Search Results (74)

Climate change is altering the marine environment in many ways, including increasing sea surface temperatures and decreasing sea ice. Species distributions are changing and ‘out of habitat’ marine mammals are being recorded. ‘Out of habitat’ (OOH) refers to individuals recorded outside of their natural range or within environments unsuitable for their survival. This phenomenon is currently understudied. This study aimed to identify the scale of the issue, identify consensus opinions on trends and possible causes of these OOH events, as well as assessing the preparedness of local authorities and rescue networks in responding to OOH marine mammals. This study is the first to assess and quantify this issue through a formal consultation process, conducted through an online questionnaire and a detailed examination of two case studies, from the UK and Peru. Sixty-three questionnaire responses were received from six different continents and the majority (60%) reported OOH events in their region. Through the questionnaire and case studies, 42 different marine mammal species were reported to be affected. This clearly indicates this is a global phenomenon, affecting at least 32% of all known pinniped and cetacean species. Most participants (77%) also believed these OOH events are increasing, and 55% believe these events are forerunners to distribution changes. Data from Peru showed an endangered species, the Galápagos fur seal (Arctocephalus galapagoensis), had made a range shift. Of the reported OOH species, four are classified as either endangered or critically endangered. The consensus opinion was that climate change is the leading driver of these OOH events, with sea surface temperatures and changes in prey distribution reported as the most important factors. The success of OOH responses was reported as highly inconsistent and, in many cases, requires specialist training, e.g., in human–wildlife conflict. The information derived from this study can be used to advise conservation plans, as well as provide a foundational step for future research into the possible trends in these OOH movements. Full article

Candida albicans is currently considered one of the most significant fungal pathogens in cetaceans and pinnipeds and the spread of antifungal-resistant strains pose significant threats to animal health and One Health concerns. Although C. albicans is the most commonly detected species, non-albicans Candida (NAC) species, including C. tropicalis, C. parapsilosis and Nakaseomyces glabratus and the multidrug-resistant C. auris, have been recognized in captive dolphins. This review examines the clinical patterns observed in marine mammal taxa: cetaceans are most commonly vulnerable to respiratory and disseminated mycoses owing to their distinct anatomical characteristics, whereas mucocutaneous infections are the common manifestation in pinnipeds. Localized mucocutaneous infections may progress to fatal systemic disease, with mortality rates approaching 100% in severe cases, despite therapeutic treatment. The most important predisposing factors are immunosuppression, long-term antibiotic treatment, environmental stress factors, and the deterioration of water quality. Diagnostic methods are based on cytology, histopathology, culture, and molecular methods, and treatment is mostly composed of systemic azole antifungals although with high levels of therapeutic failure. Recent results showed that there are high levels of azole resistance in the isolates of marine mammals that had no history of exposure to antifungal agents, which points to the role of aquatic environments as sources of resistance genes. The lack of knowledge remains particularly evident in species-specific pharmacokinetics and the development of evidence-based treatment guidelines. These infections also have broader implications for ecosystem health surveillance and the protection of endangered marine mammal populations. The current review highlights the One Health approach with marine mammals being at the core of ocean health surveillance and identifies the potential for zoonotic transmission. Full article

The spotted seal (Phoca largha) is an ice-associated pinniped in the Northwest Pacific and is a subject of conservation concern under increasing environmental and anthropogenic pressures; however, genomic studies have been constrained by the absence of a high-quality reference genome. Here, we present a near-telomere-to-telomere (near-T2T), gap-free genome assembly of P. largha spanning 2.39 Gb and comprising 16 chromosome-length sequences, with a scaffold N50 of 184.39 Mb and high completeness (99.34% complete BUSCOs). Compared with the previous chromosome-level assembly, the new genome improves contiguity and gene-space completeness. Comparative analyses across 20 carnivoran species resolve P. largha as sister to Phoca vitulina with an estimated divergence time of ~2.1 Ma. Branch-site positive-selection analyses and gene-family evolution analyses identify lineage-associated changes, and enrichment results motivate focused investigation of integument-related gene families. Targeted analyses of keratin (KRT) and matrix metalloproteinase (MMP) families reveal contrasting chromosomal organisation and evolutionary dynamics: KRTs form large chromosomal clusters with broadly conserved synteny across Carnivora but lineage-dependent remodelling within clusters, whereas MMPs are dispersed and display largely conserved orthologous correspondence. This high-quality genome provides a high-quality resource for pinniped comparative genomics and for elucidating the genomic architecture of skin and fur adaptation. Full article

