Validation of Fecal Glucocorticoid Metabolites as Non-Invasive Markers for Monitoring Stress in Common Buzzards (Buteo buteo)

For wild animals, being in captivity in wildlife centers can cause considerable stress. Therefore, it is necessary to establish and validate non-invasive tools to measure chronic stress during rehabilitation. Eight Common Buzzards which lived in permanent husbandry were placed individually into prepared aviaries and their feces were collected before, during and after a stress event for biological validation over a period of seven days. The extracted fecal glucocorticoid metabolites (fGCMs) were analyzed with three different enzyme immune assays (EIA) to find the most suitable one. Additionally, we aimed to investigate the stability of fGCM levels after defecation because further metabolization by bacterial enzymes can lead to changed results. The Cortisone-EIA performed best in males and females and showed that the stress event led to an fGCM increase of 629% (557% in females and 702% in males) in relation to basal values. We found no significant differences between the sexes, but observed significant differences between different times of day. FGCM concentration significantly changed after eight hours at room temperature. Our study successfully validated the non-invasive measurement of fGCM as a stress indicator in Common Buzzards and could therefore lay the foundation for future studies providing new insights for animal welfare research in Buzzards.

Heartworm and seal louse: Trends in prevalence, characterisation of impact and transmission pathways in a unique parasite assembly on seals in the North and Baltic Sea

The ectoparasitic seal louse, Echinophthirius horridus infects harbour (Phoca vitulina) and grey seals (Halichoerus grypus) in the North and Baltic Sea. The endoparasitic heartworm Acanthocheilonema spirocauda parasitizes the right heart and blood vessels of harbour seals. The complete lifecycle of the heartworm is not entirely understood although the seal louse is assumed to serve as vector for its transmission. Knowledge about the impact of both parasite species on host health are scarce. In this study, necropsy data and archived parasites of harbour and grey seals in German waters were analysed to determine long-term seal louse (SLP) and heartworm prevalence (HWP) from 2014 to 2021. Histology, microbiology and scanning electron microscopy (SEM) were applied on seal louse infected and uninfected skin to investigate associated lesions and the health impact. During the study period, HWP in harbour seals was 13%, the SLP in harbour seals was 4% and in grey seals 10%. HWP of harbour seals was significantly higher during the winter months compared to the summer. SLP in adults was significantly higher in comparison to juvenile harbour seals. SLP varied significantly between grey seals from the North and Baltic Sea. Filarial nematodes were detected in the haemocoel, pharynx, and intestine of E. horridus highlighting the seal louse as vector for heartworms. Alopecia and folliculitis were associated with the attachment posture of E. horridus and microbiological investigations isolated bacteria commonly associated with folliculitis.

Population genomics of the white-beaked dolphin (Lagenorhynchus albirostris): Implications for conservation amid climate-driven range shifts

Climate change is rapidly affecting species distributions across the globe, particularly in the North Atlantic. For highly mobile and elusive cetaceans, the genetic data needed to understand population dynamics are often scarce. Cold-water obligate species such as the white-beaked dolphin (Lagenorhynchus albirostris) face pressures from habitat shifts due to rising sea surface temperatures in addition to other direct anthropogenic threats. Unravelling the genetic connectivity between white-beaked dolphins across their range is needed to understand the extent to which climate change and anthropogenic pressures may impact species-wide genetic diversity and identify ways to protect remaining habitat. We address this by performing a population genomic assessment of white-beaked dolphins using samples from much of their contemporary range. We show that the species displays significant population structure across the North Atlantic at multiple scales. Analysis of contemporary migration rates suggests a remarkably high connectivity between populations in the western North Atlantic, Iceland and the Barents Sea, while two regional populations in the North Sea and adjacent UK and Irish waters are highly differentiated from all other clades. Our results have important implications for the conservation of white-beaked dolphins by providing guidance for the delineation of more appropriate management units and highlighting the risk that local extirpation may have on species-wide genetic diversity. In a broader context, this study highlights the importance of understanding genetic structure of all species threatened with climate change-driven range shifts to assess the risk of loss of species-wide genetic diversity.

Human-Wildlife Interaction-A Social Survey

With the results of a survey presented in this paper, we provide insight into public attitudes towards dealing with wildlife. Based on 1569 data sets derived from participating stakeholders, we inquired about the individual experience the participants had made with wild animals, and asked about their personal engagement, attitude towards management, and emotions involved and tried to evaluate basic contextual knowledge. As a result, we discovered a positive effect showing that a strong opinion about dealing with wildlife is associated with increasing contextual knowledge. People that are experienced in and engaged in wildlife conservation expressed significantly stronger positive emotions in this context. We conclude that education is essential in dealing with wildlife responsibly and that positive emotions are a main trigger for such engagement. The results of the survey underline that a combination of contextual knowledge and a positive attitude towards wildlife leads to a higher awareness of possible conflicts between humans and wildlife. Furthermore, these criteria are crucial when developing strategies that strive for a sustainable coexistence.

Gene expression and trace elements in Greenlandic ringed seals (Pusa hispida)

Marine top predators such as ringed seals biomagnify environmental contaminants; and with the increasing human activities in the Arctic, ringed seals are exposed to biologically significant concentrations of trace elements resulting in reproductive impairment, immunosuppression, and neurological damages. Little is known about the molecular effects of heavy metals on these vulnerable apex predators suffering from a rapidly changing Arctic with significant loss of sea-ice. In the present study, concentrations of cadmium (Cd), mercury (Hg) and selenium (Se) were measured in liver of sixteen Greenlandic ringed seals (nine adults and seven subadults) together with molecular biomarkers involved in bio-transformation, oxidative stress, endocrine disruption and immune activity in blood and blubber. The concentrations of trace elements increased in the following order: Hg > Se > Cd with levels of mercury and selenium being highest in adults. Aryl hydrocarbon receptor nuclear translocator (ARNT), peroxisome proliferator activated receptor alpha (PPARα, estrogen receptor alpha (ESR1), thyroid hormone receptor alpha (TRα) and interleukin - 2 (IL-2) mRNA transcript levels were highest in blubber, while heat shock protein 70 (HSP70) and interleukin - 10 (IL-10) were significantly higher in blood. There were no significant correlations between the concentrations of trace elements and mRNA transcript levels suggesting that stressors other than the trace elements investigated are responsible for the changes in gene expression levels. Since Hg seems to increase in Greenlandic ringed seals, there is a need to re-enforce health monitoring of this ringed seal population.

Survival and adaptation of Streptococcus phocae in host environments

Marine mammals are sentinel species representing the "health" of our oceans on which we are dependent. There are many threats to marine mammals including infectious diseases that increase with climate change and pollution of the marine environment. Streptococcus phocae has frequently been isolated from diseased or dead marine mammals. However, its pathogenicity and contribution to disease in marine mammals is still unknown. As bacteria including (potential) pathogens has to deal with different host environments during colonization or infection, we investigated the survival of S. phocae in fresh porcine and phocid blood, in seawater and in the presence of macrophages and (epithelial) cells from harbor seals and pigs. Furthermore, we tested adherence on and invasion of different (marine) mammalian cells by S. phocae. Our results showed that S. phocae can survive in seawater for at least 11 and 28 days at 16°C and 4°C, respectively. It is able to grow in blood of harbor and grey seals, but not in porcine blood. Furthermore, S. phocae is adherent and invasive to cells from seals and pigs, while the portion of invasive cells was higher in seal derived cells. Macrophages of harbor seals were more efficient in killing S. phocae than porcine macrophages. Our results indicate that S. phocae has strategies enabling it to adapt to the marine environment and seal hosts.

