Eurasian otters prefer to prey on religious released non-native fish on the Qinghai-Tibetan Plateau.

Religious wildlife release is prevalent worldwide, especially in Asia countries. It is one of the anthropogenic pathways to cause biological invasions. Religious fish release is common on the Qinghai-Tibetan Plateau, yet few studies have assessed the influences of religious fish release on local species. In Yushu, a city on the Qinghai-Tibetan Plateau, we interviewed local people, conducted fish trap surveys in local rivers, and examined the diet of Eurasian otters Lutra lutra using a fecal DNA metabarcoding approach. We found that fish release started at least in 1980-1990s in Yushu. Tibetan residents released fish in large amounts and released fish were usually exotic commercial fish purchased from market. Despite such long-term and intensive fish release activities, released fish were few in local rivers. On the other hand, Eurasian otters mainly prey on fish and released fish accounted for ~20% of relative read abundance of prey DNA in otters' diet, indicating their high preference on released fish. Our study suggested that religious fish release may provide additional food resources for otters, whereas otters, as a top predator in local rivers, may deplete non-native fish once they were released and, therefore, reduce the probability of colonization of released fish, although further studies are required to assess otters' impact. Our study revealed otters' diet in Yushu, providing basic information for local otter management and conservation. Furthermore, it represents a case showing that native predators prey on religious released animals, implying a probable direction for controlling invasive species through native predator conservation.

Persistence of PFOA Pollution at a PTFE Production Site and Occurrence of Replacement PFASs in English Freshwaters Revealed by Sentinel Species, the Eurasian Otter (Lutra lutra).

Concentrations of 33 PFASs were determined in 20 Eurasian otters, sampled 2015-2019, along a transect away from a factory, which used PFOA in PTFE manufacture. Despite cessation of usage in 2012, PFOA concentrations remained high near the factory (>298 µg/kg ww <20 km from factory) and declined with increasing distance (<57 µg/kg ww >150 km away). Long-chain legacy PFASs dominated the Σ33PFAS profile, particularly PFOS, PFOA, PFDA, and PFNA. Replacement compounds, PFECHS, F-53B, PFBSA, PFBS, PFHpA, and 8:2 FTS, were detected in ≥19 otters, this being the first report of PFBSA and PFECHS in the species. Concentrations of replacement PFASs were generally lower than legacy compounds (max: 70.3 µg/kg ww and 4,640 µg/kg ww, respectively). Our study underscores the utility of otters as sentinels for evaluating mitigation success and highlights the value of continued monitoring to provide insights into the longevity of spatial associations with historic sources. Lower concentrations of replacement, than legacy, PFASs likely reflect their lower bioaccumulation potential, and more recent introduction. Continued PFAS use will inevitably lead to increased environmental and human exposure if not controlled. Further research is needed on fate, toxicity, and bioaccumulation of replacement compounds.

Study of Canine Distemper Virus Presence in Catalonia's Wild Carnivores through H Gene Amplification and Sequencing.

Canine distemper virus (CDV) is recognised worldwide as an important pathogen in both domestic and wild carnivores. Few data are available on its impact and spread on the wildlife/wildlife-domestic animal-environment interface. This study, aimed at developing a conservation-oriented control strategy, analysed 89 sick or deceased animals from 2019 to 2023 at the Wildlife Rehabilitation Centre in Torreferrussa. RT-PCR and sequencing of the partial H gene were used to detect and analyse CDV in tissues. The total positive percentage was 20.22% (18/89), comprising 13 red foxes (44.8%), 4 European badgers (28.6%), and 1 American mink (4.5%), while 24 Eurasian otters tested negative. Phylogenetic analysis indicated that all of the CDV strains belong to the European lineage. Geographically distant individuals and different species shared the same viral strain, suggesting a strong capacity of CDV for interspecies and long-distance transmission. This calls for further research, particularly focusing on potential impacts of CDV on endangered carnivores.

Otterly delicious: Spatiotemporal variation in the diet of a recovering population of Eurasian otters (Lutra lutra) revealed through DNA metabarcoding and morphological analysis of prey remains.

