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Three Odontaspis ferox (confirmed by mtDNA barcoding) were found in the English Channel and Celtic Sea in 2023 at Lepe, UK (50.7846, −1.3508), Kilmore Quay, Ireland (52.1714, −6.5937), and Lyme Bay, UK (50.6448, −2.9302). These are the first records of O. ferox in either country, and extend the species' range by over three degrees of latitude, to >52° N. They were ~275 (female), 433 (female), and 293 cm (male) total length, respectively. These continue a series of new records, possibly indicative of a climate change−induced shift in the species' range. [ABSTRACT FROM AUTHOR]

Simple Summary: The presence of round to oval, single to multiple, hyaline eosinophilic globules inside the cytoplasmic of the hepatocytes of cetaceans are unknown. Therefore, this article aims to describe their occurrence and characterize their features using different laboratorial techniques. A total of 95 out of 115 cetaceans (83%) from 16 different species exhibited intracytoplasmic eosinophilic globules (IEGs) within the hepatocytes. These globules were positive for fibrinogen (FB, 97%), albumin (Alb, 85%), and α1-antitrypsine (A1AT, 53%), with the positivity for FB and A1AT correlated with live-stranding, hepatic congestion and a good nutritional status. The IEGs in 36 cetaceans that died due to bycatch were, all except one, FB-positive and A1AT-negative. The IEGs exhibited morphologic and compositional variations at the ultrastructural level, suggesting various stages of development. The proteomic analyses confirmed an association between the IEGs and acute phase proteins, suggesting a relationship between acute stress (i.e., bycatch), disease, and cellular protective mechanisms. The nature, etiopathogenesis, and clinicopathologic relevance of the prevalent intracytoplasmic eosinophilic globules (IEGs) within hepatocytes of cetaceans are unknown. This study aims to evaluate the presence and characterize the IEGs in the hepatocytes of cetaceans using histochemical and immunohistochemical electron microscopy, Western blot, lectin histochemistry, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry techniques. A total of 95/115 (83%) animals (16 species) exhibited histologically evident intracytoplasmic round to oval, single to multiple, hyaline eosinophilic globules within the hepatocytes. These globules were largely PAS-positive, diastase resistant, and were immunopositive for fibrinogen (FB, 97%), albumin (Alb, 85%), and α1-antitrypsine (A1AT, 53%). The IEG positivity for FB and A1AT were correlated with live-stranding, hepatic congestion and a good nutritional status. The cetaceans lacking IEGs were consistently dead stranded and had poor body conditions. The IEGs in 36 bycaught cetaceans were, all except one, FB-positive and A1AT-negative. The IEGs exhibited morphologic and compositional variations at the ultrastructural level, suggesting various stages of development and/or etiopathogenesis(es). The glycocalyx analysis suggested an FB- and A1AT-glycosylation pattern variability between cetaceans and other animals. The proteomic analyses confirmed an association between the IEGs and acute phase proteins, suggesting a relationship between acute stress (i.e., bycatch), disease, and cellular protective mechanisms, allowing pathologists to correlate this morphological change using the acute hepatocytic cell response under certain stress conditions. [ABSTRACT FROM AUTHOR]

Between the 8th January and the 25th February 2016, the largest sperm whale Physeter macrocephalus mortality event ever recorded in the North Sea occurred with 30 sperm whales stranding in five countries within six weeks. All sperm whales were immature males. Groups were stratified by size, with the smaller animals stranding in the Netherlands, and the largest in England. The majority (n = 27) of the stranded animals were necropsied and/or sampled, allowing for an international and comprehensive investigation into this mortality event. The animals were in fair to good nutritional condition and, aside from the pathologies caused by stranding, did not exhibit significant evidence of disease or trauma. Infectious agents were found, including various parasite species, several bacterial and fungal pathogens and a novel alphaherpesvirus. In nine of the sperm whales a variety of marine litter was found. However, none of these findings were considered to have been the primary cause of the stranding event. Potential anthropogenic and environmental factors that may have caused the sperm whales to enter the North Sea were assessed. Once sperm whales enter the North Sea and head south, the water becomes progressively shallower (<40 m), making this region a global hotspot for sperm whale strandings. We conclude that the reasons for sperm whales to enter the southern North Sea are the result of complex interactions of extrinsic environmental factors. As such, these large mortality events seldom have a single ultimate cause and it is only through multidisciplinary, collaborative approaches that potentially multifactorial large-scale stranding events can be effectively investigated. [ABSTRACT FROM AUTHOR]