First evidence of widespread anticoagulant rodenticide exposure of the Eurasian otter (Lutra lutra) in Germany

Exposure of wildlife to anticoagulant rodenticides (ARs) has been extensively documented for species directly or indirectly linked to pest rodents via the terrestrial food web. Recently, the scientific focus extended to a former blind spot, namely AR emissions to the aquatic environment, and provided clear evidence of AR residues in freshwater fish. As second-generation ARs are likely to be transferred along the aquatic food chain, a total of 122 Eurasian otter (Lutra lutra) individuals found dead in Germany between 2005 and 2021 were investigated to shed more light on resultant environmental risks. Target analytes comprised one pharmaceutical and eight biocidal anticoagulants, as well as one suspected bait impurity. Notably, all target compounds were detected in the analyzed livers of otters, a primarily piscivorous top predator and indicator species for the aquatic environment, strictly protected by conservation laws. In regions with pronounced rodent control measures, otters were frequently exposed to biocidal ARs. The elevated AR levels measured in multiple otters, compared to freshwater fish, hinted at biomagnification of second-generation ARs within the aquatic food web. The results indicated that risk mitigation measures implemented in Germany within the biocidal product authorization may not be sufficient to protect aquatic non-target wildlife from AR exposure, challenging the effectiveness of current regulatory measures.

Malicious Mites-Sarcoptes scabiei in Raccoon Dogs (Nyctereutes procyonoides) in Schleswig-Holstein, Germany

Sarcoptic mange was detected in five free-ranging raccoon dogs (Nyctereutes procyonoides) in the federal state of Schleswig-Holstein, Germany, during a health assessment study of invasive species, including raccoon dogs, carried out between 2021 and 2022. Four raccoon dogs showed severe lesions, including extensive alopecia with thickening and hyperpigmentation of the skin (lichenification). The fifth animal was less affected, showing only thinning of the hair coat in multiple body locations. Skin scrapings were performed and confirmed the presence of Sarcoptes scabiei. Histopathology of the skin revealed diffuse epidermal hyperplasia and hyperkeratosis, mild eosinophilic dermatitis, and varying amounts of intralesional mites. Staphylococcus pseudintermedius and Corynebacterium auriscanis were detected in the skin samples of the affected animals, indicating a secondary bacterial infection. The source of sarcoptic mange remains unclear; interspecies transmission via direct or indirect contact seems likely. Raccoon dogs are therefore a potential vector for sarcoptic mange, and their behaviour could contribute to disease spread and persistence.

Characterizing the marine mammal exposome by iceberg modeling, linking chemical analysis and in vitro bioassays

The present study complements work on mixture effects measured with in vitro bioassays of passive equilibrium sampling extracts using the silicone polydimethylsiloxane (PDMS) in organs from marine mammals with chemical profiling. Blubber, liver, kidney and brain tissues of harbor porpoise (Phocoena phocoena), harbor seal (Phoca vitulina), ringed seal (Phoca hispida) and orca (Orcinus orca) from the North and Baltic Seas were investigated. We analyzed 117 chemicals including legacy and emerging contaminants using gas chromatography-high resolution mass spectrometry and quantified 70 of those chemicals in at least one sample. No systematic differences between the organs were found. Only for single compounds a clear distribution pattern was observed. For example, 4,4'-dichlorodiphenyltrichloroethane, enzacamene and etofenprox were mainly detected in blubber, whereas tonalide and the hexachlorocyclohexanes were more often found in liver. Furthermore, we compared the chemical profiling with the bioanalytical results using an iceberg mixture model, evaluating how much of the biological effect could be explained by the analyzed chemicals. The mixture effect predicted from the quantified chemical concentrations explained 0.014-83% of the aryl hydrocarbon receptor activating effect (AhR-CALUX), but less than 0.13% for the activation of the oxidative stress response (AREc32) and peroxisome-proliferator activated receptor (PPARγ). The quantified chemicals also explained between 0.044-45% of the cytotoxic effect measured with the AhR-CALUX. The largest fraction of the observed effect was explained for the orca, which was the individuum with the highest chemical burden. This study underlines that chemical analysis and bioassays are complementary to comprehensively characterize the mixture exposome of marine mammals.

Pathomorphological Findings and Infectious Diseases in Selected European Brown Hare (Lepus europaeus Pallas, 1778) Populations from Schleswig-Holstein, Germany

In the northernmost German federal state Schleswig-Holstein, populations of European brown hares (Lepus europaeus Pallas, 1778) show diverse densities and varying courses over the years. To examine differences in pathomorphological findings and infectious diseases as possible reasons for varying population dynamics, we assessed 155 hunted hares from three locations in Schleswig-Holstein from 2016 to 2020. We investigated the association of location, year, age, and sex of animals to certain pathomorphological findings and infectious diseases. Frequent pathomorphological findings were intestinal parasites (63.9%), hepatitis (55.5%), nephritis (31.0%), steatitis (23.2%), enteritis (13.5%), and pneumonia (5.2%). Body condition differed significantly between locations, and the prevalence of pneumonia was significantly higher in females. Enteritis was not detected in 2019, when much more juveniles were sampled. Hepatitis and nephritis occurred significantly more often in 2016 and among adults. Additionally, more adults showed hepatitis with concurrent serotitre for European brown hare syndrome virus (EBHSV), while intestinal parasitosis as well as high excretion rates of coccidia were more common in juveniles. Sampled animals showed high infection rates with Eimeria spp. (96.1%), Trichostrongylus spp. (52.0%), Graphidium strigosum (41.2%), and a high seroprevalence (90.9%) for EBHSV, without severe symptoms. This study revealed a low prevalence of infectious pathogens, but a high prevalence of chronic inflammations of unknown origin in the tested brown hare populations. Overall, our results indicate a rather minor importance of infectious diseases for observed population dynamics of analysed hare populations in Schleswig-Holstein.

Wild harbour porpoises startle and flee at low received levels from acoustic harassment device

Acoustic Harassment Devices (AHD) are widely used to deter marine mammals from aquaculture depredation, and from pile driving operations that may otherwise cause hearing damage. However, little is known about the behavioural and physiological effects of these devices. Here, we investigate the physiological and behavioural responses of harbour porpoises (Phocoena phocoena) to a commercial AHD in Danish waters. Six porpoises were tagged with suction-cup-attached DTAGs recording sound, 3D-movement, and GPS (n = 3) or electrocardiogram (n = 2). They were then exposed to AHDs for 15 min, with initial received levels (RL) ranging from 98 to 132 dB re 1 µPa (rms-fast, 125 ms) and initial exposure ranges of 0.9-7 km. All animals reacted by displaying a mixture of acoustic startle responses, fleeing, altered echolocation behaviour, and by demonstrating unusual tachycardia while diving. Moreover, during the 15-min exposures, half of the animals received cumulative sound doses close to published thresholds for temporary auditory threshold shifts. We conclude that AHD exposure at many km can evoke both startle, flight and cardiac responses which may impact blood-gas management, breath-hold capability, energy balance, stress level and risk of by-catch. We posit that current AHDs are too powerful for mitigation use to prevent hearing damage of porpoises from offshore construction.

Implications of porpoise echolocation and dive behaviour on passive acoustic monitoring

Harbour porpoises are visually inconspicuous but highly soniferous echolocating marine predators that are regularly studied using passive acoustic monitoring (PAM). PAM can provide quality data on animal abundance, human impact, habitat use, and behaviour. The probability of detecting porpoise clicks within a given area (P̂) is a key metric when interpreting PAM data. Estimates of P̂ can be used to determine the number of clicks per porpoise encounter that may have been missed on a PAM device, which, in turn, allows for the calculation of abundance and ideally non-biased comparison of acoustic data between habitats and time periods. However, P̂ is influenced by several factors, including the behaviour of the vocalising animal. Here, the common implicit assumption that changes in animal behaviour have a negligible effect on P̂ between different monitoring stations or across time is tested. Using a simulation-based approach informed by acoustic biologging data from 22 tagged harbour porpoises, it is demonstrated that porpoise behavioural states can have significant (up to 3× difference) effects on P̂. Consequently, the behavioural state of the animals must be considered in analysis of animal abundance to avoid substantial over- or underestimation of the true abundance, habitat use, or effects of human disturbance.

