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Cetaceans have evolved unique limb structures, such as flippers, due to genetic changes during their transition to aquatic life. However, the full understanding of the genetic and evolutionary mechanisms behind these changes is still developing. By examining 25 limb-related protein-coding genes across various mammalian species, we compared genetic changes between aquatic mammals, like whales, and other mammals with unique limb structures such as bats, rodents and elephants. Our findings revealed significant modifications in limb-related genes, including variations in the Hox, GDF5 and Evx genes. Notably, a relaxed selection in several key genes was observed, suggesting a lifting of developmental constraints, which might have facilitated the emergence of morphological innovations in cetacean limb morphology. We also uncovered non-synonymous changes, insertions and deletions in these genes, particularly in the polyalanine tract of HOXD13, which are distinctive to cetaceans or convergent with other aquatic mammals. These genetic variations correlated with the diverse and specialized limb structures observed in cetaceans, indicating a complex interplay of relaxed selection and specific mutations in mammalian limb evolution. [ABSTRACT FROM AUTHOR]

This document is a compilation of references and citations from scientific papers and reports on various aspects of southern right whales (Eubalaena australis). The sources cover topics such as historical records of the whales in Argentina, their feeding grounds, population increases in southern Brazil, gray whale behavior and prey, and the recovery of the whales at South Georgia. The document also includes references to studies on the distribution, habitat selection, and prey sources of southern right whales, as well as past catches of these whales by the Soviet Union. This information provides valuable insights for researchers and conservationists studying and working to protect southern right whales. [Extracted from the article]

This article, published in Aquatic Mammals, discusses the tracking of a white humpback whale in the eastern South Pacific. The study focuses on the first-year survival of a white humpback whale, which is a rare occurrence in nature. The researchers document and analyze sightings of the whale in Costa Rica, Peru, and Antarctica, providing valuable insights into the migratory movements of the species in the region. The document also discusses the rarity of hypopigmented cetaceans and the challenges they face due to their coloration. The authors encourage long-term observation of the whale and other cetaceans using citizen science and social media. Additionally, there is a list of references related to humpback whales, covering topics such as their breeding cycle, migration patterns, entanglement in fishing gear, and sightings of white or leucistic individuals. These references provide valuable information for researchers studying humpback whales and their conservation, as well as for individuals interested in learning more about these majestic creatures. [Extracted from the article]

This article discusses an observation of killer whales harassing humpback whales in offshore Brazilian waters. The observation took place in August 2023 and involved killer whales chasing and surrounding the humpback whales, with instances of physical contact. The behavior suggests that the killer whales may be targeting the humpback whales as prey. While fatal attacks are rare, there have been reports of such attacks in different regions of the world. The article also mentions that killer whales generally target smaller or younger whales during attacks. The observations provide new insights into the interactions between killer whales and humpback whales in the region, but it is unclear if these interactions have increased or are being recorded more frequently due to improved technology. This collection of scientific articles explores various aspects of killer whale interactions with other marine species in different regions, providing valuable insights into their behavior and ecological implications. These findings contribute to our understanding of the complex relationships between marine species and can inform conservation efforts. [Extracted from the article]

Insular evolution on archipelagos generates a significant proportion of global biodiversity, yet islands are among the ecosystems most sensitive to accelerating anthropogenic disturbance, introductions of non‐native species, and emerging pathogens, among other conservation challenges. The Alexander and Haida Gwaii archipelagos along North America's North Pacific Coast support a disproportionate number of endemic taxa compared to other high‐latitude terrestrial ecosystems. In this region, endemics in Canada are explicitly protected, but in the United States, endemics have been operationally ignored. We reviewed regional research on terrestrial mammals and endemics from 2000–2022 to guide wildlife management. Elevated regional endemism is due to a combination of deep and shallow temporal processes (i.e., long‐term refugial isolation vs. recent colonization). With adequate sampling, genomic analyses are well‐suited to identifying nuanced patterns of divergence and endemism, thereby facilitating a deeper understanding of regional diversity. We identified 18 mammalian endemics in Southeast Alaska, USA, at varying taxonomic scales, but research effort has significant taxonomic biases and sampling infrastructure remains inadequate. Of the 66 terrestrial and aquatic mammal species in Southeast Alaska, only 55% are represented by ≥10 archived samples over the last 2 decades. Across taxa, major spatial and temporal sampling gaps limit interpretations of wildlife responses to changing environmental conditions. The Tongass National Forest is spread across an island archipelago, and climate change is projected to have disproportionate impacts on island endemics worldwide. In this case, the United States Forest Service is not closely monitoring endemic taxa, as was required by the Tongass Land Management Plan in 1997. Our review underscores a need for increased consideration of how endemism can be incorporated into land and wildlife management across the Alexander Archipelago. Moving forward, we encourage state and federal agencies, Indigenous communities, and international collaborators to continue to partner with natural history biorepositories to ensure strategic wildlife sampling infrastructure is built and made accessible to the broader scientific community as part of the land management process. [ABSTRACT FROM AUTHOR]

Aquatic mammals in Indonesia are officially protected. However, there is a lack of research on these mammals, particularly in relation to potential diseasecausing bacteria. A study was conducted in a conservation pond to address this gap, where swab samples were taken from the blowholes of aquatic mammals. The focus was on identifying bacteria that could potentially cause infectious diseases in these animals. The results revealed V. parahaemolyticus bacterial isolates, which showed a 98% similarity to the registered V. parahaemolyticus in NCBI. These bacterial isolates exhibited hemolysin properties and demonstrated resistance to trimethoprim, streptomycin, cephalothin, and penicillin antibiotics. [ABSTRACT FROM AUTHOR]