The globally distributed sperm whale (Physeter macrocephalus) has a partly matrilineal social structure with predominant male dispersal. At the beginning of 2016, a total of 30 male sperm whales stranded in five different countries bordering the southern North Sea. It has been postulated that these individuals were on a migration route from the north to warmer temperate and tropical waters where females live in social groups. By including samples from four countries (n = 27), this event provided a unique chance to genetically investigate the maternal relatedness and the putative origin of these temporally and spatially co-occuring male sperm whales. To utilize existing genetic resources, we sequenced 422 bp of the mitochondrial control region, a molecular marker for which sperm whale data are readily available from the entire distribution range. Based on four single nucleotide polymorphisms (SNPs) within the mitochondrial control region, five matrilines could be distinguished within the stranded specimens, four of which matched published haplotypes previously described in the Atlantic. Among these male sperm whales, multiple matrilineal lineages co-occur. We analyzed the population differentiation and could show that the genetic diversity of these male sperm whales is comparable to the genetic diversity in sperm whales from the entire Atlantic Ocean. We confirm that within this stranding event, males do not comprise maternally related individuals and apparently include assemblages of individuals from different geographic regions. [ABSTRACT FROM AUTHOR]

The globally distributed sperm whale ( Physeter macrocephalus ) has a partly matrilineal social structure with predominant male dispersal. At the beginning of 2016, a total of 30 male sperm whales stranded in five different countries bordering the southern North Sea. It has been postulated that these individuals were on a migration route from the north to warmer temperate and tropical waters where females live in social groups. By including samples from four countries (n = 27), this event provided a unique chance to genetically investigate the maternal relatedness and the putative origin of these temporally and spatially co-occuring male sperm whales. To utilize existing genetic resources, we sequenced 422 bp of the mitochondrial control region, a molecular marker for which sperm whale data are readily available from the entire distribution range. Based on four single nucleotide polymorphisms (SNPs) within the mitochondrial control region, five matrilines could be distinguished within the stranded specimens, four of which matched published haplotypes previously described in the Atlantic. Among these male sperm whales, multiple matrilineal lineages co-occur. We analyzed the population differentiation and could show that the genetic diversity of these male sperm whales is comparable to the genetic diversity in sperm whales from the entire Atlantic Ocean. We confirm that within this stranding event, males do not comprise maternally related individuals and apparently include assemblages of individuals from different geographic regions. [ABSTRACT FROM AUTHOR]

Oscillations in the Earth's temperature and the subsequent retreating and advancing of ice-sheets around the polar regions are thought to have played an important role in shaping the distribution and genetic structuring of contemporary high-latitude populations. After the Last Glacial Maximum (LGM), retreating of the ice-sheets would have enabled early colonizers to rapidly occupy suitable niches to the exclusion of other conspecifics, thereby reducing genetic diversity at the leading-edge. Bottlenose dolphins (genus Tursiops) form distinct coastal and pelagic ecotypes, with finer-scale genetic structuring observed within each ecotype. We reconstruct the postglacial colonization of the Northeast Atlantic (NEA) by bottlenose dolphins using habitat modeling and phylogenetics. The AquaMaps model hindcasted suitable habitat for the LGM in the Atlantic lower latitude waters and parts of the Mediterranean Sea. The time-calibrated phylogeny, constructed with 86 complete mitochondrial genomes including 30 generated for this study and created using a multispecies coalescent model, suggests that the expansion to the available coastal habitat in the NEA happened via founder events starting ~15 000 years ago (95% highest posterior density interval: 4 900–26 400). The founders of the 2 distinct coastal NEA populations comprised as few as 2 maternal lineages that originated from the pelagic population. The low effective population size and genetic diversity estimated for the shared ancestral coastal population subsequent to divergence from the pelagic source population are consistent with leading-edge expansion. These findings highlight the legacy of the Late Pleistocene glacial cycles on the genetic structuring and diversity of contemporary populations. [ABSTRACT FROM AUTHOR]

