolithic and Early Bronze Age sites located in the Ras al-Hadd cape and Ras al-Jinz Bay area (Ash-Sharqiyyah South Governorate, Sultanate of Oman) have provided thousands of zooarchaeological dolphin remains suggesting a strong reliance on the exploitation of these animals. Dolphins are hard to identify to the species level due to a highly comparable interspecies osteological morphology as well as a general lack of extensive osteological reference collections. As a result, such remains are frequently identified as "dolphin", without any further species identification being undertaken. In this study, we assess whether an osteometric method for distinguishing the nine dolphin species that are present in Omani waters can be used to identify the zooarchaeological specimens. Zooarchaeology by Mass-Spectrometry (ZooMS) was also undertaken on a subset of the specimens but proved ineffective due to the poor preservation of the material in an arid climate. This evidence strengthens the need for effective species identification methods based on traditional zooarchaeological methods. This research is based on our ongoing analysis of the thousands of dolphin remains from the Omani zooarchaeological assemblages. [ABSTRACT FROM AUTHOR]

Simple Summary: Photobacterium damselae subsp. damselae (Pdd) is a marine bacterium that can infect a variety of marine animals and humans. Although this bacterium has been isolated from several stranded dolphins and whales, its pathogenic role in cetaceans is still unclear and very limited information exists on its occurrence in these animals. In this study, we report data relating to the presence of Pdd in marine mammals stranded within the Liguria Pelagos Sanctuary from 2017 to 2022. Our findings show a 41.5% (22/53) Pdd prevalence in stranded cetaceans, where 22.7% (5/22) of these were positive in at least one of the Pdd virulence factors which, in previous studies, have been related to Pdd pathogenicity. Our results also revealed that in all cases where cetaceans tested positive for Pdd, other well-known pathogens for these species were also present. This finding supports the hypothesis that Pdd is an opportunistic agent that might contribute to the worsening of health conditions in subjects already compromised by other pathogens, contributing to their death. However, further studies are necessary to investigate and deepen this hypothesis. Photobacterium damselae subsp. damselae (Pdd) is an increasingly common bacterium in post-mortem diagnostics of beached marine mammals, but little is known about its precise etiological responsibility. To estimate the prevalence of Pdd in stranded cetaceans from 2017 to 2022 on the Ligurian coast (Pelagos Sanctuary), we tested tissues from 53 stranded individuals belonging to four cetacean species. DNA extracts from cetacean tissue were screened using a polymerase chain reaction (PCR) assay targeting the Pdd ureC gene. Positive samples were screened by PCR for dly, hlyApl and hlyAch hemolysin genes, which were confirmed by sequencing. Twenty-two out of 53 (41.5%) cetaceans analyzed by PCR were confirmed for Pdd DNA in at least one tissue among those analyzed. Five of these cetaceans were positive for at least one of the hemolysin genes tested. In all Pdd-positive cetaceans, other pathogens that were considered responsible for the causa mortis of the animals were also found. The results provide new information on the spread of Pdd in cetaceans and support the thesis that Pdd might be an opportunistic agent that could contribute to worsening health conditions in subjects already compromised by other pathogens. However, further studies are needed to investigate and deepen this hypothesis. [ABSTRACT FROM AUTHOR]

The use of computed tomography (CT) for craniofacial measurements is common in medical imaging, but concerns about accuracy and reliability persist, especially with different CT technologies. This study assessed the accuracy of twenty-six common measurements on consecutive CT images from the same patients, using multidetector CT (MDCT) and cone-beam CT (CBCT) with two software programs (Amira and Dolphin). Ten adult subjects with consecutive CBCT scans within one year were randomly selected. Another ten subjects with consecutive MDCT scans were paired with the CBCT group based on age, gender, race, occlusion, and craniofacial pattern. All digital imaging and communications in medicine (DICOM) files were randomly coded and analyzed using the two software programs. Intra-examiner reliability was assessed using the intraclass correlation coefficient. Successive measurement errors from consecutive scans for both imaging modalities and software programs were compared. For most skeletal linear and angular measurements, Dolphin showed greater successive measurement errors compared to Amira. Eight of the 26 common measurements had errors greater than one unit (millimeter or degree). Despite almost perfect intra-examiner reliability for upper airway analysis, average successive measurement errors were notably high, particularly for intraoral and oropharyngeal airway volumes. The successive Dolphin measurement error for oropharyngeal airway volume on CBCT images was over three times that on MDCT images. Given the substantial successive measurement errors observed during consecutive CT scanning for the upper airway, this study does not support the quantitative use of CT for analyzing changes in airway dimensions for research purposes. [ABSTRACT FROM AUTHOR]

Understanding reproductive output and success is integral to the conservation and management of threatened species and populations. Little is known about the reproductive parameters of Australian humpback dolphins (Sousa sahulensis), a species subject to cumulative pressures from anthropogenic threats due to their coastal distribution and strong site fidelity. This study assesses several reproductive parameters, including crude birth, recruitment, fecundity, and calf survival rates, in addition to interbirth intervals of Australian humpback dolphins inhabiting the near‐urban embayment of Moreton Bay, Queensland. Between 2014 and 2020, 106 adult females were photographically identified during 222 boat surveys. Of these, 75.5% (n = 80) were observed with calves. Birth seasonality was apparent and coincided with austral autumn and winter months. Interbirth intervals ranged between 1 and >6 years, with an average of 3.1 (SD = 1.1) years if offspring survived. Findings indicate declining fecundity rates (p <.05, M = 0.12, SD = 0.02), relatively low recruitment rates (M = 0.04, SD = 0.01) and calf survival rates to 1 year of age (M = 0.63, SD = 0.15). This study provides a useful baseline that can inform viability assessments and conservation measures, for both this population and others throughout the species range. [ABSTRACT FROM AUTHOR]