Simple Summary: In this work, we documented the presence of two neurotrophins NGF (Nerve Growth Factor) and BDNF (Brain-Derived Neurotrophic Factor) in the pancreas of two species of marine mammals, Tursiops truncatus (common bottlenose dolphin) and Otaria flavescens (South American sea lion). Pancreas samples were provided by the Mediterranean Marine Mammal Tissue Bank of the Department of Comparative Biomedicine and Food Science of the University of Padua (Italy). These two growth factors are well-known mediators for maintaining the survival of neurons but also exert a metabotrophic effect. The localization in the pancreas of bottlenose dolphins and sea lions of these neurotrophins could help to better understand how these marine animals handle metabolic challenges in their adaptation to ocean life. In this study, we have investigated the immunolocalization of NGF (Nerve Growth Factor) and BDNF (Brain-Derived Neurotrophic Factor) in the pancreas of two species of marine mammals: Tursiops truncatus (common bottlenose dolphin), belonging to the order of the Artiodactyla, and Otaria flavescens (South American sea lion), belonging to the order of the Carnivora. Our results demonstrated a significant presence of NGF and BDNF in the pancreas of both species with a wide distribution pattern observed in the exocrine and endocrine components. We identified some differences that can be attributed to the different feeding habits of the two species, which possess a different morphological organization of the digestive system. Altogether, these preliminary observations open new perspectives on the function of neurotrophins and the adaptive mechanisms of marine mammals in the aquatic environment, suggesting potential parallels between the physiology of marine and terrestrial mammals. [ABSTRACT FROM AUTHOR]

The increased limb bone density documented previously for aquatic tetrapods has been proposed to be an adaptation to overcome buoyancy during swimming and diving. It can be achieved by increasing the amount of bone deposition or by reducing the amount of bone resorption, leading to cortical thickening, loss of medullary cavity, and compaction of trabecular bone. The present study examined the effects of locomotor habit, body size, and phylogeny on the densitometric, cross-sectional, and biomechanical traits of femoral diaphysis and neck in terrestrial, semiaquatic, and aquatic carnivores, and in terrestrial and semiaquatic rodents (12 species) by using peripheral quantitative computed tomography, three-point bending, and femoral neck loading tests. Groupwise differences were analyzed with the univariate generalized linear model and the multivariate linear discriminant analysis supplemented with hierarchical clustering. While none of the individual features could separate the lifestyles or species adequately, the combinations of multiple features produced very good or excellent classifications and clusterings. In the phocid seals, the aquatic niche allowed for lower femoral bone mineral densities than expected based on the body mass alone. The semiaquatic mammals mostly had high bone mineral densities compared to the terrestrial species, which could be considered an adaptation to overcome buoyancy during swimming and shallow diving. Generally, it seems that different osteological properties at the levels of mineral density and biomechanics could be compatible with the adaptation to aquatic, semiaquatic, or terrestrial niches. [ABSTRACT FROM AUTHOR]

The Ganges river dolphin, also known as 'Susu', is a blind aquatic mammal endemic to the Indian subcontinent. Its population has declined significantly over the past 40 years due to threats such as deliberate killing, pollution, and habitat fragmentation. The Indian government has taken steps to conserve the species, including the establishment of the Vikramshila Gangetic Dolphin Wildlife Sanctuary and declaring the GRD as the National Aquatic Animal of India. Collaborative efforts have led to an increase in the dolphin population, but more work is needed. Proposed actions include collaboration among stakeholders, coordination with global experts, cooperation for transboundary commissions, augmentation of protected areas, implementation of e-flow regulations, integration of terrestrial and freshwater ecosystems, engagement of local communities, inclusion of educational activities, conduction of awareness programs, and adoption of advanced digital technologies. These actions aim to improve conservation efforts and elevate the livelihoods of local communities. [Extracted from the article]

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]

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]

The endangered Saimaa ringed seal (Pusa hispida saimensis) is an endemic freshwater subspecies inhabiting Lake Saimaa in Finland. The Baltic ringed seal (Pusa hispida botnica) inhabits the brackish Baltic Sea, which is almost entirely landlocked. Recent research shows that Saimaa and Baltic ringed seals may be genetically even further apart from each other than from other ringed seal subspecies. We documented histologically the integument microstructure of Saimaa and Baltic ringed seals to determine whether the geographic and genetic isolation was manifested as variation in the integument microstructure of these subspecies adapted to icy aquatic environments. The skin structures of these subspecies were similar to those of other phocids. The association of the sweat glands with hair follicles in both subspecies suggested that they were small apocrine sweat glands described previously in terrestrial or aquatic mammals. None of the apocrine glands had large lumina, and some of the ducts were relatively straight and short. Further studies analysing the mode of secretion, for example, apocrine versus eccrine, in the sweat glands are necessary to confirm the types of sweat glands in seals. [ABSTRACT FROM AUTHOR]

The Amazonian manatee (Trichechus inunguis) is an aquatic mammal threatened with extinction. However, few studies have investigated the pathogens in this species, which may affect both animal and human health. This study aimed to evaluate the frequency, distribution, and patterns of antimicrobial susceptibility of Staphylococcus spp. and Escherichia coli colonizing the nasal and rectal cavities of Amazonian manatees kept in captivity at the National Institute for Amazonian Research (INPA) in the state of Amazonas, Brazil. Rectal and nasal swabs from 44 manatees of different ages were used in this study. The genus Staphylococcus was isolated from the nasal swabs of 32 (72.7%) animals, with two individuals harboring more than one species of Staphylococcus. S. sciuri was the most commonly isolated species. Resistance to penicillin was observed in 13 (40.6%) isolates, more frequent than the other antimicrobials tested (P = 0.01). E. coli was isolated from the rectal swabs of all animals, with phylogroup B1 being the most frequent among the strains obtained (P = 0.0008). Four isolates (6.8%) were positive for virulence factors, three of which were classified as enterotoxigenic E. coli (ETEC) and one as enteropathogenic E. coli (EPEC). To our knowledge, this is the first study to evaluate Staphylococcus spp. and E. coli in Amazonian manatee samples. This study revealed nasal colonization by Staphylococcus spp., mainly S. sciuri, and diarrheagenic E. coli isolates, including antimicrobial-resistant strains. [ABSTRACT FROM AUTHOR]

