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The study aimed to evaluate the comparative anatomy of the liver and intrahepatic branching of the portal vein of the Eurasian otter (Lutra lutra) and the American mink (Neovison vison). Due to their highly valuable fur, minks have expanded their range to many parts of Europe and become available for many biomedical studies. In this study, ten adult minks and five otters were used. The intrahepatic branching of the portal vein was studied by the combined injection and dissection technique. The macroscopic anatomy of the liver revealed that both species have six-lobed livers, although differences in shape, size and some additional fissures were documented. The portal vein, upon entering the liver, divides into the right and left branches. The branching pattern in otters had an additional branch at this level with a caudate process branch. The right branch of the portal vein ramified in the right lateral lobe and the caudate process in the mink livers, while the right branch in the otter livers only distributed functional blood to the right lateral lobe. The larger left portal branch, with its transverse and umbilical parts, ramified in the left liver portion, along with the quadrate, right medial lobe and papillary process.

Angiotensin converting enzyme 2 (ACE2) is a host cell membrane protein (receptor) that mediates the binding of coronavirus, most notably SARS coronaviruses in the respiratory and gastrointestinal tracts. Although SARS-CoV-2 infection is mainly confined to humans, there have been numerous incidents of spillback (reverse zoonoses) to domestic and captive animals. An absence of information on the spatial distribution of ACE2 in animal tissues limits our understanding of host species susceptibility. Here, we describe the distribution of ACE2 using immunohistochemistry (IHC) on histological sections derived from carnivores, ungulates, primates and chiroptera. Comparison of mink (Neovison vison) and ferret (Mustela putorius furo) respiratory tracts showed substantial differences, demonstrating that ACE2 is present in the lower respiratory tract of mink but not ferrets. The presence of ACE2 in the respiratory tract in some species was much more restricted as indicated by limited immunolabelling in the nasal turbinate, trachea and lungs of cats (Felis catus) and only the nasal turbinate in the golden Syrian hamster (Mesocricetus auratus). In the lungs of other species, ACE2 could be detected on the bronchiolar epithelium of the sheep (Ovis aries), cattle (Bos taurus), European badger (Meles meles), cheetah (Acinonyx jubatus), tiger and lion (Panthera spp.). In addition, ACE2 was present in the nasal mucosa epithelium of the serotine bat (Eptesicus serotinus) but not in pig (Sus scrofa domestica), cattle or sheep. In the intestine, ACE2 immunolabelling was seen on the microvillus of enterocytes (surface of intestine) across various taxa. These results provide anatomical evidence of ACE2expression in a number of species which will enable further understanding of host susceptibility and tissue tropism of ACE2 receptor-mediated viral infection

The distribution of the American mink in the wild, originating either from accidental escapes or intentional releases from fur farms, was mapped for the first time in Greece, based on opportunistic data collected from 2010 to 2020. Greece is a key actor in Europe’s fur industry, with most mink farms operating in the northwest. Massive intentional releases by activists took place in the late 2000s, while accidental escapes regularly occur. Most mink were recorded in the Region of Western Macedonia, in NW Greece, within and around the core areas of fur farms, where feral populations became established. Animals were also found further south in the Regions of Thessaly (central Greece) and Central Macedonia (northern Greece). Half of mink records were close to protected areas and almost two-thirds near to watercourses. Many animals were away from the water and on high altitudes, with theoretically less favourable conditions for their survival. We also examine possible directions of further mink range expansion in Greece and neighbouring countries through the river network. Mink invasion progress in Greece is little known, thus, the subject is in urgent need of study, as mink is the alien mammal with the highest impact on the European native fauna.

A well-studied predator–prey relationship between American mink (Neovison vison (Schreber, 1777); formerly known as Mustela vison Schreber, 1777) and muskrats (Ondatra zibethicus (Linnaeus, 1766)) in Canada has advanced our understanding of population cycles including the influence of density dependence and lagged responses of predators to prey abundances. However, it is unclear if patterns observed in Canada extend across the southern half of their native range. We used data from the United States to create a 41-year time series of mink and muskrat harvest reports (1970–2011) for 36 states. After controlling for pelt-price effects, we used second-order autoregressive and Lomb–Scargle spectral density models to identify the presence and periodicity of muskrat population cycles. Additionally, we tested for evidence of delayed or direct density dependence and for predator-driven population dynamics. Our results suggest muskrat populations may cycle in parts of the United States; however, results varied by modeling approaches with Lomb–Scargle analyses providing more precise parameter estimates. Observed cycle lengths were longer than expected with weak amplitudes and we urge caution when interpreting these results. We did not detect evidence of a predator–prey relationship driven by a lagged numerical response of American mink. American mink and muskrat fur returns were largely correlated across the region suggesting extraneous factors likely synchronize both populations.