Long-finned pilot whales (Globicephala melas) are rare visitors to the southern North Sea, but recently two individual strandings occurred on the Dutch coast. Both animals shared the same, unusual cause of death: asphyxiation from a common sole (Solea solea) stuck in their nasal cavity. This is a rare cause of death in cetaceans. Whilst asphyxiation has been reported in smaller odontocetes, there are no recent records of this occurring in Globicephala species. Here we report the stranding, necropsy and diet study results as well as discuss the unusual nature of this phenomenon. Flatfish are not a primary prey species for pilot whales and are rarely eaten by other cetaceans, such as harbour porpoises (Phocoena phocoena), in which there are several reports of asphyxiation due to airway obstruction by soles. This risk may be due to the fish’s flexible bodies which can enter small cavities either actively in an attempt to escape or passively due to the whale ‘coughing’ or ‘sneezing’ to rid itself of the blockage of the trachea. It is also possible that the fish enter the airways whilst the whale is re-articulating the larynx after trying to ingest large, oddly shaped prey. It is unlikely that the soles entered the airways after the death of the whales and we believe therefore that they are responsible for the death of these animals. [ABSTRACT FROM AUTHOR]

Poxvirus infections in marine mammals have been mainly reported through their clinical lesions and electron microscopy (EM). Poxvirus particles in association with such lesions have been demonstrated by EM and were previously classified as two new viruses, cetacean poxvirus 1 (CePV-1) and cetacean poxvirus 2 (CePV-2). In this study, epidermal pox lesions in cetaceans stranded in South West England (Cornwall) between 2008 and 2012 were investigated by electron microscopy and molecular analysis. PCR and sequencing of a highly conserved region within the viral DNA polymerase gene ruled out both parapox- and orthopoxviruses. Moreover, phylogenetic analysis of the PCR product clustered the sequences with those previously described as cetacean poxviruses. However, taking the close genetic distance of this gene fragment across the family of poxviridae into account, it is reasonable to postulate further, novel cetacean poxvirus species. The nucleotide similarity within each cluster (tentative species) detected ranged from 98.6% to 100%, whilst the similarity between the clusters was no more than 95%. The detection of several species of poxvirus in different cetacean species confirms the likelihood of a heterogeneous cetacean poxvirus genus, comparable to the heterogeneity observed in other poxvirus genera. [ABSTRACT FROM AUTHOR]

There is increasing evidence that the distributions of a large number of species are shifting with global climate change as they track changing surface temperatures that define their thermal niche. Modelling efforts to predict species distributions under future climates have increased with concern about the overall impact of these distribution shifts on species ecology, and especially where barriers to dispersal exist. Here we apply a bio-climatic envelope modelling technique to investigate the impacts of climate change on the geographic range of ten cetacean species in the eastern North Atlantic and to assess how such modelling can be used to inform conservation and management. The modelling process integrates elements of a species' habitat and thermal niche, and employs 'hindcasting' of historical distribution changes in order to verify the accuracy of the modelled relationship between temperature and species range. If this ability is not verified, there is a risk that inappropriate or inaccurate models will be used to make future predictions of species distributions. Of the ten species investigated, we found that while the models for nine could successfully explain current spatial distribution, only four had a good ability to predict distribution changes over time in response to changes in water temperature. Applied to future climate scenarios, the four species-specific models with good predictive abilities indicated range expansion in one species and range contraction in three others, including the potential loss of up to 80% of suitable white-beaked dolphin habitat. Model predictions allow identification of affected areas and the likely time-scales over which impacts will occur. Thus, this work provides important information on both our ability to predict how individual species will respond to future climate change and the applicability of predictive distribution models as a tool to help construct viable conservation and management strategies. [ABSTRACT FROM AUTHOR]

With global increases in anthropogenic pressures on wildlife populations comes a responsibility to manage them effectively. The assessment of marine ecosystem health is challenging and often relies on monitoring indicator species, such as cetaceans. Most cetaceans are however highly mobile and spend the majority of their time hidden from direct view, resulting in uncertainty on even the most basic population metrics. Here, we discuss the value of long-term and internationally combined stranding records as a valuable source of information on the demographic and mortality trends of the harbour porpoise (Phocoena phocoena) in the North Sea. We analysed stranding records (n = 16,181) from 1990 to 2017 and demonstrate a strong heterogeneous seasonal pattern of strandings throughout the North Sea, indicative of season-specific distribution or habitat use, and season-specific mortality. The annual incidence of strandings has increased since 1990, with a notable steeper rise particularly in the southern North Sea since 2005. A high density of neonatal strandings occurred specifically in the eastern North Sea, indicative of areas important for calving, and large numbers of juvenile males stranded in the southern parts, indicative of a population sink or reflecting higher male dispersion. These findings highlight the power of stranding records to detect potentially vulnerable population groups in time and space. This knowledge is vital for managers and can guide, for example, conservation measures such as the establishment of time-area-specific limits to potentially harmful human activities, aiming to reduce the number and intensity of human-wildlife conflicts. • International data synthesis to understand wildlife mortality and demographic trends • We demonstrate the value of long-term surveillance exemplified by stranding records. • Our analyses indicate potential vulnerable population groups in time and space. • Analytical methods allow establishment of robust baseline of spatiotemporal variation. • Results guide conservation measures aiming to reduce human-wildlife conflicts at sea. [ABSTRACT FROM AUTHOR]