Natural climatic changes and human activities affect environmental balance influencing various global ecosystems including the aquatic one. Here the Gangetic ecosystem of India with Dolphin is focused. The Ganges is India's longest river and its lifeline contributing immensely to the country's overall GDP. Again, it is home to many animals including the Dolphin, recognized to be a reliable health indicator with its hydrodynamic body system which works efficiently by the smart natural technique of echolocation and desquamation. However, industrial effluents, agricultural runoffs, discharge of untreated wastewater along with sedimentation produce gross negative effects on the Gangetic environment. These directly pollute the river, disrupt its regular flow, and obstruct the normal activities of the Dolphin, thus destroying its habitat which ultimately reduces the population and affects the river's bio-diversity balance. Country-wide lockdown during the COVID-19 Pandemic temporarily stops all human interventions. The net outcome is the rejuvenation of the water quality confirmed by the reappearance of the Dolphins after several years along its various stretches. So how the identified steps should be practiced to maintain the Gangetic ecosystem, while maintaining the country's economic growth, has been considered as the greatest challenge here.

Diving marine mammals are a diverse group of semi‐ to completely aquatic species. Some species are targets of conservation and rehabilitation efforts; other populations are permanently housed under human care and may contribute to clinical and biomedical investigations. Veterinary medical care for species under human care, at times, may necessitate the use of general anesthesia for diagnostic and surgical indications. However, the unique physiologic and anatomic adaptations of one representative diving marine mammal, the bottlenose dolphin, present several challenges in providing ventilatory and cardiovascular support to maintain adequate organ perfusion under general anesthesia. The goal of this review is to highlight the unique cardiopulmonary adaptations of the completely aquatic bottlenose dolphin (Tursiops truncatus), and to identify knowledge gaps in our understanding of how those adaptations influence their physiology and pose potential challenges for sedation and anesthesia of these mammals. [ABSTRACT FROM AUTHOR]

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]

The striped dolphin (Stenella coeruleoalba) is a medium‐sized pelagic dolphin with a single external nasal opening (blowhole) located in the rostral and dorsal regions of the skull. The nasal cavity is divided into three sections: the olfactory, respiratory, and vestibular areas. The surface epithelium lining the regio vestibularis is the first tissue in the nose to be directly affected by environmental antigens. Cetaceans have a significant amount of mucosa‐associated lymphoid tissue (MALT) located throughout their bodies. The lymphoid tissue found in the nasal mucosa is known as nose‐ or nasopharynx‐associated lymphoid tissue (NALT). NALT has not yet been studied in dolphins, but it has been identified and documented in humans and laboratory rodents. This study utilized toll‐like receptor 2 (TLR2), CD4, Langerin/CD207, and inducible nitric oxide synthase to characterize, for the first time, immune cells in the mucosal regio vestibularis of the S. coeruleoalba nasal cavity using confocal microscopy immunofluorescence techniques. The findings revealed scattered immune cells immunoreactive to the tested antibodies, present in both the epithelial tissue lining the nasal cavity vestibulum and the underlying connective tissue. This study enhances our comprehension of the immune system of cetaceans. Research Highlights: This study provides new insights into NALT in S. coeruleoalba.This research deepens the knowledge of the skin of cetaceans. [ABSTRACT FROM AUTHOR]

Simple Summary: Brucella ceti is a marine bacterium that causes neurological, reproductive and skeletal disease in free-ranging cetaceans. Its zoonotic potential and importance for wild animals has prompted, over the years, the search for a reliable diagnostic method to detect antibodies and infer the level of infection. In this work, we perform an exploratory serological study on cetaceans stranded in the Northwestern Mediterranean Sea. Antibody levels were higher in animals with confirmed Brucella disease and infection in juveniles and in animals with chronic morbilliviral infection. This provides the first seroprevalence estimation in this area and reaffirms the active circulation of Brucella in wild cetaceans. Neurobrucellosis in cetaceans, caused by Brucella ceti, is a relevant cause of death in striped dolphins (Stenella coeruleoalba) from the Mediterranean Sea. Serological tests are not used as a routinary technique for the diagnosis of this infection. We briefly describe the pathological findings of nine free-ranging stranded cetaceans diagnosed with Brucella disease or infection in our veterinary necropsy service from 2012 to 2022. The findings included focal diskospondylitis and non-suppurative meningitis, choroiditis and radiculitis. Additionally, an exploratory serological study was conducted in sixty-six frozen sera collected in the period 2012–2022 from fifty-seven striped dolphins, five Risso's dolphins (Grampus griseus), two common bottlenose dolphins (Tursiops truncatus), one common dolphin (Delphinus delphis) and one pilot whale (Globicephala melas) to compare antibody levels in Brucella-infected (n = 8) and non-infected (n = 58) animals, classified by the cause of death, sex, age class and cetacean morbillivirus (CeMV) infection status. The authors hypothesized that active infection in cases of neurobrucellosis would elicit a stronger, detectable humoral response compared to subclinical infections. We performed a commercial competition ELISA (cELISA) using serial serum dilutions for each sample, considering a percentage of inhibition (PI) of ≥40% as positive. A titer of 1:160 was arbitrarily determined as the seropositivity threshold. Seropositive species included striped dolphins and Risso's dolphins. Seroprevalence was higher in animals with neurobrucellosis (87.5%) compared to the overall seroprevalence (31.8%) and to other causes of death, indicating, likely, a high sensitivity but low specificity for neurobrucellosis. Animals with chronic CeMV seemed to have higher seroprevalences, as well as juveniles, which also had a higher disease prevalence. These results indicate, as in other studies, that antibodies are not decisive against clinical brucellosis, although they may indicate a carrier state, and that CeMV may influence Brucella epidemiology. More research is required to elucidate the epidemiology and pathogenesis and to resolve the complicated host–pathogen interaction in Brucella species. [ABSTRACT FROM AUTHOR]