Eurasian otters are apex predators of freshwater ecosystems and a recovering species across much of their European range; investigating the dietary variation of this predator over time and space, therefore, provides opportunities to identify changes in freshwater trophic interactions and factors influencing the conservation of otter populations. Here we sampled feces from 300 dead otters across England and Wales between 2007 and 2016, conducting both morphological analyses of prey remains and dietary DNA metabarcoding. Comparison of these methods showed that greater taxonomic resolution and breadth could be achieved using DNA metabarcoding but combining data from both methodologies gave the most comprehensive dietary description. All otter demographics exploited a broad range of taxa and variation likely reflected changes in prey distributions and availability across the landscape. This study provides novel insights into the trophic generalism and adaptability of otters across Britain, which is likely to have aided their recent population recovery, and may increase their resilience to future environmental changes.

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.

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.

Morphology of aortic arch branching patterns in the Eurasian Otter (Lutra lutra, Linnaeus, 1758).

In this study, we investigated the aortic arch (AA) branching pattern in the Eurasian otter (Lutra lutra). We performed arterial silicone casting of the AA of 18 Eurasian otters (8 males and 10 females). We analyzed the AA branching pattern at three levels: the AA, brachiocephalic trunk (BCT), and subclavian artery (SB), using different classification methods at each level. We introduced new criteria for classifying the SB branching pattern applicable for Eurasian otter and other carnivores based on the sequence of the four main branches: vertebral artery (VT), internal thoracic artery (IT), costocervical artery (CCT), and superficial cervical artery (SC). In all Eurasian otters, two major branches emerged directly from the AA, i.e., the BCT and left SB. The BCT branched off the left common carotid artery and terminated in the right common carotid artery and right SB in 17 of 18 Eurasian otters; the BCT formed a bicarotid artery in the remaining case. The SBs showed various branching patterns, with the main branching pattern involving branching to the VT and IT at the same position, followed by the CCT and SC. The SB branching pattern in the Eurasian otter differed from that in dogs in that the two first branching arteries were VT and IT, rather than VT and CCT. Here, we present the anatomical characteristics of the AA branching patterns in the Eurasian otter and new analysis methods applicable for comparative studies of other carnivores.

Mercury concentration in the tissues of the Eurasian otter: a seasonal dependance in Slovakia.

The river otter is considered to be an important bioindicator of water clarity. This study focuses on mercury contamination within this species. Throughout the study, individuals from habitats in the foothills and surroundings of the Liptovská Mara reservoir were analyzed. Twenty-three samples of liver tissue, and twenty-two samples of hair and kidney tissue were collected. Of these samples, the average mercury concentration detected in tissues was 10.6 mg/kg in guard hairs; 12.9 mg/kg in under hairs; 3.3 mg/kg in kidney tissue; and 4.3 mg/kg in liver tissue. Analysis of certified reference material (ERM-BB186-Pig Kidney) was used to assist in the development of an accurate method for total mercury determination in animal tissues, to check the quality of measurements, and to validate the measurement method. Our method represented a high average percentage of recovery (> 95%) in the standard reference material matrix and a relative standard deviation (RSD) of 5% or less. Seasonality was determined to be a significant factor influencing the level of contamination of a given individual, both through mercury methylation within the aquatic environment and through fish ingestion by this apex semi-aquatic predator (guard hairs (p = 0.01); underfur (p = 0.04); kidney (p = 0.03); liver (p = 0.03)). Sex, location, and body size were not found to have a significant influence on heavy metal concentrations in river otters sampled in terms of season.

Characterizing the Gut Microbiota of Eurasian Otter (Lutra lutra chinensis) and Snub-Nosed Monkey (Rhinopithecus roxellana) to Enhance Conservation Practices in the Foping National Nature Reserve of China.