Orthohalarachne attenuata and O. diminuata mites are parasites of the respiratory system of Pinnipeds. During hosts’ dives, mites must cope with changing conditions of oxygen availability in the nasal cavity. Adults and nymphs live inside the host, but larvae are active and responsible for colonizing new hosts. Hence, larvae are also exposed to environmental conditions with variable temperature and pressure, as well as to dehydration and changes in salinity. Although both species live within the respiratory tract of hosts, adults attach to different sections. Also, larvae have differential thermal tolerances and locomotion capacities. In this study, we show the effect of hypoxia, humidity and salinity on survival of O. attenuata and O. diminuata mite larvae. We found that both species are highly tolerant to hypoxia and can withstand it for long periods. In turn, both species showed low survival when exposed to direct air. Finally, hyperosmotic solution was highly harmful for O. attenuata, but not for O. diminuata. Our results show that humidity rather than oxygen availability is a constraint for survival and a limitation for dispersal when searching for new hosts. The present study expands our knowledge of ecophysiology and adaptations to changing conditions experienced during the dispersal of these marine parasite species. Full article

Mediterranean monk seal (Monachus monachus) sightings along the Lebanese coast were recorded between 2020 and 2025. This study aims to provide insights into the consistency of monk seal presence, their habitat use, and their feeding behaviour in the studied area. The research relied on photographic and video materials gathered from social media reports, as well as contributions from local fishers and divers. A total of 43 sightings were recorded, with photo-identification possible for 34 of these. The study confirmed the presence of at least three distinct individuals, including one adult female frequently utilizing marine caves in Amchit and Rawsheh. Video recordings of feeding behaviour revealed prey species such as grey mullet and octopus, which are also targeted by local fisheries, suggesting potential conflicts between the seals and the fishing sector. This study emphasizes the need for a more systematic, long-term monitoring approach, including the use of infrared cameras, to identify suitable habitats and more accurately assess seal presence. The research further recommends a region-wide effort to understand monk seal movements within the Levantine Basin and to support broader conservation initiatives for the species. Full article

Rabies is an acute, progressive, viral encephalitis. Warm-blooded vertebrates are susceptible. Major reservoirs reside in the Chiroptera and Carnivora. Among the latter, representatives include dogs, ferret badgers, foxes, jackals, mongooses, raccoons, and skunks. Within the Carnivora, pinnipeds represent a diverse group of >30 extant species. These marine mammals range from the Arctic to Antarctica, but there is no review about rabies in this group. Apparently, only a single 1980 case of rabies occurred from Svalbard in a ringed seal (Phoca hispida). However, in 2024, incidental cases appeared within South African Cape fur seals (Arctocephalus pusillus). Retrospective testing of archival material identified suspect cases dating back to 2022. Currently, more than 80 cases have been documented in seals. Moreover, a new 2025 focus appeared in Namibia and cases in Angola are predictable. Viral characterization supports spillover infection via rabid black-backed jackals (Lupulella mesomelas). A host shift appears likely, with ongoing seal intraspecific transmission. Given the unique nature of this epizootic, implications for the southern hemisphere abound. Unfortunately, comprehensive data are lacking on pinniped specimens examined outside of southern Africa. For example, although Antarctica is considered ‘rabies-free’, minimal international standards for support are unmet. No routine laboratory-based surveillance occurs. This enzootic rabies focus among seals in southern Africa presents unique challenges for the region and a rare opportunity for considering broader surveillance. Besides targeted parenteral vaccination of fur seals, local engagement involves vagrant species, including elephant (Mirounga leonina) and leopard seals (Hydrurga leptonyx). The void of regional pinniped surveillance, especially encompassing the Southern Ocean would require considerable proactive local resolution and much wider collaboration regarding future concerns to both public health and conservation biology. Full article

Seals are keystone animals in the Arctic and a valuable resource for Indigenous communities, but their virome is poorly understood. Through a preliminary investigation of the virome of seven North Atlantic bearded seals (Erignathus barbatus) from northwest Newfoundland, Canada, we discovered a new member of the Paramyxoviridae, a family including important animal pathogens. The complete coding genome sequence (15,898 nt) of the novel paramyxovirus, which we named bearded seal-associated paramyxovirus 1 (BSAPV-1), encoded five core paramyxoviral proteins—nucleoprotein, matrix, fusion, hemagglutinin-neuraminidase, and polymerase—and three proteins with no identifiable homologues that may represent the phosphoprotein, a small hydrophobic protein, and a transmembrane protein. Phylogenetic analysis, including BSAPV-1 and all 153 currently known paramyxoviral species, positioned the novel virus in a long-branched clade with Wenzhou Pacific spadenose shark paramyxovirus (Skoliovirinae, Scoliodonvirus scoliodontis), its closest relative (pairwise identity of the L protein: 30.1%). According to ICTV criteria, BSAPV-1 is likely the first member of a novel paramyxoviral subfamily. As the virus was found in combined tracheal/fecal swabs of a single animal, we could not conclude whether this is a seal virus or a virus associated with seal food. This study expands our knowledge about marine paramyxoviruses, and future studies should investigate BSAPV-1 ecology, spread, and host spectrum. Full article