The study of aquatic organisms' ectomorphology is important to understanding the mechanisms of efficient swimming and drag reduction in fish. The drag reduction mechanism in fish remains unknown yet is needed for optimising the efficiency of bionic fish. It is thus crucial to conduct drag tests and analyses. In this paper, an optimal dolphin morphological model is constructed taking the beakless porpoise as the research object. A numerical simulation of the dolphin body model is carried out for different combinations of pitch angle and speed adopting computational fluid dynamics, and the flow field noise of the dolphin body model is solved for different speeds using the FW-H equation. When the dolphin model is oriented horizontally, the differential pressure drag accounts for approximately 20–25% of the total drag as airspeed increases. As both the pitch angle and airspeed increase, the differential pressure drag and friction drag decrease with increasing airspeed. Moreover, the acoustic energy is mainly concentrated at low frequencies for both the dolphin and Bluefin-21 models. The dolphin body model has better noise performance than the Bluefin-21 model at the same speed. The optimisation of the external morphology of the bionic underwater submarine and the analysis of the shape drag are thus important for revealing the drag reduction mechanism, reducing noise in the flow field and provide guidance for research on bionic fish. [ABSTRACT FROM AUTHOR]

Since 1985 a community of wild Atlantic spotted dolphin (Stenella frontalis) have been observed underwater in the Bahamas. A human-worn, acoustic underwater two-way communication interface was developed and deployed from 2013-2016. Dolphins were exposed to an acoustic referentially based wearable underwater computer/interface. A model/rival system was used with dolphins and human participants during in-water sessions. Artificial and natural objects were labeled with computer generated sounds. Female juvenile spotted dolphins dominated the activity. Group size averaged seven dolphins for an average duration of 37 minute over 58 sessions. Of 243 video audio imitations and 56 Cetacean Hearing Augmentation Telemetry (CHAT) audio imitations, six potential response types were documented and measured. Stand-alone vocal contour mimics and Frequency Modulated Contours were the most common imitations. Within 5 sec of a computer-generated sound playing, of the 191 non-stand-alone vocal responses that were produced, 114 of them (59.7%) were judged as partial accurate matches, 3 of them (1.57%) were judged as non-matching partial imitations of a computer-generated sound, 67 of them (35.08%) were signature whistles, and seven of them (3.67%) were either non-signature whistle vocalizations or a mimic of the start or end tones. Thus, the majority of vocalizations produced by the dolphins within five seconds of a computer-generated sound were partial accurate imitations for the computer-generated sound played. Dolphins demonstrated both immediate and delayed vocal imitation and flexible attempts at imitation but did not show signs of a functional understanding of object labels. Atlantic spotted dolphins showed vocal flexibility in reaction to humans broadcasting computer generated sounds.

The ability of the dolphin auditory system to recognize and classify noise signals according to certain invariant characteristics under the influence of noise interference and in conditions of spatial uncertainty of the simultaneous presentation of positive and negative signals was investigated. Bottlenose dolphins trained to differentiate such signals had to solve this problem in conditions simulating real sea conditions, when the perception of a useful noise signal occurs against a background of similar signals and against a noise interference background. First, noise signals were sequentially presented to the animal against a background of white masking noise. Subsequently, the dolphin had to identify a signal of a positive class from several simultaneously sounding sound sources. The animal's performance was assessed at several specified noise interference levels. In this case, the actual noise interference was both white noise and simultaneously sounding negative signals. It has been shown that the efficiency and noise immunity of the dolphin's auditory system depends on the degree of alternativeness of the spatial uncertainty of the simultaneous presentation of signals. [ABSTRACT FROM AUTHOR]

Invasive neuronal tract-tracing is not permitted in very large or endangered animals. This is especially the case in marine mammals like dolphins. Diffusion-weighted imaging of fiber tracts could be an alternative if feasible even in brains that have been fixed in formalin for a long time. This currently is a problem, especially for detecting crossing fibers. We applied a state-of-the-art algorithm of Diffusion-weighted imaging called Constrained Spherical Deconvolution on diffusion data of three fixed brains of bottlenose dolphins using clinical human MRI parameters and were able to identify complex fiber patterns within a voxel. Our findings indicate that in order to maintain the structural integrity of the tissue, short-term post-mortem fixation is necessary. Furthermore, pre-processing steps are essential to remove the classical Diffusion-weighted imaging artifacts from images: however, the algorithm is still able to resolve fiber tracking in regions with various signal intensities. The described imaging technique reveals complex fiber patterns in cetacean brains that have been preserved in formalin for extended periods of time and thus opens a new window into our understanding of cetacean neuroanatomy. • Importance of non-invasive study of large brains • DWI data analysis using the CSD technique to get crossing fibers through the dolphin brain • Data preprocessing steps overcome the tissue abnormality of the postmortem brain. [ABSTRACT FROM AUTHOR]

Background: To tag large marine vertebrates, without the need to catch them, avoiding using barbs for tag retention, and precisely controlling tag location, the remote Tag Attachment Device on a pole (TADpole) was developed. This allows single-pin tags (Finmount, Wildlife Computers) to be attached to the dorsal fins of free-swimming large marine vertebrates. Results: TADpole comprises a pole-mounted holster that carries a tag. It uses compressed air, and a micro-controller, to rapidly insert a stainless-steel pin through a corrodible metal retaining ring in the first tag attachment wing, the animal’s dorsal fin, and then a press fit Delrin retaining ring in the tag wing on the other side of the fin. Tagging only occurs when the trailing edge of the dorsal fin touches a trigger bar in the holster, ensuring optimal pin placement. It was developed using fins from cadavers, then trialed on briefly restrained coastal dolphins that could be followed in successive days and weeks, and then on free-swimming animals in the field. The latter showed very short touch/response intervals and highlighted the need for several iterative revisions of the pneumatic system. This resulted in reducing the total time from triggering to tag application to ~ 20 ms. Subsequent efforts expanded the TADpole’s applicability to sharks. One free-swimming Atlantic spotted dolphin, two white sharks, and one whale shark were then tagged using the TADpole. Conclusions: Being able to tag free-swimming dolphins and sharks remotely and precisely with satellite-linked telemetry devices may contribute to solving conservation challenges. Sharks were easier to tag than dolphins. Dolphin touch-to-response times were 28 ms or less. Delphinid skin has unique polymodal axon bundles that project into the epidermis, perhaps a factor in their uniquely fast response, which is 10 × faster than humans. Their primary reaction to tagging is to abduct the flippers and roll the fin out of the TADpole holster. This device has the potential to deliver high-quality tag data from large vertebrates with dorsal fins without the stress and logistics associated with catch-and-release, and without the trauma of tags that use barbs for retention. It also collects a dorsal fin biopsy core. [ABSTRACT FROM AUTHOR]