Sirenians of the superorder Afrotheria were the first mammals to transition from land to water and are the only herbivorous marine mammals. Here, we generated a chromosome-level dugong (Dugong dugon) genome. A comparison of our assembly with other afrotherian genomes reveals possible molecular adaptations to aquatic life by sirenians, including a shift in daily activity patterns (circadian clock) and tolerance to a high-iodine plant diet mediated through changes in the iodide transporter NIS (SLC5A5) and its co-transporters. Functional in vitro assays confirm that sirenian amino acid substitutions alter the properties of the circadian clock protein PER2 and NIS. Sirenians show evidence of convergent regression of integumentary system (skin and its appendages) genes with cetaceans. Our analysis also uncovers gene losses that may be maladaptive in a modern environment, including a candidate gene (KCNK18) for sirenian cold stress syndrome likely lost during their evolutionary shift in daily activity patterns. Genomes from nine Australian locations and the functionally extinct Okinawan population confirm and date a genetic break ~10.7 thousand years ago on the Australian east coast and provide evidence of an associated ecotype, and highlight the need for whole-genome resequencing data from dugong populations worldwide for conservation and genetic management. Sirenians are aquatic mammals that originated in Africa ~60 million years ago. Using comparative genomics of a new dugong genome, this study finds genetic adaptations shared by extant sirenians and assessed the diversity of dugongs in Australian waters and the functionally extinct Okinawan dugong. [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]

This article discusses a study that compares the whistles emitted by common bottlenose dolphins in three different regions: Revillagigedo Archipelago in Mexico, Saint Peter and Saint Paul Archipelago in Brazil, and the western Coast of Aragua in Venezuela. The study aims to understand the geographic variation in dolphin whistles in these regions. The study collected acoustic recordings from each location and analyzed the data to provide an overview of whistle variation among the studied areas. The results show that there are differences in whistle characteristics between the locations, suggesting that environmental adaptations, social factors, and genetic divergence may influence dolphin communication. Further research is needed to explore these factors in more detail. [Extracted from the article]

Cetaceans and pinnipeds are lineages of mammals that have independently returned to the aquatic environment, acquiring varying degrees of dependence on it while sharing adaptations for underwater living. Here, we focused on one critical adaptation from both groups, their ability to withstand the ischemia and reperfusion experienced during apnea diving, which can lead to the production of reactive oxygen species (ROS) and subsequent oxidative damage. Previous studies have shown that cetaceans and pinnipeds possess efficient antioxidant enzymes that protect against ROS. In this study, we investigated the molecular evolution of key antioxidant enzyme genes (CAT, GPX3, GSR, PRDX1, PRDX3, and SOD1) and the ROS-producing gene XDH, in cetaceans and pinnipeds lineages. We used the ratio of non-synonymous (dN) to synonymous (dS) substitutions as a measure to identify signatures of adaptive molecular evolution in these genes within and between the two lineages. Additionally, we performed protein modeling and variant impact analyzes to assess the functional consequences of observed mutations. Our findings revealed distinct selective regimes between aquatic and terrestrial mammals in five of the examined genes, including divergences within cetacean and pinniped lineages, between ancestral and recent lineages and between crowns groups. We identified specific sites under positive selection unique to Cetacea and Pinnipedia, with one site showing evidence of convergent evolution in species known for their long and deep-diving capacities. Notably, many sites under adaptive selection exhibited radical changes in amino acid properties, with some being damaging mutations in human variations, but with no apparent detrimental impacts on aquatic mammals. In conclusion, our study provides insights into the adaptive changes that have occurred in the antioxidant systems of aquatic mammals throughout their evolutionary history. We observed both distinctive features within each group of Cetacea and Pinnipedia and instances of convergence. These findings highlight the dynamic nature of the antioxidant system in response to challenges of the aquatic environment and provide a foundation for further investigations into the molecular mechanisms underlying these adaptations. [ABSTRACT FROM AUTHOR]

The article discusses the negative impacts of cetacean tourism, such as whale watching, on cetacean populations. It suggests that current management strategies are ineffective due to a lack of regulation, low compliance with guidelines, and a lack of enforcement. The article proposes incorporating concepts from successful business management to improve cetacean tourism management and achieve sustainability. It emphasizes the importance of considering the perspectives and safety of tourists in addition to the well-being of cetaceans. The provided text consists of a list of academic articles and studies related to the impact of tourism on marine mammals, specifically dolphins and whales. The articles cover various topics such as the effects of tourism on behavior, compliance with guidelines, and the sustainability of tourist interactions with cetaceans. The studies examine the behavioral responses of dolphins to vessel presence, the long-term effects of swim-with-dolphin tourism, and the implications of whale-watching activities on conservation. The articles provide valuable insights into the complex relationship between tourism and marine mammals, highlighting the need for responsible and sustainable practices in the industry. The given list of sources includes research articles on the topic of whale watching and its impacts. The articles cover topics such as the negative impacts of whale watching, recent advances in research, compliance with regulations, and the behavior of dolphins and whales in the presence of whale watching vessels. The research examines the effects of whale watching on cetaceans, such as changes in behavior and increased stress levels. It also explores the effectiveness of regulations and codes of conduct in [Extracted from the article]

This article provides an update on the cetacean species list in Raja Ampat, Indonesia, with new sightings of Omura's whale and melon-headed whales. The study was conducted through boat-based surveys and opportunistic observations using drones and ferries. The researchers encountered five species, including Omura's whales and melon-headed whales. These findings contribute to filling information gaps and updating the cetacean species list in Raja Ampat. The document also provides a list of references related to marine biodiversity, marine mammals, and conservation efforts in Indonesia, which can be valuable resources for library patrons conducting research on these subjects. [Extracted from the article]