Evolutionary history and seascape genomics of Harbour porpoises (Phocoena phocoena) across environmental gradients in the North Atlantic and adjacent waters

The Harbour porpoise (Phocoena phocoena) is a highly mobile cetacean species primarily occurring in coastal and shelf waters across the Northern hemisphere. It inhabits heterogeneous seascapes broadly varying in salinity and temperature. Here, we produced 74 whole genomes at intermediate coverage to study Harbour porpoise's evolutionary history and investigate the role of local adaptation in the diversification into subspecies and populations. We identified ~6 million high quality SNPs sampled at eight localities across the North Atlantic and adjacent waters, which we used for population structure, demographic and genotype-environment association analyses. Our results suggest a genetic differentiation between three subspecies (P.p. relicta, P.p. phocoena and P.p. meridionalis), and three distinct populations within P.p. phocoena: Atlantic, Belt Sea and Proper Baltic Sea. Effective population size and Tajima's D suggest population contraction in Black Sea and Iberian porpoises, but expansion in the P.p. phocoena populations. Phylogenetic trees indicate post-glacial colonization from a southern refugium. Genotype-environment association analysis identified salinity as major driver in genomic variation and we identified candidate genes putatively underlying adaptation to different salinity. Our study highlights the value of whole genome resequencing to unravel subtle population structure in highly mobile species, shows how strong environmental gradients and local adaptation may lead to population differentiation, and how neutral and adaptive markers can give different perspectives on population subdivision. The results have great conservation implications as we found inbreeding and low genetic diversity in the endangered Black Sea subspecies and identified the critically endangered Proper Baltic Sea porpoises as a separate population.

Effects of amplitude and duration of noise exposure on the hearing and anti-predator behaviour of common roach (Rutilus rutilus) and sand goby (Pomatoschistus minutus)

This study investigates whether an exposure to two different received sound pressure levels at equal cumulative energy affects anti-predator behaviour and auditory detection thresholds of common roach (Rutilus rutilus) and sand goby (Pomatoschistus minutus) differently. This was examined in regard to a vessel slowdown as a management strategy to decrease vessel noise impact on fishes. Using continuous broadband noise, we found significant temporary threshold shifts (TTS) in roach, with 11.9 and 13.4 dB at 250 and 1000 Hz respectively, for the louder exposure. In contrast, gobies exhibited a non-significant shift of 6.6 dB at 125 Hz. Group cohesion increased in roach exposed to an artificial predator in the control group, but not during noise exposures. Gobies showed an initial freezing reaction towards the predator stimulus remaining motionless regardless of treatment. Our results show that a reduction in vessel speed with a corresponding reduction in source level could mitigate the effects on the auditory senses of sensitive fish, but does not appear to have any mitigating effect on their noise-induced behavioural changes. Further studies should investigate the effects of multiple vessel passages, but also the ecological consequences of the described effects on hearing and behaviour at individual and population level.

Heartworms in Halichoerus grypus: first records of Acanthocheilonema spirocauda (Onchocercidae; Filarioidea) in 2 grey seals from the North Sea

The assumed definitive host of the heartworm Acanthocheilonema spirocauda (Onchocerdidae; Filarioidea) is the harbour seal (Phoca vitulina). This filaroid nematode parasitizing in cardiac ventricles and blood vessel lumina of harbour seals (P. vitulina) has a low prevalence and seldom causes severe health impacts. The seal louse (Echinophthirius horridus) is the assumed intermediate host for transmission of A. spirocauda filariae between seals, comprising a unique parasite assembly conveyed from the terrestrial ancestors of pinnipeds. Although grey seals (Halichoerus grypus) are infected by seal lice, heartworm infection was not verified. Analysing a longterm dataset compiled over decades (1996–2021) of health monitoring seals along the German coasts comprising post mortem investigations and archived parasites, 2 cases of A. spirocauda infected male grey seals were detected. Tentative morphological identification was confirmed with molecular tools by sequencing a section of mtDNA COI and comparing nucleotide data with available heartworm sequence. This is the first record of heartworm individuals collected from the heart of grey seals at necropsy. It remains puzzling why heartworm infection occur much less frequently in grey than in harbour seals, although both species use the same habitat, share mixed haul-outs and consume similar prey species. If transmission occurs directly via seal louse vectors on haul-outs, increasing seal populations in the North- and Baltic Sea could have density dependent effects on prevalence of heartworm and seal louse infections. It remains to be shown how species-specificity of filarial nematodes as well as immune system traits of grey seals influence infection patterns of A. spirocauda.

Differences in the internal PFAS patterns of herbivores, omnivores and carnivores - lessons learned from target screening and the total oxidizable precursor assay

Per- and polyfluorinated alkyl substances (PFAS) are a group of anthropogenic chemicals, which are not (fully) biodegradable and accumulate in different environmental compartments worldwide. A comprehensive, quantitative analysis - consisting of target analysis (66 different analytes, including e. g. ultrashort-chain perfluorinated carboxylic acids (PFCAs), precursor compounds and novel substitutes) and the Total Oxidisable Precursor (TOP) assay (including trifluoroacetic acid (TFA)) - were conducted to analyse the PFAS concentrations and patterns in 12 mammalian and two bird species from different areas of Germany and Denmark. The PFAS contamination was investigated in dependance of the trophic class (herbivores, omnivores, carnivores), ecological habitat (terrestrial, (semi-) aquatic) and body tissue (liver, musculature). PFAS concentrations were highest in carnivores, followed by omnivores and herbivores, with ∑PFAS concentration ranging from 1274 μg/kg (Eurasian otter liver) to 22 μg/kg (roe deer liver). TFA dominated in the herbivorous species, whereas perfluorooctanesulfonic acid (PFOS) and the long-chain PFCAs covered the majority of the PFAS contamination in carnivorous species. Besides trophic class, ecological habitat also affected the PFAS levels in the different species, with terrestrial herbivores and omnivores showing higher PFAS concentration than their aquatic counterparts, whereas for carnivores this relationship was reversed. The TOP assay analysis indicated similar trends, with the PFCA formation pattern differing significantly between the trophic classes. TFA was formed predominantly in herbivorous and omnivorous species, whereas in carnivorous species a broad spectrum of PFCAs (chain-length C2-C14) was formed. Musculature tissue of six species exhibited significantly lower PFAS concentrations than the respective liver tissue, but with similar PFAS patterns. The comprehensive approach applied in the present study showed, that primarily the trophic class is decisive for the PFAS concentration, as herbivores, omnivores and carnivores clearly differed in their PFAS concentrations and patterns. Additionally, the TOP assay gave novel insights in the PFCA formation potential in biota samples.

Comparative effectiveness of urine drug screening strategies alongside opioid agonist treatment in British Columbia, Canada: a population-based observational study protocol

INTRODUCTION

Urine drug tests (UDTs) are commonly used for monitoring opioid agonist treatment (OAT) responses, supporting the clinical decision for take-home doses and monitoring potential diversion. However, there is limited evidence supporting the utility of mandatory UDTs-particularly the impact of UDT frequency on OAT retention. Real-world evidence can inform patient-centred approaches to OAT and improve current strategies to address the ongoing opioid public health emergency. Our objective is to determine the safety and comparative effectiveness of alternative UDT monitoring strategies as observed in clinical practice among OAT clients in British Columbia, Canada from 2010 to 2020.