This work aims to establish a simplified genotype for American mink (Neovison vison), on the basis of a group of basic genes (Asip, Tyrp–1, Tyr, Myo–5a, and Mc–1r) and three modifying genes (fawn, Ednrb, and Kit). The analysis used pedigrees of 61 females of standard brown, palomino, and silverblue colour variations. The database covered 380 offspring in nine colour variations: brown, silverblue, palomino, brown cross, palomino cross, pearl, pastel, silverpastel, and white. The analysis led to a simplified genotype explaining the principles of inheritance of most common coat colour variations in Polish mink farms. Due to the limited number of animals and the limited number of colour variations used, the analysis could not test the inheritance of all colours found in mink. The genotype was constructed on the basis of the homologous genes responsible for coat colour found in most animal species.

Parasites may negatively affect hosts condition, especially when infection intensity is high. Species introduced to a new habitat are often less exposed to a parasite pressure but may accumulate parasites in time. American mink (Neovison vison) introduced to Europe, Asia, and South America is an example of such invasive species. We analysed nematode prevalence and digestive tract infection intensity in 796 feral American mink from Poland. The analyses were performed separately for stomach, duodenum, small intestine and large intestine. Parasite species identification was performed using molecular methods based on highly conserved nuclear 18S rRNA gene and supplemented with morphological analysis. In total, we collected 26,852 nematodes and 98.6% of them were isolated from mink stomachs. We found positive association between infection intensity in stomach and other parts of digestive tract. Nematode prevalence was estimated at 63.8% and average infection intensity per one American mink at 52.9 (range from 1 to 1118). If the stomach results were theoretically and intentionally omitted the prevalence was 5 times lower (12.7%) and infection intensity 14 times lower (3.7; range 1–50). We identified two nematode species in digestive tracts of American mink: Aonchotheca putorii and Molineus patens. The 18S rRNA gene sequence of Molineus patens has been reported for the first time. The results showed that Aonchotheca putorii is a dominating nematode in the invasive American mink and that it inhabits stomach intensively and preferably.

The study was aimed to evaluate a possible effect of body condition of female farmed mink (Neovison vison) at the moment of conception on their prospective reproduction and behavior. 601 Perl mink females at age 1 and 2 years were assigned to one of five groups according to their body condition. The following parameters were analyzed: gestation and diapause lengths, litter size, live-born litter size, number of weaned per litter, female barrenness, and the incidence of fur-chewing. The effect of body condition was more pronounced in yearling females, where the largest litters, the highest number of live-born per litter, and the highest weaning success were found in the group with the ideal body condition. In both age groups, the shortest pregnancies and diapause periods were observed in the thinnest females. Fur-chewing was most often noticed in either the thinnest or the most obese animals; females of these groups also exhibited the highest rates of barrenness. Consequently, the lowest incidence of fur-chewing, female barrenness were found in females with ideal body condition.

The aim of the study was to estimate the values of metric traits of selected mink heart veins of standard and mutation colour variants. The study was conducted on 342 hearts of seven-month-old males and 405 hearts of seven-month-old females. Mink colour, resulting from mutation or from crossbreeding mutational colour variants with each other. Metric traits of the coronary sinus, great cardiac vein, middle cardiac vein, posterior vein, and small cardiac vein were determined by photographic recording of the sub-epicardial picture of these vessels after filling them with a water-dilutable dye for acrylic paints together with a 30% food gelatin solution. In addition, the number of the veins forming the great cardiac vein and that of the posterior veins of the left ventricle were determined. Based on the measurement of the width and length of the mink hearts, the heart shape was determined. Differences were found between the traits of the mink heart vessels of standard and mutational colour variants, but they did not allow to formulate clearly the thesis about the effect of mutations on these traits.