Imitating Dolphin fish-like movement is productive method for enhancing their hydrodynamic capabilities. This work aims to analyze and understand the oscillations of tail fluke of Dolphin, which can be used as a propulsive mechanism for underwater fish robots and vehicles. The objective of the work is to achieve the desired oscillating amplitude by simulating the NACA 0012 profile using computational models and Set up the swimming movement of the dolphin, imitating a fish like model. Computational techniques were employed to examine the propulsive capabilities of the oscillating hydrofoil, inspired by the dolphin's biological propulsion. The evolutionary of fluid pattern in the field surrounding both Dolphin fish model and the NACA0012 hydrofoil, from initial motion to cruising, was established, and the hydrodynamic impact was subsequently studied. An user-defined function (UDF) was developed to create a dynamic mesh interface with CFD code ANSYS FLUENT for establishing the oscillations of Dolphin tail across the flow field. Influencing hydrodynamic coefficients such as lift and drag coefficients at different frequencies were also obtained. The findings shown that when the acceleration of the Dolphin fish model increases, the time averaged drag force coefficient drops because The wake field's vortex disperses to have some beneficial effects and pressure of water surrounding the fish head intensifies to produce a large resistance force. Simulation results show a 98% agreement at lower frequency and speed levels but a 5% deviation at higher frequency and speed due to turbulence effects in both models. It was established that the vortex superposition enhances the Dolphin fish like model rather than lowering its positive impacts. The Strouhal number, which is obtained by the fluid field's evolution rule, can be linked to the Kármán vortex street span with reverse. [ABSTRACT FROM AUTHOR]

Given the increased extraction of trace elements for use by new and emerging technologies, monitoring the environmental fate and potential effects of these compounds within the aquatic environment has never been more critical. Here, hepatic trace element concentrations were assessed in a key sentinel predator, the common dolphin (Delphinus delphis), using a long-term dataset. Variation in concentrations were assessed in relation to other elements, time period, decomposition state, sex, age, total body length, sexual maturity and nutritional status, and cause of death. Additionally, mercury toxicity thresholds for evaluating risk were reviewed and employed. Concentrations of elements which bioaccumulate, THg, MeHg, Cd, and Pb, in addition to Se and V, were strongly correlated with age, and/or body length. An association was observed between Zn concentrations and disease status, with significantly higher concentrations measured in individuals that died from infectious disease, compared to other causes. Strong inter-elemental relationships were detected, namely between Hg and Se, MeHg and Se, Cd and Se, and Cu and Zn. While THg:Se molar ratio values were observed to increase with age and body length, approaching equimolarity. THg was largely comprised of inorganic Hg in older individuals, potentially bound to Se, therefore the effects from THg toxicity may possibly be less important than originally assumed. In contrast, higher MeHg:Hg ratio values were reported in juveniles, suggesting a poorer efficiency in demethylation and a higher sensitivity. The generation of data on proportions of hepatic MeHg and inorganic Hg is highly informative to both future toxicity threshold assessments within pollutant indicator assessments, and to understanding the ultimate fate of mercury in the marine web.

Nowadays, an increase in the number of marine species at risk of extinction has been observed. Therefore, studies on the reproductive characteristics of these animals are essential. This animal is considered relatively rare, and there is scarce information regarding its reproductive biology and physiology. Thus, this study aims to describe the morphology and morphometry of sperm obtained from dwarf sperm whale. The material used in this work was collected during the necropsy of a dwarf sperm whale specimen. Thus, seminal samples were fixed and stained with panoptic stain. In morphometric analysis, the results obtained were: acrosome length of 0.83±0.01 μm, head length of 1.5±0.02 μm, intermediate part of 0.4±0.00 μm and total length of 27.3±0.51 μm. In terms of morphology, the defects observed were double head, heavily curled tail, abnormal small head, simply bent tail, piriform head, heavily bent tail and specimens within the normal range. In this context, the morphometric and morphological sperm analysis of Kogia sima described in this study can assist future studies regarding the reproductive physiology of these animals.

The dolphin motif on the ship-shaped oil lamp treasured in the Museum of Smederevo (4th century AD) has complex iconography, multi-layered and complex symbolism, and a long history. This article presents and explains how its iconography and meaning were gradually formed and developed in ancient Greek and Roman art, as well as the peculiarities of its gradual transformation into a Christian symbol. It is found that the context of the appearance of the dolphin motif in art during different epochs is not a mere coincidence, but the expression of a clear intention on the part of particularly learned artists and commissioners of works of art. Since there are no written records of this motif that would explain its iconography and meaning, and since the motif itself is by nature very hermetic, and at the same time very rare, the characteristic context of the appearance of the dolphin motif in art is also a decisive parameter for analyzing its meaning and its gradual formation.