METHODS AND ANALYSIS

We propose a population-level retrospective cohort study of all individuals 18 years of age or older who initiated OAT from 1 January 2010 to 17 March 2020. The study will draw on eight linked health administrative databases from British Columbia. Our primary outcomes include OAT discontinuation and all-cause mortality. To determine the effectiveness of the intervention, we will emulate a 'per-protocol' target trial using a clone censoring approach to compare fixed and dynamic UDT monitoring strategies. A range of sensitivity analyses will be executed to determine the robustness of our results.

ETHICS AND DISSEMINATION

The protocol, cohort creation and analysis plan have been classified and approved as a quality improvement initiative by Providence Health Care Research Ethics Board and the Simon Fraser University Office of Research Ethics. Results will be disseminated to local advocacy groups and decision-makers, national and international clinical guideline developers, presented at international conferences and published in peer-reviewed journals electronically and in print.

Bone mineral density and microarchitecture change during skeletal growth in harbor seals (Phoca vitulina) from the German coast

Across species, the skeletal system shares mutual functions, including the protection of inner organs, structural basis for locomotion, and acting as an endocrine organ, thus being of pivotal importance for survival. However, insights into skeletal characteristics of marine mammals are limited, especially in the growing skeleton. Harbor seals (Phoca vitulina) are common marine mammals in the North and Baltic Seas and are suitable indicators of the condition of their ecosystem. Here, we analyzed whole-body areal bone mineral density (aBMD) by dual-energy X-ray absorptiometry (DXA) and lumbar vertebrae by high-resolution peripheral quantitative computed tomography (HR-pQCT) in neonate, juvenile, and adult harbor seals. Along skeletal growth, an increase in two-dimensional aBMD by DXA was paralleled by three-dimensional volumetric BMD by HR-pQCT, which could be attributed to an increasing trabecular thickness while trabecular number remained constant. Strong associations were observed between body dimensions (weight and length) and aBMD and trabecular microarchitecture (R² = 0.71-0.92, all p < 0.001). To validate the results of the DXA measurement (i.e., the standard method used worldwide to diagnose osteoporosis in humans), we performed linear regression analyses with the three-dimensional measurements from the HR-pQCT method, which revealed strong associations between the two imaging techniques (e.g., aBMD and Tb.Th: R² = 0.96, p < 0.0001). Taken together, our findings highlight the importance of systematic skeletal investigations in marine mammals during growth, illustrating the high accuracy of DXA in this context. Regardless of the limited sample size, the observed trabecular thickening is likely to represent a distinct pattern of vertebral bone maturation. As differences in nutritional status, among other factors, are likely to affect skeletal health, it appears essential to routinely perform skeletal assessments in marine mammals. Placing the results in the context of environmental exposures may allow effective measures to protect their populations.

Potential new species of pseudaliid lung nematode (Metastrongyloidea) from two stranded neonatal orcas (Orcinus orca) characterized by ITS-2 and COI sequences

Knowledge about parasite species of orcas, their prevalence, and impact on the health status is scarce. Only two records of lungworm infections in orca exist from male neonatal orcas stranded in Germany and Norway. The nematodes were identified as Halocercus sp. (Pseudaliidae), which have been described in the respiratory tract of multiple odontocete species, but morphological identification to species level remained impossible due to the fragile structure and ambiguous morphological features. Pseudaliid nematodes (Metastrongyloidea) are specific to the respiratory tract of toothed whales and are hypothesized to have become almost extinct in terrestrial mammals. Severe lungworm infections can cause secondary bacterial infections and bronchopneumonia and are a common cause of mortality in odontocetes. DNA isolations and subsequent sequencing of the rDNA ITS-2 and mtDNA COI revealed nucleotide differences between previously described Halocercus species from common dolphin (H. delphini) and harbor porpoises (H. invaginatus) that were comparatively analyzed, pointing toward a potentially new species of pseudaliid lungworm in orcas. New COI sequences of six additional metastrongyloid lungworms of seals and porpoises were derived to elucidate phylogenetic relationships and differences between nine species of Metastrongyloidea.

Movements and spatial usage of harbour seals in the Elbe estuary in Germany

Harbour seals are top predators in the North Sea and regarded as sentinels for ecosystem health. A few hundred also occur in adjacent estuaries, such as the Elbe estuary, Germany. However, only little is known about how these animals use this dynamic tidally influenced habitat, which has been under high anthropogenic pressure for decades. In this context, nine harbour seals (Phoca vitulina) from the Elbe estuary were equipped with biotelemetry devices to track their movements over multiple months. Harbour seal movements were characterised by short trips (trip length outside pupping season for females: 9.0 ± 1.12 km, males: 7.0 ± 1.24 km) as well as small home ranges (median 50% home range for females: 16.3 km², males: 36.1 km²) compared to harbour seals from marine regions. Within the estuary, the animals utilised the fairway, river branches and tributaries. During the pupping season in June and July, four seals showed strongly reduced trip lengths and durations, increased daily haul out durations as well as smaller home ranges. Even though a continuous exchange with harbour seals from the Wadden Sea likely occurs, most individuals in this study spent the entire deployment duration inside the estuary. This indicates that the Elbe estuary provides a suitable habitat for harbour seals, despite extensive anthropogenic usage, calling for further studies on the consequences of living in such an industrialised habitat.

Vessel noise exposures of harbour seals from the Wadden Sea

The North Sea faces intense ship traffic owing to increasing human activities at sea. As harbour seals (Phoca vitulina) are abundant top predators in the North Sea, it is hypothesised that they experience repeated, high-amplitude vessel exposures. Here, we test this hypothesis by quantifying vessel noise exposures from deployments of long-term sound and movement tags (DTAGs) on nine harbour seals from the Wadden Sea. An automated tool was developed to detect intervals of elevated noise in the sound recordings. An assessment by multiple raters was performed to classify the source as either vessels or other sounds. A total of 133 vessel passes were identified with received levels > 97 dB re 1µPa RMS in the 2 kHz decidecade band and with ambient noise > 6 dB below this detection threshold. Tagged seals spent most of their time within Marine Protected Areas (89 ± 13%, mean ± SD) and were exposed to high-amplitude vessel passes 4.3 ± 1.6 times per day. Only 32% of vessel passes were plausibly associated with an AIS-registered vessel. We conclude that seals in industrialized waters are exposed repeatedly to vessel noise, even in areas designated as protected, and that exposures are poorly predicted by AIS data.

Back from Exile? First Records of Chewing Lice (Lutridia exilis; Ischnocera; Mallophaga) in Growing Eurasian Otter (Lutra lutra) Populations from Northern Germany

Arthropod ectoparasites of aquatic wildlife often have complex relationships with their host species that have developed over long evolutionary time scales. Specialist parasite occurrence might depend on these hosts' distributions. Eurasian otter (Lutra lutra) populations are recovering in Northern German federal states, such as Schleswig-Holstein and Lower Saxony. Chewing lice (Lutridia exilis; Ischnocera; Mallophaga) are considered otter-specific yet rare parasites in their known range. In 2022, they were recorded for the first time on nine otters found dead in Northern Germany. All otters originated from the years 2021-2022 and were dissected during population health monitoring programs in 2022. Females (n = 6) were 0-5.5 years old and showed signs of disease in five cases. Males (n = 3), in contrast, were 0-1.6 years old and showed disease in a single case. Individual lice intensity of infection ranged from 1 to 75 specimens per otter. No direct adverse health effects of chewing lice on the otters were noted. Lutridia exilis morphological characteristics were documented and measurements were taken to study specialized adaptations that allow lice to attach to semi-aquatic otters. In addition, morphology was compared between lice from different geographical regions and specimens from previous reports. A region of the COI mDNA was amplified to molecularly characterize L. exilis for the first time and detect genetic differences between otter lice populations in Germany. It is believed that specialist parasites reduce in numbers even before their host populations decline. Recovering otter populations in Northern Germany could be an example of a reverse effect, where the comeback of a host species results in the return of a specialist parasite, which reflects an ultimate boost in overall species biodiversity.