The article discusses the development of a Holistic Pinniped Welfare Index (HPWI) as a tool to assess the welfare of pinnipeds in managed care. The HPWI incorporates both animal-based and resource-based approaches to welfare assessment, taking into account factors such as hunger and thirst, appropriate housing, absence of illness or injury, and appropriate behaviors and interactions. The index is specifically tailored to address the unique needs and behaviors of furred pinnipeds. The article highlights the importance of considering factors such as fur condition and skin health in assessing pinniped welfare. The text also discusses the use of the Pinniped Welfare Index (HPWI) as a tool for assessing the health and well-being of pinnipeds in managed care facilities. The HPWI includes both physiological and behavioral measures, such as body condition, skin lesions, respiratory effort, and willingness to perform trained behaviors. The index can be used to compare data over time and identify abnormalities that may indicate disease or stress. The text emphasizes the importance of developing specific ethograms for each facility to accurately assess behavioral patterns. The list of references includes various scientific articles related to animal welfare, specifically focusing on topics such as the assessment of welfare in captive dolphins, the use of behavioral indicators to evaluate welfare, and the monitoring of body temperature as a stress response in marine mammals. The articles cover a range of species, including bottlenose dolphins, sea lions, and pinnipeds, and discuss different methods and indicators used [Extracted from the article]

Simple Summary: Japanese encephalitis virus (JEV) infections in seals are limited, with only two cases reported. Here, we report a case of meningoencephalitis and bronchopneumonia caused by the co-infection of JEV and Schizophyllum commune in a dead seal (Phoca vitulina) housed in an aquarium in Japan. The JEV isolate from the seal was classified as genotype GIb based on E gene sequences, which included recent Japanese human and mosquito isolates. The Japanese encephalitis virus (JEV), a mosquito-borne flavivirus, has a wide host range, extending from pigs and ardeid birds to opportunistic dead-end hosts, such as humans and horses. However, JEV encephalitis infections in aquatic mammals are rare, with only two cases in seals reported to date. Here, we report a lethal case of JEV and Schizophyllum commune co-infection in an aquarium-housed harbor seal in Japan. We isolated JEV from the brain of the dead seal and characterized its phylogeny and pathogenicity in mice. The virus isolate from the seal was classified as genotype GIb, which aligns with recent Japanese human and mosquito isolates as well as other seal viruses detected in China and Korea, and does not exhibit a unique sequence trait distinct from that of human and mosquito strains. We demonstrated that the seal isolate is pathogenic to mice and causes neuronal symptoms. These data suggest that seals should be considered a susceptible dead-end host for circulating JEV in natural settings. [ABSTRACT FROM AUTHOR]

The mammalian epidermis has evolved to protect the body in a dry environment. Genes of the epidermal differentiation complex (EDC), such as FLG (filaggrin), are implicated in the barrier function of the epidermis. Here, we investigated the molecular evolution of the EDC in sirenians (manatees and dugong), which have adapted to fully aquatic life, in comparison to the EDC of terrestrial mammals and aquatic mammals of the clade Cetacea (whales and dolphins). We show that the main subtypes of EDC genes are conserved or even duplicated, like late cornified envelope (LCE) genes of the dugong, whereas specific EDC genes have undergone inactivating mutations in sirenians. FLG contains premature stop codons in the dugong, and the ortholog of human CASP14 (caspase-14), which proteolytically processes filaggrin, is pseudogenized in the same species. As FLG and CASP14 have also been lost in whales, these mutations represent convergent evolution of skin barrier genes in different lineages of aquatic mammals. In contrast to the dugong, the manatee has retained functional FLG and CASP14 genes. FLG2 (filaggrin 2) is truncated in both species of sirenians investigated. We conclude that the land-to-water transition of sirenians was associated with modifications of the epidermal barrier at the molecular level. [ABSTRACT FROM AUTHOR]

For many aquatic and semiaquatic mammal, amphibian and fish species, environmental DNA (eDNA) methods are employed to detect species distribution and to monitor their presence, but eDNA is much less employed for avian species. Here, we developed primers for the detection of true geese and swan species using eDNA and optimised a PCR protocol for eDNA. We selected taiga bean goose (Anser fabalis fabalis) as our focal (sub)species and sampled water from lakes, from which the presence of taiga bean goose was visually confirmed. To test, if taiga bean goose DNA could be detected among DNA of other goose species, we similarly sampled eDNA from a zoo pond housing several Anatidae species. We were able to detect taiga bean goose DNA in all but one of the tested lakes, including the zoo pond. The primers developed are not species‐specific, but rather specific to the genus Anser, due to the close relatedness of Anser species, which prevented the development of species‐specific primers and the use of, for example, quantitative PCR. We also developed eDNA primers for Branta species and Cygnus species and tested these primers using the same samples. Canada goose (B. canadensis) and barnacle goose (B. leucopsis) DNA were only detected in the zoo pond (in which they were present), as the sampled natural lakes fall outside the range of these species. We detected whooper swan (C. cygnus) DNA in three lakes and the zoo pond (in which the species was present). The eDNA method presented here provides a potential means to monitor elusive goose species and to study the co‐occurrence of large waterfowl. [ABSTRACT FROM AUTHOR]