Enterocytozoon bieneusi is a zoonotic pathogen that infects a variety of hosts including humans, livestock, wildlife, companion animals, and birds, as well as being abundant in the environment. Humans and nonhuman animals could be infected with E. bieneusi via consumption of food or water that contains zoonotic and host-adapted genotypes. In this study, 288 fecal specimens were collected from farmed minks, blue foxes, and raccoon dogs, in Xinjiang, China. Enterocytozoon bieneusi was examined by PCR amplification based on sequence analysis of the internal transcribed spacer (ITS) region. The overall infection rate of E. bieneusi was 4.9% (14/288), with mink samples showing the highest infection rate (5.6%, 12/214), followed by blue foxes (2.9%, 1/35), and then raccoon dogs (2.6%, 1/39). Six E. bieneusi genotypes were identified, including D (n = 5), PigEBITS7 (n = 4), EbpA (n = 2), CAM5 (n = 1), WildBoar3 (n = 1), and a novel genotype XJMI-1 (n = 1). Phylogenetic analysis showed that all E. bieneusi genotypes belonged to group 1, which composed of over 300 genotypes and most of them have been identified in human and variety of animals, suggesting a risk of zoonotic transmission from farmed wildlife to humans., Graphical abstract Image 1, Highlights • Six genotypes were identified, including three zoonotic genotypes (D, EbpA ad PigEBIST7). • Farmed wildlife maybe a potential source of E. bieneusi infection for other animals and humans.

American mink Neovison vison is a semi-aquatic mustelid that has been introduced throughout Europe. Several attempts to eradicate this invasive species have been carried out since its spread. In the Iberian Peninsula, an eradication program has started since 2001, as part of the national action plan for the conservation of European mink Mustela lutreola. Proper detection is crucial for management, both for monitoring variation in mink abundance and prevent the recolonization of cleared areas. Mink scats can be confounded with those of several same-sized mustelids, and with the spraints of Eurasian otter Lutra lutra, which also occur along watercourses. However, these difficulties can be overcome by non-invasive genetic methods. With the aim of providing a cost-effective and reliable technique for differentiating mink scats from those of the largest possible number of species with morphologically similar scats, we tested the effectiveness of an already available faecal mtDNA-based PCR–RFLP method for distinguishing mink- and otter faeces. We then applied the method for analysing scats collected and identified in the field by trained surveyors for monitoring the success of mink control operations. The PCR–RFLP method clearly differentiated mink scats from those of otters, as restriction enzymes produced well-defined different patterns. Eighty-five percent of 94 faecal samples could be assigned to a mustelid species. Only three out of seven putative mink samples were confirmed, suggesting that the accuracy of the visual identification of scats is questionable and genetic methods are needed for the reliable assessment of the success of eradication programs.

American mink Neovison vison is one of the most harmful non-indigenous species in Iceland and has been proven to be a useful indirect bioindicator and biomonitor for numerous environmental pollutants. Therefore, the main objective of the study was to determine the total nickel concentration in the spleen of 35 females and 30 males obtained from Brokey archipelago and the south coast of Hvammsfjörður (Dalabyggð, Iceland) using graphite furnace atomic absorption spectroscopy. We also assessed the correlation between nickel concentration and selected anatomical and morphological parameters, hypothesising that invasive alien N. vison is a promising candidate species for biomonitoring the deposition of this trace element. The results indicated a substantial variation in nickel concentration in the spleen tissue of examined animals. For males, the maximum concentration exceeded the average level by more than 16 times, and for females by more than 7 times. The correlation coefficient between morphometric features and the level of nickel concentration in the spleen did not show a significant relationship in any of the tested combinations, for all tested animals or for each sex separately. In conclusion, American mink in Iceland can be considered a promising species for qualitative and quantitative assessment of ecosystems in terms of nickel pollution.

American mink (Neovison vison) is both a problematic invader and an economically valuable fur breed species in Belarus. The increasing scale of mink breeding for fur and the growing impact of this invasive species on the local ecosystems requires sound, novel strategies for managing both farm and wild populations. Containment of wild American mink populations under the effects of possible migration from the fur farms could be especially problematic. With that issue in mind, we have used microsatellite analysis todetermine the genetic polymorphism in two color breeds of farm-bred American mink in the populations of several Belorussian model fur farms, as well as the same characteristics for the feral populations on the territories adjacent to said fur farms. We confirm the presence of effective influx of mink into the wild from fur farms, determined through the means of analyzing microsatellite genotype data of feral and farm populations.