Understanding the interaction between the microbial composition in the habitat and the gut of wildlife will contribute to conservation efforts since changes in the gut microbiome have been proven to influence the healthy and nutritional status of the host. This study analyzed the relationship between soil microbes and the microbial diversity and structure of the distal gut of the terrestrial golden snub-nosed monkey and Eurasian otter in the Foping National Nature Reserve (FNNR). A total of 15 otter fecal samples and 18 monkey fecal samples were collected from which 5 and 6 samples, respectively, were randomly selected for microbiome analysis. The remaining samples were used for fecal short-chain fatty acids (SCFAs) analysis. Soil samples from the otter and monkey habitats at each sampling point (eight in total) were also collected for microbiome analysis. The microbial phyla with the greatest relative abundance in soil or animal samples were Proteobacteria (41.2, 32.7, and 73.3% for soil, otters, and monkeys, respectively), Firmicutes (0.4% soil, 30.1% otters, and 14.4% monkeys), Bacteroidota (5.6% soil, 17.0% otters, and 8.3% monkeys), and Acidobacteriota (24.6% soil, 1.7% otters, and 0.1% monkeys). The estimation of alpha diversity indices revealed that the feature, Chao1, and Shannon indices of the soil microbiome were the greatest (p < 0.01) among the three groups, followed by those of the otter microbiome and those of the monkey microbiome (p < 0.01). Beta diversity analyses confirmed differences in the microbiota of the three types of samples. The determination of SCFA concentration in feces revealed that total volatile fatty acids, acetic acid, and isovaleric acid were greater (p < 0.05) in otters than in monkeys, while propionic acid followed the opposite pattern (p < 0.05). Correlation analysis of the microbiome and SCFA contents showed that propionic acid was positively correlated with significantly different bacterial groups, while acetic and butyric acid and total volatile acids were negatively correlated. This study confirmed that the fecal microbes of Eurasian otters and golden snub-nosed monkeys in the reserve are related to the soil microbial communities of their habitats, but they have different bacterial community structures and compositions, and there are different SCFA metabolic patterns in the gut of the two animals. The present study will help to improve wildlife protection in the FNNR.

Factors Affecting Roadkills of Semi-Aquatic Mammals.

We previously showed that registration efforts and traffic intensity explain 90% of variation in mammal roadkill numbers, 70% of variation in the numbers of recorded species and 40% of diversity variation. Here we analyze semiaquatic mammal roadkill in Lithuania in 2002-2021, relating these to the monitoring effort. From 39,936 analyzed roadkill, the European beaver (Castor fiber) was registered 60 times, American mink (Neovison vison) 26 times, otter (Lutra lutra) 22 times and muskrat (Ondatra zibethica) 3 times. The average roadkill indexes were 0.000065, 0.00076, 0.00061 and 0.00010 ind./km/day, and the extrapolated annual roadkill for the country was 44-357, 36-456, 49-464 and 89-144 individuals, respectively. Beaver roadkill numbers correlated with the registration effort and traffic intensity, otter roadkill with registration effort only and mink with hunting bag (number of hunted individuals per year). Roadkill was not always related to proximity to water, with 38-54% of roadkill occurring over 200 m from the nearest water source. With American mink and muskrat being invasive species in the EU and otter protected in many countries, it is valuable to enhance the registrations of their roadkill (using targeted efforts by drivers, hunters or other citizen scientists) to obtain the extrapolated amount of roadkill and to use this knowledge in species management.

Revisiting Rustrela Virus: New Cases of Encephalitis and a Solution to the Capsid Enigma.

Rustrela virus (RusV; species Rubivirus strelense) is a recently discovered relative of rubella virus (RuV) that has been detected in cases of encephalitis in diverse mammals. Here, we diagnosed two additional cases of fatal RusV-associated meningoencephalitis in a South American coati (Nasua nasua) and a Eurasian or European otter (Lutra lutra) that were detected in a zoological garden with history of prior RusV infections. Both animals showed abnormal movement or unusual behavior and their brains tested positive for RusV using specific reverse transcription quantitative PCR (RT-qPCR) and RNA in situ hybridization. As previous sequencing of the RusV genome proved to be very challenging, we employed a sophisticated target-specific capture enrichment with specifically designed RNA baits to generate complete RusV genome sequences from both detected encephalitic animals and apparently healthy wild yellow-necked field mice (Apodemus flavicollis). Furthermore, the technique was used to revise three previously published RusV genomes from two encephalitic animals and a wild yellow-necked field mouse. When comparing the newly generated RusV sequences to the previously published RusV genomes, we identified a previously undetected stretch of 309 nucleotides predicted to represent the intergenic region and the sequence encoding the N terminus of the capsid protein. This indicated that the original RusV sequence was likely incomplete due to misassembly of the genome at a region with an exceptionally high G+C content of >80 mol%. The new sequence data indicate that RusV has an overall genome length of 9,631 nucleotides with the longest intergenic region (290 nucleotides) and capsid protein-encoding sequence (331 codons) within the genus Rubivirus. IMPORTANCE The detection of rustrela virus (RusV)-associated encephalitis in two carnivoran mammal species further extends the knowledge on susceptible species. Furthermore, we provide clinical and pathological data for the two new RusV cases, which were until now limited to the initial description of this fatal encephalitis. Using a sophisticated enrichment method prior to sequencing of the viral genome, we markedly improved the virus-to-background sequence ratio compared to that of standard procedures. Consequently, we were able to resolve and update the intergenic region and the coding region for the N terminus of the capsid protein of the initial RusV genome sequence. The updated putative capsid protein now resembles those of rubella and ruhugu virus in size and harbors a predicted RNA-binding domain that had not been identified in the initial RusV genome version. The newly determined complete RusV genomes strongly improve our knowledge of the genome structure of this novel rubivirus.