Introduction: Use of mechanical ventilation during general anesthesia is a necessary practice in the anesthetization of small cetaceans as spontaneous ventilation fails to provide adequate gas exchange. Currently available methods of ventilation do not account for the intermittent breathing strategy of representative species within this infraorder of fully aquatic mammals and may have a significant effect on cardiac and respiratory physiology. Methods: To understand the impact of mechanical ventilation on cardiopulmonary function in one small species of cetacean, the bottlenose dolphin (Tursiops truncatus), we compared controlled mechanical ventilation (CMV) to a novel ventilation method known as apneustic anesthesia ventilation (AAV). AAV simulates the normal inspiratory breath-hold pattern of dolphins. Ten anesthetic procedures (dental procedure, n = 9; bronchoscopy, n = 2) were performed on nine dolphins (age range: 10-42 years; mean = 32 years; median = 37 years; female = 3, 40%; male = 6, 60%). In a cross-over study design, dolphins were instrumented and randomly assigned to AAV or CMV as the initial mode of ventilation, then switched to the alternate mode. Baseline cardiopulmonary data were collected and again after 30 min on each mode of ventilation. Cardiac index, stroke volume index, systemic vascular resistance, alveolar dead space, alveolar-arterial oxygen tension gradient, arterial oxygen content, oxygen delivery index, and dynamic respiratory system compliance index were calculated at each of the four time points. Results: During AAV, dolphins had higher arterial oxygen tension, higher mean airway pressure, reduced alveolar dead space ventilation and lower alveolararterial oxygen difference. Cardiovascular performance was not statistically different between the two modes. Discussion: Our study suggests AAV, which more closely resembles the conscious intermittent respiratory pattern phenotype of dolphins, improves ventilation and pulmonary function in the anesthetized dolphin. Future studies should evaluate the cardiopulmonary effects of neutral buoyancy and cardiopulmonary sparing drug protocols to reduce the need for hemodynamic support of current protocols. [ABSTRACT FROM AUTHOR]

This article presents a study on estimating tidal lung volumes (VT) in adult gray whales using audio and video recordings. The researchers used unmanned aerial systems (UAS) to monitor foraging whales in coastal waters and compared their findings to previous studies conducted in a winter breeding/calving lagoon. The results indicate that tidal lung volume can be estimated based on body length and exhalation duration. This method provides a new tool for understanding the metabolic rate and resource requirements of gray whales, as well as the impact of changing oceanographic conditions on their prey availability. [Extracted from the article]

The article discusses a study on the seasonal occurrence of harbor seals near Oregon Inlet, North Carolina, USA, conducted by Britney E. Pepper et al., published in the journal. It highlights the recolonization of areas by harbor seals, expansion of their seasonal range southward, and potential impacts of human activities like bridge construction and demolition on their habitat and conservation.

The article discusses a study on evidence of a predatory interaction between a cookiecutter shark (Isistius brasiliensis) and Galapagos fur seals (Arctocephalus galapagoensis) conducted by Andrés Moreira-Mendieta et al., published in the journal Aquatic Mammals. It highlights the occurrence of a fresh circular wound on a fur seal caused by a cookiecutter shark, emphasizing the potential impact of such sublethal predation events on the fitness of the prey species.

The article discusses a study on the evidence for an oceanic population of killer whales (Orcinus orca) in offshore waters of California and Oregon conducted by Josh D. McInnes et al., published in the journal ". The study attempts to determine the ecotype of killer whales observed far from the coastlines based on their foraging behaviors, prey species consumed, morphologies, and the prevalence of cookiecutter shark bite scars.

The article discusses the first recorded live-stranding of an Antarctic Minke Whale (AMW) in the Caribbean Sea, providing details on the identification process and morphological characteristics.Topics include the migration patterns of AMWs, diagnostic characteristics for identification, and potential causes for their presence in non-native regions.

Simple Summary: The welfare committee of the European Association for Aquatic Mammals (EAAM) set up a group of experts on welfare science, cetacean biology, and zoo animal medicine across Europe to develop a comprehensive tool to evaluate the welfare of bottlenose dolphins (Tursiops truncatus) under human care named Dolphin-WET. The tool encompasses 49 indicators (i.e., 37 animal-based and 12 resource-based indicators) inspired by Mellor's Five Domains Model and the Welfare Quality®. The Dolphin-WET is a species-specific and individual-based welfare assessment tool that provides a holistic approach to evaluating bottlenose dolphins' welfare. Ensuring high standards of animal welfare is not only an ethical duty for zoos and aquariums, but it is also essential to achieve their conservation, education, and research goals. While for some species, animal welfare assessment frameworks are already in place, little has been done for marine animals under human care. Responding to this demand, the welfare committee of the European Association for Aquatic Mammals (EAAM) set up a group of experts on welfare science, cetacean biology, and zoo animal medicine across Europe. Their objective was to develop a comprehensive tool to evaluate the welfare of bottlenose dolphins (Tursiops truncatus), named Dolphin-WET. The tool encompasses 49 indicators that were either validated through peer review or management-based expertise. The first of its kind, the Dolphin-WET is a species-specific welfare assessment tool that provides a holistic approach to evaluating dolphin welfare. Inspired by Mellor's Five Domains Model and the Welfare Quality®, its hierarchical structure allows for detailed assessments from overall welfare down to specific indicators. Through combining 37 animal-based and 12 resource-based indicators that are evaluated based on a two- or three-level scoring, the protocol offers a detailed evaluation of individual dolphins. This approach allows for regular internal monitoring and targeted welfare management, enabling caretakers to address specific welfare concerns effectively. [ABSTRACT FROM AUTHOR]