Present in the Aquatic Environment, Unclear Evidence in Top Predators-The Unknown Effects of Anti-Seizure Medication on Eurasian Otters (Lutra lutra) from Northern Germany

Emerging contaminants are produced globally at high rates and often ultimately find their way into the aquatic environment. These include substances contained in anti-seizure medication (ASM), which are currently appearing in surface waters at increasing concentrations in Germany. Unintentional and sublethal, chronic exposure to pharmaceuticals such as ASMs has unknown consequences for aquatic wildlife. Adverse effects of ASMs on the brain development are documented in mammals. Top predators such as Eurasian otters (Lutra lutra) are susceptible to the bioaccumulation of environmental pollutants. Still little is known about the health status of the otter population in Germany, while the detection of various pollutants in otter tissue samples has highlighted their role as an indicator species. To investigate potential contamination with pharmaceuticals, Eurasian otter brain samples were screened for selected ASMs via high-performance liquid chromatography and mass spectrometry. Via histology, brain sections were analyzed for the presence of potential associated neuropathological changes. In addition to 20 wild otters that were found dead, a control group of 5 deceased otters in human care was studied. Even though none of the targeted ASMs were detected in the otters, unidentified substances in many otter brains were measured. No obvious pathology was observed histologically, although the sample quality limited the investigations.

Toothed whales use distinct vocal registers for echolocation and communication

Echolocating toothed whales (odontocetes) capture fast-moving prey in dark marine environments, which critically depends on their ability to generate powerful, ultrasonic clicks. How their supposedly air-driven sound source can produce biosonar clicks at depths of >1000 meters, while also producing rich vocal repertoires to mediate complex social communication, remains unknown. We show that odontocetes possess a sound production system based on air driven through nasal passages that is functionally analogous to laryngeal and syringeal sound production. Tissue vibration in different registers produces distinct echolocation and communication signals across all major odontocete clades, and thus provides a physiological basis for classifying their vocal repertoires. The vocal fry register is used by species from porpoises to sperm whales for generating powerful, highly air-efficient echolocation clicks.

Heavy Youngsters-Habitat and Climate Factors Lead to a Significant Increase in Body Weight of Wild Boar Females

As one of the most abundant game species in Europe, European wild boar (Sus scrofa) populations prove highly adaptable to cultivated landscapes. The ongoing process of climate change and the high agricultural yields seem to further optimize the living conditions for this species. In long-term reproduction monitoring, we collected data on the body weight of wild boar females. Over an 18-year period, the body weight of wild boar females increased continuously, then stopped and decreased. It was possible to detect differences between the body weights of animals from forest and agricultural areas. For these areas, differences in body weight development also led to a significant distinction in the onset of puberty. We conclude that, even in a highly cultivated landscape, forested areas provide habitat characteristics that may strongly influence reproduction. Second, with dominant agricultural areas in Germany, wild boar reproduction has been favored in recent decades.

Elements in muscle tissue of three dolphin species from the east coast of South Africa

We investigated elemental concentrations in muscle tissue of three species of dolphins incidentally bycaught off the KwaZulu-Natal coastline, South Africa. Thirty-six major, minor and trace elements were analysed in Indian Ocean humpback dolphin Sousa plumbea (n = 36), Indo-Pacific bottlenose dolphin Tursiops aduncus (n = 32) and the Common dolphin Delphinus delphis (n = 8). Significant differences in concentration between the three species were observed for 11 elements (cadmium, iron, manganese, sodium, platinum, antimony, selenium, strontium, uranium, vanadium and zinc). Mercury concentrations (maximum 29 mg/kg dry mass) were generally higher than those reported for coastal dolphin species found elsewhere. Our results reflect a combination of species differences in habitat, feeding ecology, age, and possibly species physiology and exposure to pollution levels. This study confirms the high organic pollutant concentrations documented previously for these species from the same location, and provides a well-founded case for the need to reduce pollutant sources.

Cardio-pulmonary parasites of the European wildcat (Felis silvestris) in Germany

BACKGROUND

In the last years, research on feline cardio-pulmonary parasites has considerably increased in Europe. Not only domestic cats (Felis catus), but also European wildcats (Felis silvestris) can serve as definitive hosts for these nematodes. The F. silvestris population in Germany has been growing rapidly within the last decades; therefore, the assessment of its cardio-pulmonary parasite status is of importance to unravel whether the wildcat population serves as a substantial reservoir for these nematodes and might pose a health threat to domestic cats.

METHODS

As part of a nature conservation project for European wildcats in the German federal state Rhineland-Palatinate, lungs (n = 128) and hearts (n = 111) of 128 F. silvestris found dead were examined for cardio-pulmonary parasites. All isolated parasites were identified morphologically, and results were confirmed by molecular analysis of a total of 3-11 specimens of each worm species.

RESULTS

A total of 70.3% (90/128) wildcats were positive for at least one lungworm species. Angiostrongylus chabaudi was most common (53.1% [68/128]), followed by Aelurostrongylus abstrusus (42.2% [54/128]), Troglostrongylus brevior (31.3% [40/128]) and Capillaria spp. (3.1% [4/128]). Of note, about two-thirds of the infected wildcats harboured coinfections. Infection intensities ranged from 1 to 167 nematodes per wildcat. Generalised linear models revealed a strong correlation between A. chabaudi and A. abstrusus infection, and prevalences were higher in adult than in younger wildcats, except for T. brevior. Moreover, the T. brevior prevalence varied significantly with nutritional status.

CONCLUSIONS

This study shows that feline cardio-pulmonary nematodes are common parasites in European wildcats in Germany but do not appear to have a serious impact on the overall health of the population. Due to presumed spillover events via prey, cardio-pulmonary nematodes may circulate between the wildcat population and domestic cats and might therefore pose a health risk to individual domestic cats.

Assessment of contaminants of emerging concern in European apex predators and their prey by LC-QToF MS wide-scope target analysis

Apex predators are good indicators of environmental pollution since they are relatively long-lived and their high trophic position and spatiotemporal exposure to chemicals provides insights into the persistent, bioaccumulative and toxic (PBT) properties of chemicals. Although monitoring data from apex predators can considerably support chemicals' management, there is a lack of pan-European studies, and longer-term monitoring of chemicals in organisms from higher trophic levels. The present study investigated the occurrence of contaminants of emerging concern (CECs) in 67 freshwater, marine and terrestrial apex predators and in freshwater and marine prey, gathered from four European countries. Generic sample preparation protocols for the extraction of CECs with a broad range of physicochemical properties and the purification of the extracts were used. The analysis was performed utilizing liquid (LC) chromatography coupled to high resolution mass spectrometry (HRMS), while the acquired chromatograms were screened for the presence of more than 2,200 CECs through wide-scope target analysis. In total, 145 CECs were determined in the apex predator and their prey samples belonging in different categories, such as pharmaceuticals, plant protection products, per- and polyfluoroalkyl substances, their metabolites and transformation products. Higher concentration levels were measured in predators compared to prey, suggesting that biomagnification of chemicals through the food chain occurs. The compounds were prioritized for further regulatory risk assessment based on their frequency of detection and their concentration levels. The majority of the prioritized CECs were lipophilic, although the presence of more polar contaminants should not be neglected. This indicates that holistic analytical approaches are required to fully characterize the chemical universe of biota samples. Therefore, the present survey is an attempt to systematically investigate the presence of thousands of chemicals at a European level, aiming to use these data for better chemicals management and contribute to EU Zero Pollution Ambition.