Pathogens are one of the factors driving wildlife population dynamics. The spread of pathogens in wildlife is currently highly related to the transmission of pathogens from farmed animals, which has increased with the constant development of farming. Here, we analysed the spatio‐temporal variation in the prevalence of Aleutian mink disease virus (AMDV) antibodies in feral American mink (Neovison vison) populations in Poland (1,153 individuals from nine sites) in relation to mink farming intensity. AMDV was detected in feral mink at all study sites and the prevalence ranged from 0.461 in the northern region to 0.826 in the western region. Mink males and adults were infected more often than females and subadults; the infection was also more frequent during the mink breeding season than during non‐breeding. The prevalence of AMDV changed non‐linearly in consecutive years and the peak of prevalence was every 3–4 years. The predicted AMDV prevalence was low at sites where the number of farmed mink was also low and increased linearly with the increase in the number of mink kept on farms. The predicted AMDV prevalence at sites with low mink farming intensity strongly varied between years, whereas at sites with high mink farming intensity, the predicted prevalence did not change significantly. AMDV infection affected the mink's body condition and caused an increase in the size of the spleen, liver and kidneys. This study shows that Aleutian mink disease strongly affects feral mink but the spatio‐temporal variation of its prevalence is complex and partly related to the transmission of the virus from farmed mink to feral populations. The study highlights the complexity of AMDV circulation in feral mink populations and implicates a potential spillover of the virus to native species.

Coat colour is one of the most important qualitative traits of fur animals. Determining melanin pigments forming the basics of visible coat colour may contribute to a better understanding of the process of creating different coat colour variations in fur-bearing animals. This study aimed to (i) isolate pigment cells from the hair of American mink of 11 colour variations (standard brown, silverblue, palomino, black, wild type, sapphire, black cross, pearl, palomino cross, glow, and amber) using acid and alkali; and (ii) characterise the melanin pigments obtained. The purified pigment cells were observed under a light microscope and verified by spectrophotometry scanning and nuclear magnetic resonance spectroscopy. The method allowed for obtaining pure melanin specimens. Using acid and alkali to extract eumelanosomes did not affect their shape and structure; it also allowed for obtaining pheomelanin from the hair. The results have proven that the hair colour of the American mink is based on all types of melanin, and that its variations differ in terms of how much eumelanin and pheomelanin the hair contains.

From a longitudinal survey conducted on 30 Danish mink farms in 2016, 11.0% of faecal samples (456/4140) were positive for Cystoisospora laidlawi oocysts by microscopy, with 60% (189/315) of mink being positive at least once during the study period. Morphological analysis of sporulated oocysts identified Cystoisospora oocysts measuring 34.3 × 29.5 μm with an oocyst length/width (L/W) ratio of 1.2. The morphological features of the oocysts were identical to Isospora laidlawi previously morphological identified in farmed mink from Denmark and elsewhere. Phylogenetic analysis of 18S rDNA sequences (1221 bp) from three positive mink indicated that Cystoisospora from mink shared the highest genetic similarity to C. canis from a Canadian dog (99.6%). The phylogenetic analysis placed Cystoisospora from mink in a clade with other Cystoisospora isolates.

The release of domestic organisms to the wild threatens biodiversity because the introduction of domestic genes through interbreeding can negatively impact wild conspecifics via outbreeding depression. In North America, farmed American mink (Neovison vison) frequently escape captivity, yet the impact of these events on functional genetic diversity of wild mink populations is unclear. We characterized domestic and wild mink in Ontario at 17 trinucleotide microsatellites located in functional genes thought to be associated with traits affected by domestication. We found low functional genetic diversity in both mink types, as only four of 17 genes were variable, yet allele frequencies varied widely between captive and wild populations. To determine whether allele frequencies of wild populations were affected by geographic location, we performed redundancy analysis and spatial analysis of principal components on three polymorphic loci (AR, ATN1 and IGF‐1). We found evidence to suggest domestic release events are affecting the functional genetic diversity of wild mink, as sPCA showed clear distinctions between wild individuals near mink farms and those located in areas without mink farms. This is further substantiated through RDA, where spatial location was associated with genetic variation of AR, ATN1 and IGF1.