Simple Summary: The conservation of endangered wild species such as the Amazon manatee (Trichechus inunguis) requires important attention, as the species plays a crucial role in the maintenance and stability of the Amazon ecosystem. Among several areas of scientific research that help in the conservation of species, cryopreservation is a technique that guarantees storing cells at extremely low temperatures for long-term preservation. In this work, we established the first Amazonian manatee cell line (TINsf) from a skin biopsy. We observe its shape and growth rate over time. Furthermore, we also evaluated how Amazonian manatee cells reacted to andiroba seed oil (ASO) and found that low concentrations of ASO do not affect the growth of TINsf cells, but high concentrations cause a reduction in cell proliferation and cell death. Here, we promisingly show that, in addition to establishing Amazonian manatee cell lines, it was possible to guarantee their applicability for future research. The vulnerable status of the Amazon manatee, Trichechus inunguis, indicates the need to seek measures to guarantee its conservation. In this context, the cultivation of cells in vitro is a strategy that should at least guarantee the preservation of their genetic material. Thus, we established for the first time a primary culture of Amazonian manatee fibroblasts (TINsf) from a skin biopsy of a young male. Karyotypic analysis of the 3rd, 7th, and 12th passages confirmed the taxonomic identity of the species T. inunguis (2n = 56/NF = 92) and indicated that this culture presents genomic stability. Gene and protein expression of vimentin at the 13th passage show the predominant presence of fibroblasts in TINsf. To test the cell line's responsiveness to materials and demonstrate a possible application of this culture, it was exposed to andiroba seed oil (ASO), and its viability and proliferative capacity were evaluated. ASO demonstrated toxic effects at the highest concentrations and longest exposure times tested, reproducing results observed in human cultures, indicating the applicability of TINsf in toxicological and biotechnological studies. After cryopreservation, the TINsf line maintained its proliferative potential, indicating the establishment of a new culture available for future studies. [ABSTRACT FROM AUTHOR]

The rate of hydropower dam construction on rivers is increasing in emerging economies in South Asia, to achieve economic development goals. These large infrastructure projects are likely to have many negative consequences on freshwater species but have not yet received much consideration. Among freshwater small mammalian species, water shrews are seriously impacted by these large structures. This paper aims to determine if water shrews have been considered during the Environmental Impact Assessment (EIA) of these hydro dam project sites, as well as present the sightings of the water shrews from Nepalese rivers with hydropower potential. We reviewed 44 EIA reports of such projects in Nepal using a set of four criteria and 15 questions to analyze the methods of impact assessment for mammals and the reports on the presence of water shrews in each built area. The study found that the number of mammal species reported during the EIA varied from five to 55 species but no relationships between the hydropower structure's size and any water shrew species were considered in the studies. In almost all EIA reports, the term aquatic ecosystem was prioritized over the term aquatic small mammals, and the latter was not considered in the assessment. The major reason for not considering these species is probably due to the lack of robust methods to capture small mammals such as shrews, or due to survey methods focused only on terrestrial mammals. The Aquatic Animal Protection Act was fully reviewed and assured to be followed in a majority of the reports, yet the monitoring parameters and indicators were not available for aquatic small mammals. Ignoring the presence of these mammals while constructing hydropower plants is a serious threat to their persistence. We also reported the Himalayan water shrew in the Barun River and the elegant water shrew in the Upper Tamakoshi River of Nepal. Therefore, a better understanding of these species among hydropower developers, and all concerned agencies, is essential. [ABSTRACT FROM AUTHOR]

The Alliance of Marine Mammal Parks and Aquariums (AMMPA) held its 2024 Annual Meeting in San Diego, California, marking the first time the association has met on the West Coast. The meeting featured speakers discussing topics such as marine animal research, conservation, and animal welfare. Presentations included talks on conserving marine mammals in changing oceans, the work of the Hubbs-SeaWorld Research Institute, and the Marine Mammal Research Network. The meeting also addressed animal welfare practices in zoological facilities and included discussions on mental health needs of zoo and aquarium employees. [Extracted from the article]

Chemoreception – the ability to smell and taste – is an essential sensory modality of most animals. The number and type of chemical stimuli that animals can perceive depends primarily on the diversity of chemoreceptors they possess and express. In vertebrates, six families of G protein-coupled receptors form the core of their chemosensory system, the olfactory/pheromone receptor gene families OR, TAAR, V1R and V2R, and the taste receptors T1R and T2R. Here, we study the vertebrate chemoreceptor gene repertoire and its evolutionary history. Through the examination of 1,527 vertebrate genomes, we uncover substantial differences in the number and composition of chemoreceptors across vertebrates. We show that the chemoreceptor gene families are co-evolving, highly dynamic, and characterized by lineage-specific expansions (for example, OR in tetrapods; TAAR, T1R in teleosts; V1R in mammals; V2R, T2R in amphibians) and losses. Overall, amphibians, followed by mammals, are the vertebrate clades with the largest chemoreceptor repertoires. While marine tetrapods feature a convergent reduction of chemoreceptor numbers, the number of OR genes correlates with habitat in mammals and birds and with migratory behavior in birds, and the taste receptor repertoire correlates with diet in mammals and with aquatic environment in fish. Chemoreception - the ability to smell and taste - relies on diverse receptor genes. Examining 1,527 vertebrate genomes, this study explores the dynamic evolution, lineage-specific expansions and losses of chemoreceptor genes as well as ecological and morphological factors associated with these. [ABSTRACT FROM AUTHOR]

Some taxa of mammals live in water, all of which evolved from land-dwelling ancestors. In the family Mustelidae (Mammalia: Carnivora), most species live on land, while otters, comprising the subfamily Lutrinae, inhabit aquatic environments, which include the almost exclusively aquatic sea otters (Enhydra lutris). Thus, the transition from a terrestrial to an aquatic lifestyle has occurred within this family. Despite potentially different selection pressures on body size in aquatic and terrestrial habitats, no divergence in the evolutionary pattern of body size between otters and other mustelids has previously been shown using models of trait evolution on a phylogeny. We applied models that explicitly incorporated lineage-specific directional selection to the evolution of body mass in living mustelids. Using a simulation-based likelihood and approximate Bayesian computation approach, we demonstrated lineage-specific directional selection for larger body mass in otters, which is distinct from other mustelids. There was no evidence of a difference between sea otters and other otters in the strength of directional selection for larger body mass. Additionally, our analyses supported no difference in the rate at which body mass evolves in both directions between otters and other mustelids. These findings suggest that the evolution of body mass in otters is associated with selective advantages of larger size rather than the relaxation of constraints on body size in aquatic habitats, like other aquatic mammals such as sirenians, cetaceans, and pinnipeds. [ABSTRACT FROM AUTHOR]