Highly pathogenic avian influenza (HPAI) A(H5N1) clade 2.3.4.4b has recently emerged as a major threat to wildlife, agriculture, and public health due to its expanding host range and the increasing frequency of spillover into mammals. In July–August 2023, the mass death of over 3500 northern fur seals (Callorhinus ursinus) and at least one Steller sea lion (Eumetopias jubatus) was recorded on Tyuleniy Island in the Sea of Okhotsk, Russia. Two HPAI A(H5N1) viruses were isolated from fur seal carcasses and designated A/Northern_fur_seal/Russia_Tyuleniy/74/2023 and A/Northern_fur_seal/Russia_Tyuleniy/75/2023. Both viruses exhibited high pathogenicity in chickens (IVPI 2.7–3.0) and mice (MLD₅₀ 1.9–2.5 log₁₀EID₅₀/mL), with distinct differences in disease progression, histopathology, and organ tropism. Experimental infection of mice revealed that strain A/74/2023 induced more severe pulmonary and neurological lesions than A/75/2023. Whole-genome sequencing and phylogenetic analysis demonstrated close relatedness to HPAI H5N1 strains circulating in the Russian Far East and Japan from 2022 to 2023, with several mutations associated with mammalian adaptation, including NP-N319K and, in one isolate, PB2-E627K. According to our findings, northern fur seals (Callorhinus ursinus) on Tyuleniy Island acted as spillover hosts for the highly pathogenic avian influenza (HPAI) H5N1 virus of clade 2.3.4.4b. Furthermore, the high population density of fur seals and the extensive mortality observed during the outbreak highlight these animals’ potential role as another vessel for the evolution of avian influenza viruses. This study represents the first documented case of HPAI H5N1 in pinnipeds in the North Pacific region and supports previous reports indicating that pinnipeds, including northern fur seals, are highly susceptible to HPAI H5N1 clade 2.3.4.4b viruses. Full article

Reference intervals for clinical chemistry blood parameters are valuable for both individual diagnostics for animals in managed or veterinary care, and for evaluating wild population health. However, for marine mammals obtaining sufficient data from suitable groups or populations is logistically difficult. Here, we have assembled a large dataset of clinical chemistry results from free-living adult UK harbour seals (Phoca vitulina), analysed in the same commercial laboratory. We applied an open-source algorithm (available as the R package refineR, R version 4.5.2, refineR version 2.0.0) to produce robust reference intervals from these Real-World Data. This novel approach resulted in the generation of 95% reference intervals with 90% confidence bounds for 18 key chemistry parameters indicative of a range of physiological processes including, inflammation, nutritional status, kidney function and liver function. Reference intervals were also generated for triiodothyronine, the active thyroid hormone important in the regulation of metabolism. These intervals will provide critical baseline data for the assessment of harbour seal health as, to our knowledge, this is the largest dataset on which clinical chemistry reference intervals from wild-caught adult harbour seals have been based. Full article

Halarachne halichoeri mites are respiratory parasites of pinnipeds that have been recorded from different locations around the world, but not from the coast of Argentina. In this study, the presence of H. halichoeri on the southern elephant seal, Mirounga leonina, is documented for the first time in the Argentinean mainland, specifically in the Paraná River on the Buenos Aires coast. A total of 4130 adult and immature mites (90.4% larvae, 0% nymphs, 9.2% females and 0.4% males) were collected from the nose and nasopharyngeal cavity of a stranded juvenile male during a necropsy. The species was identified using scanning electron microscopy (SEM) and stereomicroscope photography, and the morphological characteristics of the females and males are shown. Also, images of the male are shown for the first time, with observable details of traits. We also propose a method for simple sex recognition. Finally, we provide a revision of global records of geographic distribution of H. halichoeri in wild marine mammals. The present record of occurrence of the species H. halichoeri in Argentina expands our knowledge about the distribution area known to date for this species of marine parasite. Full article