Commercial farming of endangered wildlife has potential to reduce poaching pressure on wild populations. However, poached products can be laundered as farmed products. A method for separating farmed from wild products is therefore essential for effective law enforcement. Meat (skeletal muscle) is a wildlife product whose origin cannot be correctly determined. This short communication reports an epigenetic approach to achieve the distinction using the methylation rate of the promoter of the α-actinin-3 (ACTN3) gene in gluteus maximus tissues of feral (n = 21) and farmed (n = 21) American mink, Neovison vison. Our results showed that the accuracy of assignment ranged from 59.5 to 76.2% on each of six CpG sites/site groups. Combination of the six CpG sites/site groups achieved 83.3% overall correct assignment, 90.5% for the farmed group and 76.2% for the wild group. These data suggest the methylation rate of promoters of selected genes could be an effective indicator to distinguish farmed meat from wild meat of wildlife species.

Detection probability is an important input when studying and managing species. It reduces the miscalculations of the estimates of occupancy, population abundances and their trends inherent to the imperfect detection during sampling. However, detection probability may vary in relation to environmental and biological factors, such as the presence of other species of similar ecological niche. We used a two-species single-season occupancy model to analyse the detection probability of the native Eurasian otter Lutra lutra and the invasive American mink Neovison vison in the northeast of the Iberian Peninsula and to test for potential differences in their detection when co-occurring and when not. Despite the known behavioural change of American mink towards a more terrestrial diet and a more diurnal activity pattern in the presence of Eurasian otter, their detectability did not vary when both species co-occurred versus when they did not. However, we observed seasonal differences in the probability of detection. Specifically, the probability of detection was higher in winter for both species. Furthermore, Eurasian otter was more often detected in sites with clay substrate, whereas American mink in sites with clay and rocks. These results indicate that the effectiveness of monitoring of Eurasian otter and American mink remains independent of the species co-occurrence. Yet, seasonal variations in the detection should be taken into account when monitoring.

Invasive non-native species can become reservoirs of zoonotic pathogens and cause their spread during colonization, increasing the risk of zoonoses transmission to both wild hosts and humans. American mink (Neovison vison) are considered an important invasive mammal species responsible for carrying endoparasites. The aim of our study was to evaluate the role of feral American mink as a possible transmission vector of Echinococcus spp. and Toxocara spp. in wildlife. We analysed the frequency of American mink exposure to both parasites, the spatial distribution in Poland, and the variability over time on the basis of specific antibody presence using ELISA and Western blot. Alimentary tract analyses revealed that American mink do not serve as definitive hosts for these parasites. Altogether, 1100 American mink were examined. The average seropositivity for American mink was 14.2% for echinococcosis and 21.7% for toxocarosis; dual-seropositivity was detected in only 6.0%. Seroprevalence of both parasites differed between study sites and significantly increased over time in Toxocara spp. Thus, our study revealed that free-living American mink are exposed to parasites and likely to be involved in the maintenance of both Echinococcus spp. and Toxocara spp. in the wild as paratenic hosts.

European and American minks (Mustela lutreola and Neovison vison, respectively) are very similar in their ecology, behavior, and morphology. However, the American mink is a generalist predator and seems to adapt better to anthropized environments, allowing it to outcompete the European mink in areas where it has been introduced, threatening the survival of the native species. To assess whether morphological differences may be contributing to the success of the American mink relative to the European mink, we analyzed shape variation in the cranium of both species using 3D geometric morphometrics. A set of 38 landmarks and 107 semilandmarks was used to study shape variation between and within species, and to assess how differences in size factored into that variation. Sexual dimorphism in both size and shape was also studied. Significant differences between species were found in cranial shape, but not in size. Relative to American mink, European mink have a shorter facial region with a rounder forehead and wider orbits, a longer neurocranium with less developed crests and processes, and an antero‐medially placed tympanic bullae with an anteriorly expanded cranial border. Within species, size‐related sexual dimorphism is highly significant, but sexual dimorphism in shape is only significant in American mink, not in European mink. Additionally, two trends common to both species were discovered, one related to allometric changes and another to sexual size dimorphism. Shape changes related to increasing size can be subdivided into two, probably related, groups: increased muscle force and growth. The first group somewhat parallels the differences between both mink species, while the second group of traits includes an anterodorsal expansion of the face, and the neurocranium shifting from a globous shape in small individuals to a dorsoventrally flattened ellipse in the largest ones. Finally, the sexual dimorphism trend, while also accounting for differences in muscle force, seems to be related to the observed dietary differences between males and females. Overall, differences between species and sexes, and shape changes with increasing size, seem to mainly relate to differences in masticatory‐muscle volume and therefore muscle force and bite force, which, in turn, relate to a wider range of potential prey (bigger prey, tougher shells). Thus, muscle force (and dietary range) would be larger in American mink than in European mink, in males than in females, and in larger individuals than in smaller ones., Cranial shape and size variation in European (Mlu) and American minks (Nvi) were studied. Both species differed in shape but not size, while sexes within each differed in size but in shape only for Nvi. Allometric shape changes were related to growth and sexual dimorphism. Overall, differences among species, sexes, and sizes related to masticatory‐muscle volume, which suggests that muscle force (and dietary range) would be larger in Nvi than in Mlu, in males than in females, and in larger mink.