The Indus River dolphin (Platanista minor) is a severely threatened species of freshwater dolphin that occurs only in the lower Indus River system of Pakistan and India. The dolphin's range has declined by 80% since the 1870s, and total species abundance is estimated as approximately 2000 individuals.In 2007, a remnant population of Indus dolphins was discovered above Harike Barrage, in the Beas River in India, 600 km away from all other individuals of its species. This paper provides an overview of the conservation status of Indus dolphins in the Beas River, details the threats they face, and suggests priorities for their conservation and management.Between 2011 and 2022, 40 dolphin direct count surveys were conducted. Indus dolphins occur only in the lower third of the Beas River and reported counts have been from one to eight individuals. The data do not indicate an increase in abundance, and instead suggest a potential decrease; however, sightings of calves continue to be reported annually indicating reproduction is still taking place.Threats to the Beas River dolphin population include accidental entanglement in fishing gear, pollution, escapement downstream of Harike barrage, altered and depleted river flow regimes' and the effects of a very small population size. Urgent conservation measures are essential if this small, but important satellite population is to persist.Recommended management actions include the complete removal of fishing nets from dolphin habitat, reducing pollution, ensuring adequate river discharge to sustain aquatic ecology including dolphins, evaluating and monitoring dolphin movement through Harike barrage and into canals, and engaging riverside communities to protect dolphins. In addition, the possibility of conservation translocations to supplement this population with individuals from larger healthy populations elsewhere in the range of the species should be explored. [ABSTRACT FROM AUTHOR]

Long‐term systematic records of cetacean strandings are valuable indicators of temporal responses of specific cetacean populations and communities to natural or anthropogenic pressures. They also help guide management objectives and conservation actions.Generalized additive models (GAMs) were used to analyse 10 years of systematic and opportunistic surveys of Guiana dolphin strandings in the Amazon Estuary region, Northern Brazil. The spatial distribution of strandings was assessed through kernel density maps, and age‐at‐death structure of this population was described.The model results revealed marked seasonality in the strandings and, by extension, the mortality of Guiana dolphins in the Amazon Estuary. This seasonality varied between the inner estuarine regions and Atlantic coastal area, reflecting the environment's characteristics. Long‐term decline of strandings in the Amazon Estuary inner region and unusual high mortality of young sexually mature individuals were detected. These results, besides the high stranding rate detected for the species, are mostly attributed to the species' interaction with intense fishing activity in the region.Conservation efforts should consider the seasonality of Guiana dolphin strandings in the Amazon Estuary. The systematic monitoring of strandings, especially in high‐frequency areas, is recommended for assessing long‐term species mortality. Additionally, implementing management actions related to the species' interaction with fishing activities, such as regulatory enhancements, gillnet modifications and seasonal no‐fishing zones, is advised. Educational campaigns targeting fishermen and riverine communities are essential to reduce bycatch and the folkloric use of the species.This study underscores the effectiveness of stranding data as a source of biological and ecological information, and as a tool for understanding human actions affecting coastal populations of aquatic mammals. It emphasizes the need for urgent studies to characterize this population, clarify the influence of bycatch as an anthropogenic pressure and implement effective conservation actions to preserve the Guiana dolphin population. [ABSTRACT FROM AUTHOR]

During evolution, animals have returned from land to water, adapting with morphological modifications to life in an aquatic environment. We compared the osteochondral units of the humeral head of marine and terrestrial mammals across species spanning a wide range of body weights, focusing on microstructural organization and biomechanical performance. Aquatic mammals feature cartilage with essentially random collagen fiber configuration, lacking the depth-dependent, arcade-like organization characteristic of terrestrial mammalian species. They have a less stiff articular cartilage at equilibrium with a significantly lower peak modulus, and at the osteochondral interface do not have a calcified cartilage layer, displaying only a thin, highly porous subchondral bone plate. This totally different constitution of the osteochondral unit in aquatic mammals reflects that accommodation of loading is the primordial function of the osteochondral unit. Recognizing the crucial importance of the microarchitecture-function relationship is pivotal for understanding articular biology and, hence, for the development of durable functional regenerative approaches for treatment of joint damage, which are thus far lacking. [ABSTRACT FROM AUTHOR]

The article informs about the identification of the ecotype origin of an entangled killer whale using remnant mtDNA after being found dead and ensnared in recreational Dungeness crab gear off the coast of Newport, Oregon. Topic include the study uses investigative molecular methods to determine the killer whale's ecotype, highlighting the significance of genetic markers in identifying sympatric groups within killer whale populations in the Northeast Pacific.

The article discusses about a typical coloration in marine mammals, particularly piebaldism in common bottlenose dolphins. Topic include It highlights the rarity of such occurrences, emphasizes the ecological implications, and presents the first documented case of a piebald dolphin in Australian waters during cetacean surveys in Hervey Bay, Queensland.

The article informs about the first records of pinnipeds (Otariidae) along the Pacific Coast of Nicaragua, addressing topics such as the influence of oceanographic conditions, prey availability, and human activities on pinniped movements. Topic include the authors highlight the scarcity of knowledge regarding pinniped presence in Central America and emphasize the importance of documenting sightings for ecological understanding, and assessing reasons for their presence in atypical areas.