Variation of blubber thickness for three marine mammal species in the southern Baltic Sea

Evaluating populational trends of health condition has become an important topic for marine mammal populations under the Marine Strategy Framework Directive (MSFD). In the Baltic Sea, under the recommendation of Helsinki Commission (HELCOM), efforts have been undertaken to use blubber thickness as an indicator of energy reserves in marine mammals. Current values lack geographical representation from the entire Baltic Sea area and a large dataset is only available for grey seals (Halichoerus grypus) from Sweden and Finland. Knowledge on variation of blubber thickness related to geography throughout the Baltic Sea is important for its usage as an indicator. Such evaluation can provide important information about the energy reserves, and hence, food availability. It is expected that methodological standardization under HELCOM should include relevant datasets with good geographical coverage that can also account for natural variability in the resident marine mammal populations. In this study, seasonal and temporal trends of blubber thickness were evaluated for three marine mammal species-harbor seal (Phoca vitulina), grey seal (Halichoerus grypus) and harbor porpoise (Phocoena phocoena)-resident in the southern Baltic Sea collected and investigated under stranding networks. Additionally, the effects of age, season and sex were analyzed. Seasonal variation of blubber thickness was evident for all species, with harbor seals presenting more pronounced effects in adults and grey seals and harbor porpoises presenting more pronounced effects in juveniles. For harbor seals and porpoises, fluctuations were present over the years included in the analysis. In the seal species, blubber thickness values were generally higher in males. In harbor seals and porpoises, blubber thickness values differed between the age classes: while adult harbor seals displayed thicker blubber layers than juveniles, the opposite was observed for harbor porpoises. Furthermore, while an important initial screening tool, blubber thickness assessment cannot be considered a valid methodology for overall health assessment in marine mammals and should be complemented with data on specific health parameters developed for each species.

Energetic Compounds in the Trophic Chain—A Pilot Study Examining the Exposure Risk of Common Eiders (Somateria mollissima) to TNT, Its Metabolites, and By-Products

The Baltic and North Seas still contain large amounts of dumped munitions from both World Wars. The exposure of the munition shells to the seawater causes corrosion, which leads to the disintegration of shells and a leakage of energetic compounds, including the highly toxic 2,4,6-trinitrotoluene (TNT), and consequently threatening the marine environment. To evaluate the risk of accumulation of energetic compounds from conventional munitions in the marine food chain, we analyzed the presence of TNT and its metabolites 2-amino-4,6-dinitrotoluene (2-ADNT) and 4-amino-2,6-dinitrotoluene (4-ADNT) as well as their byproducts 1,3-dinitrobenzene (1,3-DNB) and 2,4-dinitrotoluene (2,4-DNT) in different tissues (including muscle, liver, kidney, brain, and bile) from 25 Common Eiders (Somateria mollissima) from the Danish Baltic Sea. Tissues were prepared according to approved protocols, followed by GC-MS/MS analysis. None of the aforementioned energetic compounds were detected in any of the samples. This pilot study is one of the first analyzing the presence of explosive chemicals in tissues from a free-ranging predatory species. This study highlights the need for continuous monitoring at different levels of the trophic chain to increase our knowledge on the distribution and possible accumulation of energetic compounds in the marine environment in order to provide reliable data for decision-making tools and risk assessments.

Arcanobacterium buesumense sp. nov., isolated from an anal swab of a male harbour seal (Phoca vitulina)

A polyphasic taxonomic study was performed on an unidentified previously described Arcanobacterium -like Gram-positive strain 2701T isolated from an anal swab of a dead male harbour seal. Comparative 16S rRNA sequencing showed that the bacterium belonged to the genus Arcanobacterium in the family Arcanobacteriaceae . The genome sequence of the strain was obtained by Borowiak et al. []. The genome had a G+C content of 49 mol% and a total length of 1.94 Mb. The presence of the major menaquinone MK-9(H4) supported the affiliation of the isolate with the genus Arcanobacterium . The polar lipid profile consisted of diphosphatidylglycerol and an unidentified phospholipid as major components and two unidentified lipids, a further unidentified phospholipid, two unidentified phosphoglycolipids as well as phosphatidylglycerol. The major fatty acids were C16 : 0, C18 : 1 and C18 : 0. Biochemical and phylogenetic analyses clearly distinguished the isolate from other members of the genus Arcanobacterium and closely related other species. Based on these results, it is proposed that the unknown Arcanobacterium sp. strain 2701T should be classified as representing a novel species with the name Arcanobacterium buesumense sp. nov. The type strain is 2701T (=DSM 112952T=LMG 32446T).

Habitat selection of black grouse in an isolated population in northern Germany-the importance of mixing dry and wet habitats

Wildlife habitats in general must provide foraging, hiding and resting places as well as sites for reproduction. Little is known about habitat selection of black grouse in the lowlands of Central Europe. We investigated habitat selection of seven radio tagged birds in an open heath and grassland area surrounded by dense pine forests in the northern German Lüneburg Heath Nature Reserve. This site carries one of the last remaining populations in the Central European lowlands. Using resource selection functions based on presence/background data, we estimated the probability of black grouse occurrence by availability of, or distance to habitat types as well as vegetation diversity indices. Black grouse preferred undisturbed and heterogeneous habitats far from dense forests with wide sand heaths, natural grasslands and intermixed bogs, diverse vegetation and food sources, low density of (loose) shrub formations and solitary trees. Wetlands were extremely important in a landscape that is dominated by dry heaths and grasslands. About 4% (9 km²) of the nature reserve was a suitable habitat for black grouse, mostly due to lack of open areas due to the amount of dense forest, and because smaller, open heaths are only partly suitable. We suggest that to improve habitat quality and quantity for the grouse, habitat patch size and connectivity must be increased, along with a mosaic of heterogeneous landscape structures in these habitat islands. Our results may be used to inform and improve black grouse habitat management in the region and elsewhere.

Occurrence of Antimicrobial-Resistant Escherichia coli in Marine Mammals of the North and Baltic Seas: Sentinels for Human Health

Antimicrobial resistance is a global health threat that involves complex, opaque transmission processes in the environment. In particular, wildlife appears to function as a reservoir and vector for antimicrobial-resistant bacteria as well as resistance genes. In the present study, the occurrence of antimicrobial-resistant Escherichia coli was determined in marine mammals and various fish species of the North and Baltic Seas. Rectal or faecal swabs were collected from 66 live-caught or stranded marine mammals and 40 fish specimens. The antimicrobial resistance phenotypes and genotypes of isolated E. coli were determined using disk diffusion tests and PCR assays. Furthermore, isolates were assigned to the four major phylogenetic groups of E. coli. Additionally, post mortem examinations were performed on 41 of the sampled marine mammals. The investigations revealed resistant E. coli in 39.4% of the marine mammal samples, while no resistant isolates were obtained from any of the fish samples. The obtained isolates most frequently exhibited resistance against aminoglycosides, followed by β-lactams. Of the isolates, 37.2% showed multidrug resistance. Harbour porpoises (Phocoena phocoena) mainly carried E. coli isolates belonging to the phylogenetic group B1, while seal isolates were most frequently assigned to group B2. Regarding antimicrobial resistance, no significant differences were seen between the two sampling areas or different health parameters, but multidrug-resistant isolates were more frequent in harbour porpoises than in the sampled seals. The presented results provide information on the distribution of antimicrobial-resistant bacteria in the North and Baltic Seas, and highlight the role of these resident marine mammal species as sentinels from a One Health perspective.

Health Status of Bycaught Common Eiders (Somateria mollissima) from the Western Baltic Sea

Simple Summary

We performed post-mortem investigations of 121 Common Eiders (Somateria mollissima), which were incidentally caught in fishing gear from 2017 to 2019 in Denmark. The aim of the study was to obtain an overview of health issues and pathogens occurring in the population of these birds. The European population of the Common Eider is endangered, but the reasons for the decline of the population have not yet been determined. In times of accelerating species loss, it is important to determine factors that impact population numbers of declining species. The post-mortem investigations included biometric measurements and determination of age, sex and nutritional status, as well as parasitological, bacteriological and virological investigations. The majority of Common Eiders had a good or moderate nutritional status. Most animals were infected with intestinal parasites, and we commonly found inflammation in organs like the liver, kidneys, intestine and the oesophagus. In three animals, a pathogenic bacterium caused inflammatory lesions in several organs. We did not find signs for epizootic diseases or pathologies, which would explain the declining species numbers.