The assessment of animal welfare in rehabilitation settings is a critical aspect of effective care, yet typical metrics often fail to fully capture rehabilitating animals’ emotional experiences in a non-invasive way. Anticipatory behavior has emerged as a promising animal welfare indicator, reflecting an animal’s perceived need for rewards based on available opportunities in their environment. By tracking anticipatory responses, caretakers can gain insight into an animal’s reward sensitivity and use this information to guide management interventions. This study investigated the effects of enrichment type on anticipatory behavior in fourteen, rehabilitating harbor seal pups (Phoca vitulina richardii). We provided pups with daily sessions of either structural or cognitive enrichment and recorded their behavioral responses. During scheduled feeding sessions, we identified behaviors that emerged as anticipatory, then measured the frequency and duration of anticipatory behavior prior to the feeds to assess how enrichment types influenced the seals’ reward sensitivity, and thus their welfare. While enrichment interaction did not directly modulate anticipatory behavior, we observed a trend suggesting that exposure to cognitive enrichment reduced anticipatory behavior duration compared to structural enrichment. These findings align with previous research in zoo settings, where cognitive enrichment has been linked to improved welfare through reduced anticipatory behavior, though this effect has not been explored in a wildlife rehabilitation context. This study highlights the value of anticipatory behavior as a practical welfare assessment tool in rehabilitation settings and underscores the potential for enrichment, particularly cognitive, to improve welfare in rehabilitating marine mammals. Full article

The spotted seal (Phoca largha), the only pinniped species capable of natural breeding in Chinese waters, serves as a flagship species for the Bohai Sea and the Yellow Sea marine ecosystems. Changes in its population numbers are an important indicator of the status of the marine ecological environment. However, when using traditional monitoring methods, such as telescope inspections and routine unmanned aerial vehicle (UAV) photography, it is difficult to accurately grasp the changes in spotted seal populations. Here, we document the use of infrared imaging with a UAV to facilitate round-the-clock monitoring of spotted seal numbers in a protected area. This approach revealed that late night and early morning (22:00–05:00) were peak times for their haul-out activity, with a maximum count of 166. This provides a new idea for the investigation and monitoring of marine mammals and the protection of marine ecosystems. Full article

Neuromuscular blocking agents (NMBAs) are essential in intraocular surgeries to improve surgical conditions and ensure optimal ventilation. However, residual blockade can pose significant risks, particularly in pinnipeds due to their unique diving physiology. This case report describes the use of sugammadex for reversing rocuronium and AMG for monitoring neuromuscular block (NMB) in a California sea lion undergoing lensectomy. The objective is to evaluate the feasibility and safety of sugammadex for reversal of rocuronium-induced neuromuscular blockade and acceleromyography (AMG) for monitoring neuromuscular function in pinnipeds, with the goal of improving anesthetic management and recovery. Rocuronium (0.3 mg/kg IV) was used to achieve complete NMB, and an additional 0.1 mg/kg IV was administered to prolong the block. Sugammadex (1 mg/kg IV) reversed the NMB, with recovery within 90 s. Neuromuscular function was monitored using AMG, with the ulnar nerve of the foreflipper as the stimulation site. AMG allowed for an objective assessment of neuromuscular function, ensuring accurate titration of the NMBA and reversal agent. This is the first report documenting the use of sugammadex for the reversal of rocuronium and AMG for neuromuscular monitoring in a sea lion. This successful application highlights the potential of these techniques to improve anesthesia protocols, patient safety, and welfare in marine mammal medicine. Full article

The highly pathogenic avian influenza H5N1 2.3.4.4b clade virus has caused widespread outbreaks across South America, primarily affecting seabirds, poultry, and marine mammals. The virus likely reached the continent through migratory birds from North America, initially spreading along the Pacific coast before advancing into Atlantic-bordering countries such as Argentina, Uruguay, and Brazil. This study investigated the dynamics of H5N1 strains in Uruguay during outbreaks from February and October 2023. We analyzed an updated South American database, including a newly sequenced viral genome from a royal tern (Thalasseus maximus) collected at the end of the outbreaks. Phylogeographic reconstruction revealed two distinct South American phylogroups comprising Uruguayan strains: one mainly driven by wild birds and poultry, with the royal tern strain clustering with Brazilian isolates, and another primarily associated with marine mammals, displaying adaptive residues in the PB2 protein. In Uruguay, these phylogroups delineate two main transmission routes: (i) an avian-derived pathway originating in Argentina and (ii) a pinniped-derived route from Chile. Brazil, initially colonized via the Argentine route, later emerged as a secondary source for Uruguay. This host-pathway interplay underscores the virus’s cross-species potential and highlights the need for coordinated regional surveillance within a One Health framework to mitigate zoonotic risks. Full article