Nature, mainly the wetland ecosystem services, is the predominant tourist attraction worldwide. This study conducted a choice modeling method based on environmental attributes contributing to nature-based tourism for preserving the quality of the wetland ecosystem in Govater Bay and Hur-e-Bahu international wetland (GIW) in southeastern Iran. Besides inclusion in the Ramsar Convention on Wetlands, the GIW is particularly interesting because it hosts various valuable aquatic species, such as mangrove forests (Avicennia marina), migratory birds, dolphins, and turtles. According to the results, if the current condition of the GIW ecosystem continues, public participation will decrease as unwillingness to pay for environmental conservation purposes. It was also found that educated visitors are willing to pay more for GIW conservation policy options compared to less-educated ones. Consequently, concerning the visitors’ perception, the “Dolphin Observability (DO)” has the highest conservation (existence) value, followed by the natural landscape of Mangrove forest coverage (NW) in the second rank. Finally, some suggestions and development strategies are provided based on the empirical findings to improve the sustainability and conservation of the GIW ecosystem.

Abstract Researchers can investigate many aspects of animal ecology through noninvasive photo–identification. Photo–identification is becoming more efficient as matching individuals between photos is increasingly automated. However, the convolutional neural network models that have facilitated this change need many training images to generalize well. As a result, they have often been developed for individual species that meet this threshold. These single‐species methods might underperform, as they ignore potential similarities in identifying characteristics and the photo–identification process among species. In this paper, we introduce a multi‐species photo–identification model based on a state‐of‐the‐art method in human facial recognition, the ArcFace classification head. Our model uses two such heads to jointly classify species and identities, allowing species to share information and parameters within the network. As a demonstration, we trained this model with 50,796 images from 39 catalogues of 24 cetacean species, evaluating its predictive performance on 21,192 test images from the same catalogues. We further evaluated its predictive performance with two external catalogues entirely composed of identities that the model did not see during training. The model achieved a mean average precision (MAP) of 0.869 on the test set. Of these, 10 catalogues representing seven species achieved a MAP score over 0.95. For some species, there was notable variation in performance among catalogues, largely explained by variation in photo quality. Finally, the model appeared to generalize well, with the two external catalogues scoring similarly to their species' counterparts in the larger test set. From our cetacean application, we provide a list of recommendations for potential users of this model, focusing on those with cetacean photo–identification catalogues. For example, users with high quality images of animals identified by dorsal nicks and notches should expect near optimal performance. Users can expect decreasing performance for catalogues with higher proportions of indistinct individuals or poor quality photos. Finally, we note that this model is currently freely available as code in a GitHub repository and as a graphical user interface, with additional functionality for collaborative data management, via Happywhale.com.

In the western North Pacific, prominent granulomatous testes have been detected in many Brucella-infected common minke whales (Balaenoptera acutorostrata), but there have been no reports in toothed cetaceans. We found severe orchitis with granulomatous lesions in a rough-toothed dolphin (Steno bredanensis) stranded on the Pacific coast of Japan in 2011. Histopathological examination revealed leukocyte infiltration of the lesions. DNA from the lesion was analyzed by PCR and it showed molecular biological similarities with those of Brucella-infected common minke whales and Brucella ceti of sequence-type 27 (ST27). These results suggest that the type of Brucella ceti that infected the dolphin was ST27, which may have caused severe orchitis. This study adds to our understanding of Brucella infections in marine mammals. [ABSTRACT FROM AUTHOR]

Bottlenose dolphins (Tursiops truncatus) rely on frequency- and amplitude-modulated whistles to communicate, and noise exposure can inhibit the success of acoustic communication through masking or causing behavioral changes in the animal. At the US Navy Marine Mammal Program (MMP) in San Diego, CA, dolphins are housed in netted enclosures in the San Diego Bay and exposed to noise from vessels, unmanned underwater vehicles, and other remote sensing devices. The acoustic behavior of 20 dolphins was monitored and whistle rates during noise events were quantified. Whistle rates during the onset of the event (i.e., the first 5 min) did not significantly differ from the pre-onset (5 min immediately preceding). Whistle rates were also not significantly different for the entire duration of the event compared to a matched control period. The noise's frequency range (i.e., control, mid-frequency (0–20 kHz) or high-frequency (21–80 kHz)), signal-to-noise ratio, and sound pressure level were not significantly related to the dolphins' whistle rate. Considering this is a location of frequent and moderate noise output, these results lend support to established guidelines on anthropogenic noise exposure for cetaceans, suggesting that moderate noise exposure levels may not impact communication efforts in bottlenose dolphins. [ABSTRACT FROM AUTHOR]

Timely detection and understanding of causes for population decline are essential for effective wildlife management and conservation. Assessing trends in population size has been the standard approach, but we propose that monitoring population health could prove more effective. We collated data from 7 bottlenose dolphin (Tursiops truncatus) populations in the southeastern United States to develop a method for estimating survival probability based on a suite of health measures identified by experts as indices for inflammatory, metabolic, pulmonary, and neuroendocrine systems. We used logistic regression to implement the veterinary expert system for outcome prediction (VESOP) within a Bayesian analysis framework. We fitted parameters with records from 5 of the sites that had a robust network of responders to marine mammal strandings and frequent photographic identification surveys that documented definitive survival outcomes. We also conducted capture–mark–recapture (CMR) analyses of photographic identification data to obtain separate estimates of population survival rates for comparison with VESOP survival estimates. The VESOP analyses showed that multiple measures of health, particularly markers of inflammation, were predictive of 1‐ and 2‐year individual survival. The highest mortality risk 1 year following health assessment related to low alkaline phosphatase (odds ratio [OR] = 10.2 [95% CI: 3.41–26.8]), whereas 2‐year mortality was most influenced by elevated globulin (OR = 9.60 [95% CI: 3.88–22.4]); both are markers of inflammation. The VESOP model predicted population‐level survival rates that correlated with estimated survival rates from CMR analyses for the same populations (1‐year Pearson's r = 0.99, p = 1.52 × 10–5; 2‐year r = 0.94, p = 0.001). Although our proposed approach will not detect acute mortality threats that are largely independent of animal health, such as harmful algal blooms, it can be used to detect chronic health conditions that increase mortality risk. Random sampling of the population is important and advancement in remote sampling methods could facilitate more random selection of subjects, obtainment of larger sample sizes, and extension of the approach to other wildlife species. [ABSTRACT FROM AUTHOR]