Abstract

The Common Eider (Somateria mollissima) inhabits the entire northern hemisphere. In northern Europe, the flyway population reaches from the southern Wadden Sea to the northern Baltic coast. The European population is classified as endangered due to declines in Common Eider numbers across Europe since 1990. In this study, we assessed 121 carcasses of Common Eiders, captured incidentally in gillnets in the Western Baltic between 2017 and 2019. The most common findings were parasitic infections of the intestine by acanthocephalans in 95 animals, which correlated with enteritis in 50% of the cases. Parasites were identified as Profilicollis botulus in 25 selected animals. Additionally, oesophageal pustules, erosions, and ulcerations, presumably of traumatic origin, were frequently observed. Nephritis and hepatitis were frequent, but could not be attributed to specific causes. Lung oedema, fractures and subcutaneous haemorrhages likely resulted from entangling and drowning. Two Common Eiders had mycobacterial infections and in one of these, Mycobacterium avium subspecies (ssp.) avium was identified. This study gives an overview of morphological changes and infectious diseases from one location of the European flyway population. It contributes to future health studies on Common Eiders in the Baltic and Wadden Seas by providing baseline information to compare with other areas or circumstances.

3D Visualization Processes for Recreating and Studying Organismal Form

The study of biological form is a vital goal of evolutionary biology and functional morphology. We review an emerging set of methods that allow scientists to create and study accurate 3D models of living organisms and animate those models for biomechanical and fluid dynamic analyses. The methods for creating such models include 3D photogrammetry, laser and CT scanning, and 3D software. New multi-camera devices can be used to create accurate 3D models of living animals in the wild and captivity. New websites and virtual reality/augmented reality devices now enable the visualization and sharing of these data. We provide examples of these approaches for animals ranging from large whales to lizards and show applications for several areas: Natural history collections; body condition/scaling, bioinspired robotics, computational fluids dynamics (CFD), machine learning, and education. We provide two datasets to demonstrate the efficacy of CFD and machine learning approaches and conclude with a prospectus.

A risk assessment review of mercury exposure in Arctic marine and terrestrial mammals

There has been a considerable number of reports on Hg concentrations in Arctic mammals since the last Arctic Monitoring and Assessment Programme (AMAP) effort to review biological effects of the exposure to mercury (Hg) in Arctic biota in 2010 and 2018. Here, we provide an update on the state of the knowledge of health risk associated with Hg concentrations in Arctic marine and terrestrial mammal species. Using available population-specific data post-2000, our ultimate goal is to provide an updated evidence-based estimate of the risk for adverse health effects from Hg exposure in Arctic mammal species at the individual and population level. Tissue residues of Hg in 13 species across the Arctic were classified into five risk categories (from No risk to Severe risk) based on critical tissue concentrations derived from experimental studies on harp seals and mink. Exposure to Hg lead to low or no risk for health effects in most populations of marine and terrestrial mammals, however, subpopulations of polar bears, pilot whales, narwhals, beluga and hooded seals are highly exposed in geographic hotspots raising concern for Hg-induced toxicological effects. About 6% of a total of 3500 individuals, across different marine mammal species, age groups and regions, are at high or severe risk of health effects from Hg exposure. The corresponding figure for the 12 terrestrial species, regions and age groups was as low as 0.3% of a total of 731 individuals analyzed for their Hg loads. Temporal analyses indicated that the proportion of polar bears at low or moderate risk has increased in East/West Greenland and Western Hudson Bay, respectively. However, there remain numerous knowledge gaps to improve risk assessments of Hg exposure in Arctic mammalian species, including the establishment of improved concentration thresholds and upscaling to the assessment of population-level effects.

Activation of the xenobiotic metabolism and oxidative stress response by mixtures of organic pollutants extracted with in-tissue passive sampling from liver, kidney, brain and blubber of marine mammals

We used in-tissue passive equilibrium sampling using the silicone polydimethylsiloxane (PDMS) to transfer chemical mixtures present in organs from marine mammals with lipid contents between 2.3 and 99%into in vitro bioassays. Tissues from five harbor porpoises (Phocoena phocoena), one harbor seal (Phoca vitulina) and one orca (Orcinus orca) from the North and Baltic Seas were sampled until thermodynamic equilibrium was reached. Mixture effects were quantified with cellular reporter gene bioassays targeting the activation of the aryl hydrocarbon receptor (AhR-CALUX), the peroxisome proliferator-activated receptor gamma (PPARγ-bla) and the oxidative stress response (AREc32), with parallel cytotoxicity measurements in all assays. After removing co-extracted lipids and other matrix residues with a non-destructive cleanup method (freeze-out of acetonitrile extract followed by a primary secondary amine sorbent extraction), the activation of the PPARγ and AREc32 were reduced by factors of on average 4.3 ± 0.15 (n = 22) and 2.5 ± 0.23 (n = 18), respectively, whereas the activation of the AhR remained largely unaltered: 1.1 ± 0.075 (n = 6). The liver extracts showed the highest activation, followed by the corresponding kidney and brain extracts, and the blubber extracts of the animals were the least active ones. The activation of the PPARγ by the liver extracts was reduced after cleanup by a factor of 11 ± 0.26 (n = 7) and the AREc32 activity by a factor of 1.9 ± 0.32 (n = 4). The blubber extracts did not activate the AhR up to concentrations where cytotoxicity occurred or up to an acceptable lipid volume fraction of 0.27% as derived from earlier work, whereas all liver extracts that had undergone cleanup activated the AhR. The developed in-tissue passive sampling approach allows a direct comparison of the bioassay responses between different tissues without further normalization and serves as a quantitative method suitable for biomonitoring of environmental biota samples.

Spontaneous neoplasms in harbour porpoises Phocoena phocoena

Harbour porpoises are widely distributed in the North Atlantic and represent the most abundant cetacean species in the North and Baltic Seas. Spontaneous neoplasms are relatively rarely reported in cetaceans, and only little is known about neoplasia in harbour porpoises. Thus, archival material was reviewed for spontaneous neoplasms in harbour porpoises recorded during post-mortem examinations between 1999 and 2018. Neoplasms were identified in 7 adult porpoises: 6 animals originating from the North and Baltic Seas and investigated as part of German and Dutch systematic health monitoring programs, and 1 porpoise from Greenlandic waters. The tumours were of different histogenetic origins and further characterised by histology and immunohistochemistry. One individual had a neoplasia in the digestive tract (adenocarcinoma, n = 1); 4 animals, in the genital tract (Sertoli cell tumour, n = 1; genital leiomyoma/fibroleiomyoma, n = 3); and 2 porpoises, in endocrine organs (adrenal adenoma, n = 2). This is the first report of an adenocarcinoma in the liver, a testicular Sertoli cell tumour and adrenocortical adenomas in harbour porpoises. The cause of the tumorigenesis in examined cases remains undetermined. The involvement of endogenous factors, including mutation of cell cycle regulating genes, such as the tumour-suppressor gene p53, cannot be ruled out. The aetiopathogenetic significance of exogenous factors, such as infectious agents like liver flukes or anthropogenic factors, including persistent organic pollutants, should be the subject of future investigations.