With the widespread use of organophosphate esters (OPEs), the accumulation and toxicity effect of OPEs in biota are attracting more and more concern. In order to clarify the mechanism of toxicity of OPEs to organisms, this study reviewed the OPEs toxicity and systematically identified the mechanism of OPEs toxicity under the framework of adverse outcome pathway (AOP). OPEs were divided into three groups (alkyl-OPEs, aryl-OPEs, and halogenated-OPEs) and biota was divided into aquatic organism and mammals. The results showed that tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) and triphenyl phosphate (TPHP) mainly caused neurotoxicity, reproductive, and hepatotoxicity in different mechanisms. According to the constructed AOP network, the toxicity mechanism of OPEs on aquatic organisms and mammals is different, which is mainly attributed to the different biological metabolic systems of aquatic organisms and mammals. Interestingly, our results indicate that the toxicity effect of the three kinds of OPEs on aquatic organisms is different, while there was no obvious difference in the mechanism of toxicity of OPEs on mammals. This study provides a theoretical basis for OPEs risk assessment in the future. [ABSTRACT FROM AUTHOR]

The Mediterranean monk seal (Monachus monachus, Hermann, 1779) is an endangered species of pinniped endemic to few areas of the Mediterranean Sea. Extensive hunting and poaching over the last two centuries have rendered it a rare sight, scattered mainly in the Aegean Sea and the western coast of North Africa. In a rare event, a female monk seal calf stranded and died in southern Italy (Brindisi, Puglia). During due necropsy, the brain was extracted and fixed. The present report is the first of a monk seal brain. The features reported are remarkably typical of a true seal brain, with some specific characteristics. The brain cortical circonvolutions, main fissures and the external parts are described, and an EQ was calculated. Overall, this carnivore adapted to aquatic life shares some aspects of its neuroanatomy and physiology with other seemingly distant aquatic mammals. [ABSTRACT FROM AUTHOR]

In Venezuela, Antillean manatees (Trichechus manatus manatus) have declined mainly due to habitat loss and degradation, but other threats to the species persist. The objective of this work was to investigate the manatee distribution and conservation issues in Maracaibo Lake, Venezuela. Aiming to collect evidence on manatee presence, we conducted 404.14 hours of boat-based surveys and observations from the shore during 2003, 2004, 2009, and 2010. Environmental parameters were collected in areas where manatees were observed including pH, temperature, dissolved oxygen, salinity, transparency, and depth. Also, we recorded plants or algae that could serve as potential food for manatees. We developed 96 informal and opportunistic talks with local fishermen, to gather information about manatee occurrence, boat traffic, and people’s perception of the species. Finally, we reviewed published and unpublished documents containing information on manatees in Maracaibo Lake. The resulting database contains information on 39 sightings and 13 reports of dead manatees. The known causes of death were poaching, vandalism, boat collision, and entanglement in fishing nets. The Maracaibo Lake offers many suitable habitats for manatees, but also faces a wide array of conservation problems that represent critical threats to this endangered subspecies. Long-term monitoring of this population and potential sources of mortality is highly needed. [ABSTRACT FROM AUTHOR]

This article discusses the use of acoustic tags and bottom-moored recorders to study the impulsive sounds produced by humpback whales during surface active behavior. The study combines data from passive acoustic monitoring (PAM) and instrumented suction cup tags to gain insights into humpback whale behavior and communication. The impulsive sounds were found to be associated with surface-active behaviors such as tail slaps and pectoral fin slaps. The presence of these impulsive sounds in PAM data can provide valuable information about the occurrence and activity of humpback whales in a monitored area. [Extracted from the article]

This article presents a study on skull and mandible alterations in Amazon river dolphins, specifically focusing on the genus Inia spp. The researchers examined 105 specimens and identified various morphological, traumatic, and pathological alterations. The most common alterations observed were the presence of a third condyle and rostrum deviation. Interestingly, the study found no significant differences in the occurrence of these alterations based on sex, sexual maturity, or habitat. The study also identified cases of prognathism, brachygnathism, fractures, and pathological changes such as osteomyelitis and osteoarthritis. The researchers suggest that further research is needed to understand the causes and implications of these skull alterations. [Extracted from the article]

We measured resting metabolic rate (RMR), tidal volume (VT), breathing frequency (fR), respiratory flow, and end‐expired gases in rough‐toothed dolphins (Steno bredanensis) housed in managed care after an overnight fast and 1–2 hr following a meal. The measured average (± standard deviation) VT (4.0 ± 1.3 L) and fR (1.9 ± 1.0 breaths/min) were higher and lower, respectively, as compared with estimated values from both terrestrial and aquatic mammals, and the average VT was 43% of the estimated total lung capacity. The end‐expired gas levels suggested that this species keep alveolar O2 (10.6% or 80 mmHg) and CO2 (7.6% or 57 mmHg), and likely arterial gas tensions, low and high, respectively, to maximize efficiency of gas exchange. We show that following an overnight fast, the RMR (566 ± 158 ml O2/min) was 1.8 times the estimated value predicted by Kleiber for terrestrial mammals of the same size. We also show that between 1 and 2 hr after ingestion of a meal, the metabolic rate increases an average of 29% (709 ± 126 ml O2/min). Both body mass (Mb) and fR significantly altered the measured RMR and we propose that both these variables should be measured when estimating energy use in cetaceans. [ABSTRACT FROM AUTHOR]

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In the context of macroevolutionary transitions, environmental changes prompted vertebrates already bearing genetic variations to undergo gradual adaptations resulting in profound anatomical, physiological, and behavioral adaptations. The emergence of new genes led to the genetic variation essential in metazoan evolution, just as was gene loss, both sources of genetic variation resulting in adaptive phenotypic diversity. In this context, F12‐coding protein with defense and hemostatic roles emerged some 425 Mya, and it might have contributed in aquatic vertebrates to the transition from water‐to‐land. Conversely, the F12 loss in marine, air‐breathing mammals like cetaceans has been associated with phenotypic adaptations in some terrestrial mammals in their transition to aquatic lifestyle. More recently, the advent of technological innovations in western lifestyle with blood‐contacting devices and harmful environmental nanoparticles, has unfolded new roles of FXII. Environment operates as either a positive or a relaxed selective pressure on genes, and consequently genes are selected or lost. FXII, an old dog facing environmental novelties can learn new tricks and teach us new therapeutic avenues. [ABSTRACT FROM AUTHOR]