Health and Mortality Monitoring in Threatened Mammals: A First Post Mortem Study of Otters (Lutra lutra L.) in Italy.

Dead specimens provide valuable data for the conservation of threatened species, allowing investigations of mortality, health conditions, and demographic parameters. The Eurasian otter (Lutra lutra) is a semiaquatic carnivore listed as endangered in Italy. In 2009, we started the first post mortem (PM) study of otters in Italy, through collaborative research between mammal ecologists and veterinary pathologists, using standardized protocols. Twenty-eight otters, mostly collected between 2009 and 2017, were examined. Most otters were males (67%), between 1 and 3 years old (64%), and predominantly in good nutritional condition. Adult males were significantly larger than adult females (p < 0.02), as expected for the species, although both sexes appeared to be smaller than otters examined in Central−northern Europe. The youngest sexually mature female was 3 years old. Road traffic collisions were the major cause of death, especially in young individuals, and mainly occurred in autumn−winter, particularly for females. Investigations of the scene of death contributed to revealing factors forcing otters to travel out of the water and move over the road, suggesting appropriate measures to reduce vehicle collision risk. Other causes of death included blunt chest trauma of uncertain origin, dog and conspecific attacks, or diseases of infectious or non-infectious origin, such as ulcerative gastritis, pleuropneumonia and peritonitis. Other diagnosed diseases included lymphoma. Ecto- and endoparasites were rarely detected, although we report the first documentation of heartworm and Ixodes hexagonus infestation in Italian otters. It is important to continue comprehensive, standardized PM investigations of otters in Italy to define baseline health, biometric and demographic parameters, collect biological samples for comparative analyses, and to reduce road-kill mortality. The present study suggests that the timely collection of carcasses and collaborative and coordinated research efforts are essential for obtaining useful data for the conservation of otters.

Anthropogenic Drivers of Variation in Concentrations of Perfluoroalkyl Substances in Otters (Lutra lutra) from England and Wales.

Per- and polyfluoroalkyl substances (PFASs) are ubiquitous environmental contaminants that have been linked to adverse health effects in wildlife and humans. Here, we report the presence of PFASs in Eurasian otters (Lutra lutra) in England and Wales and their association with anthropogenic sources. The following 15 compounds were analyzed: 10 perfluoroalkyl carboxylic acids (PFCAs), 4 perfluoroalkyl sulfonic acids (PFSAs), and perfluorooctane sulfonamide, in livers of 50 otters which died between 2007 and 2009. PFASs were detected in all otters analyzed, with 12/15 compounds detected in ≥80% of otters. Perfluorooctane sulfonate (PFOS) accounted for 75% of the ΣPFAS profile, with a maximum concentration of 6800 µg/kg wet weight (ww). Long-chain (≥C8) PFCAs accounted for 99.9% of the ΣPFCA profile, with perfluorodecanoic acid and perfluorononanoic acid having the highest maxima (369 µg/kg ww and 170 µg/kg ww, respectively). Perfluorooctanoic acid (PFOA) concentrations were negatively associated with the distance from a factory that used PFOA in polytetrafluoroethylene manufacture. Most PFAS concentrations in otters were positively associated with load entering wastewater treatment works (WWTW) and with arable land, suggesting that WWTW effluent and sewage sludge-amended soils are significant pathways of PFASs into freshwaters. Our results reveal the widespread pollution of British freshwaters with PFASs and demonstrate the utility of otters as effective sentinels for spatial variation in PFAS concentrations.

Three neoplasms in a Eurasian otter (Lutra lutra): malignant melanoma, trichoblastoma and mammary gland adenoma.