Cetaceans, which are integral to marine ecosystems, face escalating anthropogenic threats, including climate change and pollution, positioning them as critical sentinel species for ocean and human health. This review explores the neglected realm of non-Candida yeasts in cetaceans, addressing the gaps in the understanding of their prevalence, pathogenicity, and environmental impacts. By examining identified species such as Cryptococcus spp., Paracoccidioides spp., and several dimorphic fungi, this review emphasizes global prevalence, epidemiology and ecology, pathogenicity, and potential zoonotic implications. It also discusses the fine line between yeast commensalism and pathogenicity by considering environmental influences such as pollution, climate shifts, and immune suppression. Environmental impact discussions delve into how rising ocean temperatures and pollution can modify yeast mycobiota, potentially affecting marine host health and broader ecosystem dynamics. The cetacean's unique physiology and ecological niches are considered, highlighting potential impacts on behaviors, reproductive success, and survival rates. Identifying crucial knowledge gaps, the review calls for intensified research efforts, employing advanced molecular techniques to unravel the cetacean mycobiome. Systematic studies on yeast diversity, antifungal susceptibility, and their influence on environmental and ecosystem health are proposed, and the balance between commensal and pathogenic species emphasizes the significance of the One Health approach. In conclusion, as marine mammals face unprecedented challenges, unveiling non-Candida yeasts in cetaceans emerges as a critical endeavor with far-reaching implications for the conservation of marine ecosystems and for both animal and human public health. [ABSTRACT FROM AUTHOR]

This research aimed at analysing the prioritization strategies used in developing sustainable dolphin-watching tourism at Lovina Beach. The study was conducted at Lovina Beach by involving five informants who were selected by using purposive sampling as the research subjects. They were a government, boat driver, villager, academician, and tourist. The data were obtained through FGD (focus group discussion), observation, interview, and document analysis. The instruments used were observation sheet, interview guide, and note list. The SWOT (strength, weakness, opportunity, and threat), and AHP (analytical hierarchy process). The data were also interpreted quantitatively. The results showed that; there were five criteria used in obtaining the prioritization strategies implemented in developing dolphin watching tourism sustainably. Those criteria were; human resource readiness, cost advantage, urgency, risk, and differentiation. It was found out that the prioritized strategies were; coaching and socializing, increasing local communities’ awareness, empowering the management of rubbish and waste, diversifying and developing Another finding revealed that internal and external factors influenced the development itself. [ABSTRACT FROM AUTHOR]

The morphological differentiation between coastal and offshore ecotypes of bottlenose dolphins (genus Tursiops) has been researched since the 1960s, particularly in T. truncatus (Montagu, 1821), although most morphological studies have focused on localized populations. Therefore, it is unclear how patterns observed in these individual populations integrate within the global morphological variation. Here we carry out a meta‐analysis of global morphological variation between coastal and offshore ecotypes from 532 museum specimens, using both linear measurements (LM; 282 specimens), and shape data using geometric morphometrics (GM; 290 specimens). Together these analyses show consistent differentiation in skull morphology between coastal and offshore ecotypes, and provide a detailed description of variation patterns within each ecotype. These patterns show high individual morphological variation in the coastal ecotype between locations, while the offshore ecotype appears morphologically more uniform across the areas sampled. Overall, most skull shape variation can be described by features noticeable dorsally in the structures of the rostrum, whereas more limited change was found in ventral traits. Our results suggest that individual coastal populations may vary according to local environmental conditions, while those corresponding to the offshore ecotype appear to share similar morphological characteristics that might increase fitness in offshore habitats. [ABSTRACT FROM AUTHOR]

Nowadays, an increase in the number of marine species at risk of extinction has been observed. Therefore, studies on the reproductive characteristics of these animals are essential. This animal is considered relatively rare, and there is scarce information regarding its reproductive biology and physiology. Thus, this study aims to describe the morphology and morphometry of sperm obtained from dwarf sperm whale. The material used in this work was collected during the necropsy of a dwarf sperm whale specimen. Thus, seminal samples were fixed and stained with panoptic stain. In morphometric analysis, the results obtained were: acrosome length of 0.83±0.01 μm, head length of 1.5±0.02 μm, intermediate part of 0.4±0.00 μm and total length of 27.3±0.51 μm. In terms of morphology, the defects observed were double head, heavily curled tail, abnormal small head, simply bent tail, piriform head, heavily bent tail and specimens within the normal range. In this context, the morphometric and morphological sperm analysis of Kogia sima described in this study can assist future studies regarding the reproductive physiology of these animals. [ABSTRACT FROM AUTHOR]

The transboundary area of the Strait of Gibraltar is home to seven protected cetacean species that are threatened by high intensity of maritime traffic. More comprehensive knowledge of cetaceans and maritime traffic is required, together with analyses of legislations, strategies and policies.This study quantitatively investigates cetacean distribution and maritime traffic intensity and, for the species of community interest bottlenose dolphin, habitat suitability. Results are qualitatively discussed considering the overlap of cetacean hot spots with different maritime activities and the consistency of spatial conservation management measures in force.The Fixed Line Transect Mediterranean Monitoring Network protocols were followed for 59 visual surveys using ferries as observation platforms for monitoring cetaceans and maritime traffic. Surveys were carried out along the transects between Algeciras and Ceuta and between Algeciras and Tanger‐Med, in 2018 and 2019. 264 cetacean sightings, including seven different species and four near‐miss collision events (involving pilot, sperm and fin whales), were reported.Monitoring cetaceans from ferries in the Strait provided insights into cetacean distribution and maritime traffic, enabling the identification of cetacean hot spots, suitable habitats and maritime traffic high‐risk zones.A transboundary management effort is required, together with an adaptive approach for protecting highly mobile species such as cetaceans. Proposals include a long‐term cetacean monitoring program carried out by dedicated observers on board ferries as a cost‐effective methodology and mandatory training for crew members, to increase cetacean knowledge and reduce collision risk.The designation of an international temporal or, in some zones, permanent speed reduction area (i.e., Cetacean Critical Navigation Zone, with a maximum speed of 13 knots) and of a micro‐sanctuary with a seasonal no‐take zone in the Bay between Algeciras and Gibraltar, together with international surveillance, are recommended measures for the enhancement of conservation efforts in the Strait. [ABSTRACT FROM AUTHOR]