• 347 harbor porpoise PCB congener profiles were analysed. • Juveniles had higher proportions of less chlorinated congeners than adults. • Porpoises on the West coast of England and Wales had higher ratios of persistent PCBs. • To assess risk the toxicity of different congener profiles at different life stages needs to be quantified. Polychlorinated biphenyls (PCBs) are a group of 209 persistent and bio-accumulative toxic pollutants present as complex mixtures in human and animal tissues. Harbor porpoises accumulate some of the highest levels of PCBs because they are long-lived mammals that feed at a high trophic level. Studies typically use the sum of a suite of individual chlorobiphenyl congeners (CBs) to investigate PCBs in wildlife. However, toxic effects and thresholds of CB congeners differ, therefore population health risks of exposure may be under or over-estimated dependent on the congener profiles present. In this study, we found congener profiles varied with age, sex and location, particularly between adult females and juveniles. We found that adult females had the highest proportions of octa -chlorinated congeners whilst juveniles had the highest proportions of tri- and tetra- chlorinated congeners. This is likely to be a consequence of pollutant offloading between mothers and calves during lactation. Analysis of the individual congener toxicities found that juveniles were exposed to a more neurotoxic CB mixture at a time when they were most vulnerable to its effects. These findings are an important contribution towards our understanding of variation in congener profiles and the potential effects and threats of PCB exposure in cetaceans. [ABSTRACT FROM AUTHOR]

Neisseria animaloris is considered to be a commensal of the canine and feline oral cavities. It is able to cause systemic infections in animals as well as humans, usually after a biting trauma has occurred. We recovered N. animaloris from chronically inflamed bite wounds on pectoral fins and tailstocks, from lungs and other internal organs of eight harbour porpoises. Gross and histopathological evidence suggest that fatal disseminated N. animaloris infections had occurred due to traumatic injury from grey seals. We therefore conclude that these porpoises survived a grey seal predatory attack, with the bite lesions representing the subsequent portal of entry for bacteria to infect the animals causing abscesses in multiple tissues, and eventually death. We demonstrate that forensic microbiology provides a useful tool for linking a perpetrator to its victim. Moreover, N. animaloris should be added to the list of potential zoonotic bacteria following interactions with seals, as the finding of systemic transfer to the lungs and other tissues of the harbour porpoises may suggest a potential to do likewise in humans. [ABSTRACT FROM AUTHOR]

Environmental conditions can shape genetic and morphological divergence. Release of new habitats during historical environmental changes was a major driver of evolutionary diversification. Here, forces shaping population structure and ecotype differentiation ('pelagic' and 'coastal') of bottlenose dolphins in the North-east Atlantic were investigated using complementary evolutionary and ecological approaches. Inference of population demographic history using approximate Bayesian computation indicated that coastal populations were likely founded by the Atlantic pelagic population after the Last Glacial Maxima probably as a result of newly available coastal ecological niches. Pelagic dolphins from the Atlantic and the Mediterranean Sea likely diverged during a period of high productivity in the Mediterranean Sea. Genetic differentiation between coastal and pelagic ecotypes may be maintained by niche specializations, as indicated by stable isotope and stomach content analyses, and social behaviour. The two ecotypes were only weakly morphologically segregated in contrast to other parts of the World Ocean. This may be linked to weak contrasts between coastal and pelagic habitats and/or a relatively recent divergence. We suggest that ecological opportunity to specialize is a major driver of genetic and morphological divergence. Combining genetic, ecological and morphological approaches is essential to understanding the population structure of mobile and cryptic species. [ABSTRACT FROM AUTHOR]