Primary harbor seal (Phoca vitulina) airway epithelial cells show high susceptibility to infection by a seal-derived influenza A virus (H5N8)

Highly pathogenic avian influenza viruses of the H5N8 subtype have been circulating in Europe and Asia since 2016, causing huge economic losses to the poultry industry. A new wave of H5Nx infections has begun in 2020. The viruses mainly infect wild birds and waterfowl; from there they spread to poultry and cause disease. Previous studies have shown that the H5N8 viruses have seldom spread to mammals; however, reports in early 2021 indicate that humans may be infected, and some incident reports indicate that H5Nx clade 2.3.4.4B virus may be transmitted to wild mammals, such as red foxes and seals. In order to get more information on how the H5N8 virus affects seals and other marine animals, here, we used primary cultures to analyze the cell tropism of the H5N8 virus, which was isolated from an infected gray seal (H5N8/Seal-2016). Primary tracheal epithelial cells were readily infected by H5N8/Seal -2016 virus; in contrast, the commonly used primary seal kidney cells required the presence of exogenous trypsin to initiate virus infection. When applied to an ex vivo precision-cut lung slice model, compared with recombinant human H3N2 virus or H9N2 LPAI virus, the H5N8/Seal-2016 virus replicated to a high titer and caused a strong detrimental effect; with these characteristics, the virus was superior to a human H3N2 virus and to an H9N2 LPAI virus. By using well-differentiated air-liquid interface cultures, we have observed that ALI cultures of canines, ferrets, and harbor seals are more sensitive to H5N8/Seal-2016 virus than are human or porcine ALI cultures, which cannot be fully explained by sialic acid distribution. Our results indicate that the airway epithelium of carnivores may be the main target of H5N8 viruses. Consideration should be given to an increased monitoring of the distribution of highly pathogenic avian influenza viruses in wild animals. This article is protected by copyright. All rights reserved.

Number of Primordial Follicles in Juvenile Ringed Seals (Pusa hispida) from the Gulf of Bothnia and West Greenland

Primordial follicles are important for the reproduction cycle and, therefore, also for the survival of the whole population of a species. Mammals have a large pool of primordial follicles, and it is thought that this pool represents the total number of oocytes. The aim of the present study was to determine the total primordial follicle number of juvenile ringed seals (Pusa hispida) from the Gulf of Bothnia and Greenland. Overall, 52 ovaries from two ringed seal populations (West Greenland (N = 6), Gulf of Bothnia, region in the Baltic Sea (N = 46)) were examined. All ovaries were cut into 2 mm thick slices and every slice was embedded in paraffin. Out of each tissue block, a 5 µm thick section was cut and stained with haematoxylin-eosin. The mean volume of the follicles and the total volume of primordial follicles per ovary were estimated by stereology and used to calculate the total estimated number of primordial follicles. The median of the total estimated number of primordial follicles seemed to be higher in Baltic individuals than in Greenland individuals (Gulf of Bothnia = 565,657; Greenland Sea = 122,475). This widens the total range of primordial follicles in ringed seals overall and might bear some potential for discussions regarding the influence of endocrine disruptors and environmental influences depending on different regions/populations and their exposure to various factors. Thus, this study aims to provide basic reference data of the number and mean volume of ringed seal primordial follicles.

Occurrence of Microplastics in Harbour Seals (Phoca vitulina) and Grey Seals (Halichoerus grypus) from German Waters

The level of knowledge on microplastic exposure in marine mammals is limited by the access to dead and alive individuals. Focusing on the Northeast Atlantic area, some studies already confirmed the microplastic presence in free-ranging marine mammals, such as harbour porpoises or harbour seals inhabiting the North Sea (NS). In contrast, knowledge on the exposure to grey seals and particularly on specimen inhabiting the Baltic Sea (BS) are scarce. This study examined 63 gastrointestinal tracts (GIT) of harbour seals and grey seals originating from German waters (NS and BS) found between 2014 and 2019. Besides the documentation of microplastic findings, this study is dealing with life history and health parameters, attempting to identify correlations with microplastic presence. This study confirmed beside the presence, the egestion of microplastics (>100 µm; MPs) in the examined seals, without correlations in parasite infestations or inflammation responses. 540 suspected MPs were identified in 62 intestinal samples (42% fibres, 58% fragments), and 228 MPs in seven stomachs (28% fibres, 72% fragments). In accordance, first evidence of the retainment of fragments in the GIT were given. However, no significant difference in MP occurrence was indicated for different sex or age groups.

Infections with highly pathogenic avian influenza A virus (HPAIV) H5N8 in harbor seals at the German North Sea coast, 2021

In brain tissue of three harbor seals of the German North Sea coast, high virus loads of highly pathogenic avian influenza virus (HPAIV) H5N8 were detected. Identification of different virus variants indicates high exposure to HPAIV circulating in wild birds, but there is no evidence for H5 specific antibodies in healthy seals. Replication of avian viruses in seals may allow HPAIV to acquire mutations needed to adapt to mammalian hosts as shown by PB2 627K variants detected in these cases.

In the Search of Marine Pestiviruses: First Case of Phocoena Pestivirus in a Belt Sea Harbour Porpoise

Pestiviruses are widespread pathogens causing severe acute and chronic diseases among terrestrial mammals. Recently, Phocoena pestivirus (PhoPeV) was described in harbour porpoises (Phocoena phocoena) of the North Sea, expanding the host range to marine mammals. While the role of the virus is unknown, intrauterine infections with the most closely related pestiviruses— Bungowannah pestivirus (BuPV) and Linda virus (LindaV)—can cause increased rates of abortions and deaths in young piglets. Such diseases could severely impact already vulnerable harbour porpoise populations. Here, we investigated the presence of PhoPeV in 77 harbour porpoises, 277 harbour seals (Phoca vitulina), grey seals (Halichoerus grypus) and ringed seals (Pusa hispida) collected in the Baltic Sea region between 2002 and 2019. The full genome sequence of a pestivirus was obtained from a juvenile female porpoise collected along the coast of Zealand in Denmark in 2011. The comparative Bayesian phylogenetic analyses revealed a close relationship between the new PhoPeV sequence and previously published North Sea sequences with a recent divergence from genotype 1 sequences between 2005 and 2009. Our findings provide further insight into the circulation of PhoPeV and expand the distribution from the North Sea to the Baltic Sea region with possible implications for the vulnerable Belt Sea and endangered Baltic Proper harbour porpoise populations.

Blast injury on harbour porpoises (Phocoena phocoena) from the Baltic Sea after explosions of deposits of World War II ammunition

Harbour porpoises are under pressure from increasing human activities. This includes the detonation of ammunition that was dumped in large amounts into the sea during and after World War II. In this context, forty-two British ground mines from World War II were cleared by means of blasting in the period from 28 to 31 August 2019 by a NATO unit in the German Exclusive Economic Zone within the marine protected area of Fehmarn Belt in the Baltic Sea, Germany. Between September and November 2019, 24 harbour porpoises were found dead in the period after those clearing events along the coastline of the federal state of Schleswig-Holstein and were investigated for direct and indirect effects of blast injury. Health evaluations were conducted including examinations of the brain, the air-filled (lungs and gastrointestinal tract) and acoustic organs (melon, acoustic fat in the lower jaw, ears and their surrounding tissues). The bone structure of the tympano-periotic complexes was examined using high-resolution peripheral quantitative computed tomography (HR-pQCT). In 8/24 harbour porpoises, microfractures of the malleus, dislocation of middle ear bones, bleeding, and haemorrhages in the melon, lower jaw and peribullar acoustic fat were detected, suggesting blast injury. In addition, one bycaught animal and another porpoise with signs of blunt force trauma also showed evidence of blast injury. The cause of death of the other 14 animals varied and remained unclear in two individuals. Due to the vulnerability and the conservation status of harbour porpoise populations in the Baltic Sea, noise mitigation measures must be improved to prevent any risk of injury. The data presented here highlight the importance of systematic investigations into the acute and chronic effects of blast and acoustic trauma in harbour porpoises, improving the understanding of underwater noise effects and herewith develop effective measures to protect the population level.