This study identified the overlap between artisanal fishing areas and the Franciscana dolphin (Pontoporia blainvillei) in the Southwest Atlantic Ocean (SWAO), Brazil, to identify areas where the species was incidentally captured from the perception of artisanal fishers. Using a semistructured questionnaire, ethnographic interviews (n = 330) were carried out from 2012 to 2018 with fishers from ten communities in southeastern (ES and RJ) and southern (PR) Brazil. After the interviews, the fishers presented their fishing routes, locations and areas of incidental capture and occurrence of the Franciscana dolphin. Ninety-five fishers (29%) identified the species: 23 in northern ES, 1 in southern ES, 20 in northern RJ, and 51 in the PR. Among the 235 fishers who could not identify the species, approximately half worked in the distribution gaps. The areas of occurrence noted by the fishers coincided with those described in the “National Action Plan for the Conservation of the Toninha,” an official document from the Brazilian Government and scientific literature. The results indicate that the information provided by fishers is useful for understanding the distribution of the Franciscana dolphin and can be used in the development of management strategies to mitigate the incidental capture of the species. [ABSTRACT FROM AUTHOR]

The study of aquatic organisms’ ectomorphology is important to understanding the mechanisms of efficient swimming and drag reduction in fish. The drag reduction mechanism in fish remains unknown yet is needed for optimising the efficiency of bionic fish. It is thus crucial to conduct drag tests and analyses. In this paper, an optimal dolphin morphological model is constructed taking the beakless porpoise as the research object. A numerical simulation of the dolphin body model is carried out for different combinations of pitch angle and speed adopting computational fluid dynamics, and the flow field noise of the dolphin body model is solved for different speeds using the FW-H equation. When the dolphin model is oriented horizontally, the differential pressure drag accounts for approximately 20–25% of the total drag as airspeed increases. As both the pitch angle and airspeed increase, the differential pressure drag and friction drag decrease with increasing airspeed. Moreover, the acoustic energy is mainly concentrated at low frequencies for both the dolphin and Bluefin-21 models. The dolphin body model has better noise performance than the Bluefin-21 model at the same speed. The optimisation of the external morphology of the bionic underwater submarine and the analysis of the shape drag are thus important for revealing the drag reduction mechanism, reducing noise in the flow field and provide guidance for research on bionic fish.

The paper deals with the representation of Arion on the monumental floor mosaic in one of the most representative rooms of the Roman Villa del Casale in Sicily, dating from the beginning of the 4th century (fig. 1, 2). It is special in many respects. It is the most monumental and magnificent representation of Arion in ancient art. Arion is depicted in the central part of а complex mosaic consisting of many scenes, figures and motifs. He is sitting on a dolphin and playing music on his instrument. The dolphin motif in this scene is unique and not examined in the literature, leaving much room for research. To our knowledge, it is a unique example of a dolphin ridden by Arion, shown hunting its prey, which is certainly not a coincidence or a descriptive detail of the artist, but a reflection of his knowledge and the clear intention of the patrons of the mosaic. On the contrary, this detail subtly explains the meaning of the entire mosaic illustrating the story of Arion and the reasons for his appearance. It suggests that the owners of the villa either belonged to the highest Roman aristocracy of their time, or perhaps were even related to the imperial family. By examining the history of the specific dolphin motif it is shown that this detail bears the symbolism of victory, thus, corresponding to the meaning of the Arion mosaic and other mosaics in Villa del Casale.

Background: A highly pathogenic avian influenza (HPAI) A (H5N1) virus has been detected in domestic and wild animals worldwide. The incidence of HPAI infections in sea mammals has been increasing, as is the number of stranded marine mammals linked to H5N1 viral clade 2.3.4.4(b). In this study, we investigated a stranding event involving dolphins and human–dolphin contact, and investigated the potential risk of animal-to-human H5N1 transmission with a survey of exposure on the Tsurigasaki coast, Japan. Methods: We performed a non-random, convenient-sample-based, survey on Tsurigasaki beach where around 30 melon-headed whales were stranded on April 3, 2023. Face-to-face (n = 25) and telephone (n = 1) interviews among surfers took place on April 7 and 8. A nasal swab for quick antigen testing was taken from those who wished to be tested (n = 13), to detect infections with influenza A virus. Results: Although there was no confirmatory diagnosis of H5N1 in either humans or dolphins (while n = 3 dolphins were autopsied), we found that a large number of surfers had touched the dolphins with their bare hands while attempting to rescue them, and that some surfers were directly exposed to dolphin blood and body fluids in the ocean. Conclusions: The adequate communication of risk is required to minimize the threat of viral transmission at this particular human–animal interface. Administrative and legal responses to cross-species transmission, including guidelines via one health frameworks, a rapid evaluation process of ethical approval, and the systematic involvement of experts in infectious disease, must be urgently formulated.