An eighteen-year-old female Eurasian otter became emaciated and died. Necropsy examination revealed nose and thoracic cutaneous masses, abdominal subcutaneous mass, and multiple nodules in the liver and lungs. Malignant melanoma was found in the nose cutaneous mass and to have metastasized to the liver, lungs, kidneys, adrenal glands, mammary glands and left mandibular lymph node. The neoplastic cells were labeled for vimentin, melanoma, and S100. The cutaneous mass in the thoracic area consisted of spindle shaped neoplastic epithelial cells and was diagnosed as trichoblastoma. Mammary gland adenoma was observed in the abdominal subcutaneous mass. This is the first report of primary three neoplasms of malignant melanoma, trichoblastoma and mammary gland adenoma in a Eurasian otter.

Pathological Findings in Eurasian Otters (Lutra lutra) Found Dead between 2015-2020 in Schleswig-Holstein, Germany.

In times of massive biodiversity loss and ongoing environmental crises, it is extremely important to ensure long-term conservation efforts of threatened species like Eurasian otters (Lutra lutra). To gain insights into the status of Northern Germany's otter population, 92 otters found dead in Schleswig-Holstein between 2015-2020 were collected and underwent detailed dissection with the aim to establish a monitoring program for this population. Examinations followed a protocol especially designed for otters, including various biological data assessments and extended sampling. The finding sites showed a clear concentration in the Continental region. Seasonal concentration differed among the years, yet peaks were seen from fall to winter. Overall, more males than females were found, although this differed among the years. The majority of otters that could be aged were between 1-3 years. Placental scars and pregnancy were recorded in only few females. Nutritional status was good in most cases. Infectious diseases found included Vagococcus lutrae, Toxoplasma gondii, and Emmonsia spp. A major cause of death was roadkill. Known sample bias in studies focusing on roadkill was considered in the finding interpretation. Continuation of the population health investigations is mandatory to analyze potential trends and to establish an actual monitoring program for Eurasian otters in Schleswig-Holstein.

Pulmonary hair embolism in a rescued free-ranging Eurasian otter Lutra lutra in Kinmen, Taiwan.

Eurasian otters Lutra lutra are listed as Near Threatened on the IUCN Red List and are imperiled by habitat loss, water pollution, and poaching. Harassment and attacks by stray animals are also recognized threats to the health of wild Eurasian otters. Pulmonary hair embolism is a possible complication in animals with deep traumatic injury, but to date no cases have been reported in wildlife. A free-ranging, adult male Eurasian otter was rescued due to severe emaciation and multiple bite wounds. The otter died 3 d after rescue and was necropsied. Grossly, a 1.5 × 1.5 × 1.5 cm firm nodule was observed in the left cranial lung lobe. Histologically, a fragment of hair shaft surrounded by multinucleated foreign body giant cells was observed in a medium-sized vein, and extensive eosinophilic infiltration was noted in the adjacent vascular wall and lung parenchyma. Based on the gross and histological findings, the pulmonary lesion was consistent with eosinophilic pneumonia and vasculitis induced by hair embolism. The presence of well-formed multinucleated foreign body giant cells and eosinophils may imply a late stage of foreign body reaction, and thus the presumptive source of hair embolism is an animal bite. This is the first report of pulmonary hair embolism associated with animal bite in a rescued free-ranging Eurasian otter.

Clinical leishmaniosis in a captive Eurasian otter (Lutra lutra) in Spain: a case report.

BACKGROUND: Captive and free-ranging wild mammals have been recognized as potential reservoirs of Leishmania infantum infection. The aim of this study was to describe the first clinical case of leishmaniosis in the Eurasian otter. CASE PRESENTATION: A case of clinical leishmaniosis is reported in a 4-year-old male Eurasian otter housed at a wildlife park (Murcia, South Eastern Spain). The Eurasian otter showed bilateral epistaxis, anorexia, apathy, and weight loss. A complete blood cell count and biochemical analyses revealed hyperproteinemia, hyperglobulinemia, decreases of paraoxonase-1, increases of haptoglobin and ferritin, and proteinuria. Bilateral nephropathy with hydronephrosis, mesenteric lymphadenomegaly, and ascites were also observed. L. infantum infection was confirmed by microscopy (amastigotes were detected in macrophages from spleen aspirate), molecular diagnosis (L. infantum DNA was detected by real-time polymerase chain reaction), and serology (anti-Leishmania IgG2 antibodies were detected by time-resolved immunofluorometry). The animal was treated with allopurinol for 3 months and gained weight, the epistaxis disappeared, and the ferritin concentration decreased. CONCLUSIONS: This is the first report of clinical leishmaniosis in the Eurasian otter. Our results suggest that Eurasian otters are susceptible to infection with L. infantum and can develop clinical leishmaniosis in endemic areas.