The European mink (Mustela lutreola) is listed as a critically endangered species because of ongoing population reduction from habitat degradation and the effects of introduced species, such as American mink (Neovison vison). This small, fragmented population becomes vulnerable to many other threats, including diseases. Leishmaniosis is a zoonotic disease caused by the protozoan parasite Leishmania infantum found in the Mediterranean area, which affects many mammals, including wild small mammals. Furthermore, clinical disease caused by L. infantum has recently been described in other mustelids. To assess the exposure to Leishmania sp. infection in mink species in northern Spain, blood samples from 139 feral American mink and 42 native European mink from north Spain were evaluated for Leishmania sp. infection using enzyme-linked immunosorbent assays against Leishmania spp. antibodies, with 52.4% of American mink and 45.3% of European mink being found seropositive. This finding raises questions regarding how the disease may affect these species and the potential repercussions for conservation efforts. Despite a high seroprevalence being observed in wild mink of both species in this study, association with clinical or pathologic signs of disease has yet to be elucidated.

The American mink, Neovison vison, is an invasive species in Chile. Its impact on native fauna and public health has not been studied in depth in the country. In this study, we searched for gastrointestinal parasites, including helminths and zoonotic Cryptosporidium sp., the presence of Trichinella sp. in muscle, and the renal carriage of pathogenic Leptospira sp. in minks caught on Navarino Island, "Magallanes y la Antartica Chilena" Region, and Maullin and Ancud, "Los Lagos" Region, Chile. A total of 58, 15, and 21 minks from Navarino Island, Maullin, and Ancud, respectively, were examined for Trichinella sp. (artificial digestion of muscle). A total of 36, 11, and 17 minks from Navarino Island, Maullin, and Ancud, respectively, were examined for pathogenic Leptospira species (molecular detection of LipL32 gen fragment in renal tissue) infection. Finally, 45, 11, and 17 minks from Navarino Island, Maullin, and Ancud, respectively, were analyzed to detect gastrointestinal parasites (by optical inspection of the digestive tract for helminths, and by both Ziehl-Neelsen stain and molecular detection of small subunit-ribosomal DNA for Cryptosporidium species). Trichinella larvae were not observed. Pathogenic Leptospira sp. was detected in 22 samples: 15 from Navarino Island, 3 from Maullin, and 4 from Ancud. Two nematodes, belonging to Ascaridinae (subfamily) and Pterygodermatites (Paucipectines) sp., were found in samples of two minks from Navarino Island. Oocysts and DNA of Cryptosporidium sp. were detected in three fecal samples from Navarino Island. Further studies could determine the zoonotic potential of Cryptosporidium sp., as well as the potential impact of the zoonotic Leptospira sp. on the human population of the Navarino Island, Maullin, and Ancud districts. The enemy release theory could explain the low helminth species richness in the minks. In addition, we did not find evidence of parasite transmission from native fauna.

Reintroduction is an important strategy to restore or re-establish wild populations of endangered species. Pre-release training is a necessary step to ensure post-reintroduction survival. However, studies reported contradicting outcomes after pre-release training of juveniles and adults. This study used farmed and feral American mink (Neovison vison) to analyze the influence of captive breeding on the morphology, structure and efficiency of the two major hindlimb levers, the femur and tibia pivoted by hip and knee joints that are essential for locomotion. Results showed that captive breeding did not alter the sexual dimorphism of the two levers that are related to survival in the wild. Captive-bred mink showed slightly altered morphology of the femur and fundamental structure of the hindlimb levers that improved efficiency, but this resulted in reduction of performance related to foraging in both terrestrial and aquatic environments, especially for females. These findings suggest that reintroduction of mustelid as exampled by the mink here should focus on juveniles because the skeletal alterations associated with captive rearing were recorded only among adults and are irreversible in adulthood. In contrast, captive-reared juveniles showed no skeletal alterations and would be expected to recovery from any atrophy of the muscular system caused by captive rearing for shorter durations. Our results support the application of pre-release training of juveniles in enriched environments as a method for alleviating structural alteration of appendages and enhancing locomotion to increase survival probability in complex habitats.