Cetacea is a clade well-adapted to the aquatic lifestyle, with diverse adaptations and physiological responses, as well as a robust antioxidant defense system. Serious injuries caused by boats and fishing nets are common in bottlenose dolphins (Tursiops truncatus); however, these animals do not show signs of serious infections. Evidence suggests an adaptive response to tissue damage and associated infections in cetaceans. Heme oxygenase (HO) is a cytoprotective protein that participates in the anti-inflammatory response. HO catalyzes the first step in the oxidative degradation of the heme group. Various stimuli, including inflammatory mediators, regulate the inducible HO-1 isoform. This study aims to characterize HO-1 of the bottlenose dolphin in silico and compare its structure to the terrestrial mammal protein. Upstream HO-1 sequence of the bottlenose dolphin was obtained from NCBI and Ensemble databases, and the gene structure was determined using bioinformatics tools. Five exons and four introns were identified, and proximal regulatory elements were detected in the upstream region. The presence of 10 α-helices, three 310 helices, the heme group lodged between the proximal and distal helices, and a histidine-25 in the proximal helix serving as a ligand to the heme group were inferred for T. truncatus. Amino acid sequence alignment suggests HO-1 is a conserved protein. The HO-1 "fingerprint" and histidine-25 appear to be fully conserved among all species analyzed. Evidence of positive selection within an α-helix configuration without changes in protein configuration and evidence of purifying selection were found, indicating evolutionary conservation of the coding sequence structure.

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Wetland ecosystem services, are one of the predominant tourist attraction worldwide. This study conducted a choice modeling method based on environmental attributes contributing to naturebased tourism for preserving the quality of the wetland ecosystem in Govater Bay and Hur-e-Bahu international wetland (GIW) in southeastern Iran. Besides inclusion in the Ramsar Convention on Wetlands, the GIW is particularly interesting as it hosts various valuable flora and fauna species, such as mangrove forests (Avicennia marina), migratory birds, dolphins, and turtles. According to the results, if the current condition of the GIW ecosystem continues, public participation will decrease shown by unwillingness of ecotourists to pay for environmental conservation purposes. It was also found that higher educated visitors are willing to pay more for GIW conservation policy options compared to less educated ones. Based on the visitors' opinion, the "Dolphin Observability (DO)" had the highest conservation (existence) value, followed by the natural landscape of Mangrove forest coverage (NW). Some suggestions and development strategies are delivered based on the empirical findings to improve the sustainability and conservation of the GIW ecosystem. [ABSTRACT FROM AUTHOR]

International trade in croaker swim bladders or maws and incidental catches in fisheries targeting croakers for their maws pose a global problem that needs addressing to protect target croakers and globally threatened small cetaceans, sharks, rays and marine turtles.The lesson of the likely imminent extinction of the vaquita porpoise (Phocoena sinus) in the Gulf of California, Mexico, owing to entanglement in gillnets targeting the totoaba croaker for its maw, is that the underlying threats to marine species must be addressed well before precipitous declines make their extinction inevitable.Opportunistic interviews with fishers and fish traders in Bangladesh indicate that the increasing demand for fish maws, selling for as much as 5,000 USD per kg, may be intensifying small‐scale coastal fisheries and bycatches of globally threatened marine wildlife, especially due to the potential for a windfall profit.In 137 croaker catches made in gillnets, sharks were bycaught in 22%, marine turtles in 8% and rays in 3% of catches. Of particular concern were six bycatches of 125 Critically Endangered scalloped hammerhead sharks (Sphyrna lewini), 11 bycatches of 20 Vulnerable (VU) olive ridley turtles (Lepidochelys olivacea) and two bycatches of 13 VU longtail butterfly rays (Gymnura poecilura).A recent IUCN Motion for 'Controlling and monitoring trade in croaker swim bladders to protect target croakers and reduce incidental catches of threatened marine megafauna' recommends conducting an analysis on the impacts of the demand for and trade in fish maws on croaker species and threatened marine megafauna, regulating trade in fish maws through national laws and developing a potential proposal to list croaker species in the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).To prevent species extinctions, additional measures focusing on fishery management will be needed. [ABSTRACT FROM AUTHOR]

Cetaceans are well known for their remarkable cognitive abilities including self-recognition, sound imitation and decision making. In other mammals, the prefrontal cortex (PFC) takes a key role in such cognitive feats. In cetaceans, however, a PFC could up to now not be discerned based on its usual topography. Classical in vivo methods like tract tracing are legally not possible to perform in Cetacea, leaving diffusion-weighted imaging (DWI) as the most viable alternative. This is the first investigation focussed on the identification of the cetacean PFC homologue. In our study, we applied the constrained spherical deconvolution (CSD) algorithm on 3 T DWI scans of three formalin-fixed brains of bottlenose dolphins (Tursiops truncatus) and compared the obtained results to human brains, using the same methodology. We first identified fibres related to the medio-dorsal thalamic nuclei (MD) and then seeded the obtained putative PFC in the dolphin as well as the known PFC in humans. Our results outlined the dolphin PFC in areas not previously studied, in the cranio-lateral, ectolateral and opercular gyri, and furthermore demonstrated a similar connectivity pattern between the human and dolphin PFC. The antero-lateral rotation of the PFC, like in other areas, might be the result of the telescoping process which occurred in these animals during evolution. [ABSTRACT FROM AUTHOR]

Cold agglutinin disease, one of the serological classifications of immune-mediated hemolytic anemia, is caused by the production of autoantibodies that react with erythrocytes at low temperatures. A captive bottlenose dolphin presented with regenerative and hemolytic anemia. Anticoagulated whole blood was agglutinated at room temperature (approximately 18°C), with reversal of agglutination on warming to 37°C, indicating the presence of cold agglutinin. Based on these findings, this animal was diagnosed with cold agglutinin disease. Clindamycin, doxycycline, and prednisolone were administered orally to treat the infection and immune-mediated hemolytic anemia. Anemia gradually improved after initiation of pharmacotherapy, and erythrogenesis slowed as erythroblasts disappeared and reticulocyte count decreased in peripheral blood. This represents the first report of cold agglutinin disease in a cetacean. [ABSTRACT FROM AUTHOR]