First study on PCBs, organochlorine pesticides, and trace elements in the Eurasian otter (Lutra lutra) from southern Italy.

Persistent organic pollutants (POPs), such as organochlorine pesticides (OCPs) and non dioxin-like polychlorinated biphenyls (ndl-PCBs), or also other toxic and potentially toxic elements tend to accumulate in the trophic web, and are associated with a wide range of deleterious effects in animals and humans. Although these contaminants have been banned since more than 30 years, their occurrence remains widespread in most of natural ecosystems. The Eurasian otter (Lutra lutra), being a top predator may cumulate large amounts of these contaminants, and could represent a keystone species serving as sentinel of ecosystem health in freshwater environments. The aim of this paper was to investigate the concentration of OCPs, ndl-PCBs, and essential and not essential elements in tissue samples of Eurasian otter in southern Italy. Six PCBs, seven OCPs, and thirteen trace elements were detected with high concentrations in few cases, however in general, the amounts of toxic compounds seem unlikely to hazard short-term conservation of this endangered mammal. The present paper is the first to provide baseline information concerning the presence of these substances in the Eurasian otter samples and from its fragile ecosystem in Italy.

Left atrial appendage rupture due to blunt chest trauma in an Eurasian otter (Lutra lutra).

An adult male Eurasian otter, found dead on the roadside, was submitted for post-mortem examination in April 2014 at the Veterinary Pathology Unit of the Faculty of Veterinary Medicine of Teramo, as part of the RECAL [RECovery and post mortem Analysis of Eurasian otters (Lutra lutra) in the National Park of Cilento, Vallo di Diano and Alburni (Salerno, Italy), and surrounding areas] project. Necropsy revealed an abundant hemothorax associated with multifocal, bilateral pulmonary contusions and lacerations, and a severe hemopericardium characterised by the presence of a wide blood clot in the intact pericardial sac. Two small laceration wounds of the left auricle were found at the base, along the atrioventricular groove, and on the outer free wall. Since myocardial and endocardial tissues showed no other gross and histopathological abnormalities, a left atrial appendage rupture resulting from a blunt chest trauma was diagnosed. Blunt traumatic cardiac rupture is a rarely reported, life-threatening condition in humans. To the best of our knowledge, this is the first report on a left atrial appendage rupture due to blunt chest trauma in veterinary literature. The possible occurrence of a cardiac rupture following a blunt thoracic injury should be taken into consideration in veterinary emergency care.

Where will it cross next? Optimal management of road collision risk for otters in Italy.

Collisions with vehicles represent the main conflict between infrastructures and wildlife, causing damages to both humans and animals. As to the latter, road mortality is a growing phenomenon and the largest single cause of death for many vertebrates. When focusing on endangered species, the Eurasian otter (Lutra lutra) is among the most vulnerable to road-kills, which represent the predominant cause of deaths recorded in Europe. We propose a large scale spatially-explicit assessment of road-kill risk for the Eurasian otter in Italy as a tool to identify road stretches at high collision risk, thus optimizing the location of mitigation measures. The modelling approach was produced for South Central Italy, hosting the only remnant viable population of otters in Italy. We used a maximum entropy approach including 56 road collision events recorded between 2004 and 2016 through a citizen science initiative, along with seven environmental predictors measured on 1 km grid cells. Four predictors were selected to describe roads characteristics, i.e. density of highways, and of state, regional and local roads. The remaining three variables referred to the quality of otter habitat in the surrounding of the collision sites, i.e. elevation, density of freshwater bodies, and a measure of landscape heterogeneity calculated on land-cover categories. The model achieved a good predictive accuracy (AUC > 0.8; Boyce index > 0.8). The collision probability was mostly affected by elevation, density of state roads, and density of freshwater bodies. Specifically, collision risk was higher in areas at low elevation and medium density of state roads located near rivers and wetlands. In addition, model predictions evidenced that implementing mitigation measures along 10% of road network in the study area could have potentially hampered ca. 50% of otter casualties recorded during the study period.