Based on the materials of 23 fur-bearing animal farms of the Russia for different periods of years, a comparative assessment of the reproductive capacity of sable and mink females of standard breeds (wild type) has been carried out. It was established that during intrabreeding differentiation according to the overall color of the hair coat (almost black, black-brown, dark brown and chestnut), the lowest reproduction level is characterized by darker females of sable, which are a significant increase in the number of them, mated with male, but not given offspring (barren females). According to the results of interbreed comparisons of sables and minks, parallelism was found in the variability of the reproductive capacity of females, which is manifested in the fact that, in contrast to relatively light animals, animals that are dark in color are characterized by a greater number of barren females and low fecundity.

In this study we investigated the robustness of the WelFur welfare assessment system for farmed mink (Neovison vison) to date of assessment in the winter and growth assessment periods. The prevalence of occurrences of certain measurements was hypothesised to increase with date of assessment (too thin, fur-chewing and stereotypic behaviour in the winter period and injuries, diarrhoea and exploratory mink in the growth period). The welfare was assessed on eight Danish mink farms according to the WelFur-Mink protocol. Each farm was assessed once in the nursing period (to be able to calculate WelFur-Mink scores), four times in the growth period and three times in the winter period. WelFur scores were calculated based on the assessments in the three periods: one calculation for each assessment in the winter and growth periods. The odds of fur-chewing increased with date of assessment in the winter period, and the odds of injuries, diarrhoea and exploratory mink increased with date of assessment in the growth period. The odds of too thin mink in the winter period decreased, ie the change was in the opposite direction to what was expected. The effect of these changes on the aggregated WelFur scores on the higher levels was limited, but could potentially lead to changes in the overall welfare categorisation of farms if the principle scores were close to a threshold between two categories. A potential way to eliminate the effect of date of assessment could be to develop a correction factor for the measurements that can be expected to change within each assessment period.

The American mink Neovison vison has been introduced to Italy for fur farms in the 1950s. Since the 1970s, free-ranging individuals are present in north-eastern Italy, where an expanding population still occurs. In our work, we aimed at assessing the seasonal diet of invasive American mink introduced to north-eastern Italy. Thus, a total of 195 mink scats (N = 73, June 2007; N = 57, September 2007; N = 65, February 2008) were collected. Scats were washed and food remains isolated and classified through comparison with reference collections and atlases. Absolute and relative frequencies, as well as the estimated volume of each prey category were computed. The endemic Italian water vole Arvicola italicus represented the staple of the diet of the American mink in June (relative frequency: 20.4%, total volume in diet: 38.1%) and September (relative frequency: 22.7%, total volume in diet: 52.0%). Other small mammals, amphibians (Rana spp. and Pelophylax spp.) and the invasive red swamp crayfish Procambarus clarkii were mostly consumed in cold months, when water voles are not available. Differently from other study areas, wading birds and fish were rarely consumed, possibly because of their low local availability, if compared with small mammals. No law currently protects the endemic water vole, which may be furtherly threatened by the potential range expansion of invasive minks. Therefore, eradication of this alien carnivore should be recommended before local population decline of water vole become irreversible, and before minks reach populations of native riverine mustelids, i.e. the western polecat and the Eurasian otter.

Introduction: Farm mink (Neovison vison) can be naturally exposed to T. canis and T. leonina pathogens on the farm. If mink were hosts, it would imply some veterinary public health as well as animal welfare issues. For this reason, the aim of the study was to determine whether mink might be definitive or paratenic hosts of these parasites. Material and Methods: Four groups of mink were infected with both parasite species using larvated eggs or feed containing mouse tissue previously infected with the parasites. Following inoculation, the infections were monitored in vivo by faecal examination for 14 weeks p.i., and then western blotting and ELISA were performed. Results: Coprology did not reveal any canine roundworm eggs, neither were nematodes found in mink intestines during post mortem examination. The specific IgG antibodies recognising excretory/secretory (ES) antigens of both parasite species were identified in mink sera. Single T. leonina tissue larvae were found in digested organs. Conclusions: Our results confirm that farm mink may contribute both T. canis and T. leonina infections. It was proved that farm mink were not their definitive hosts, and therefore mink faeces need not be considered a source of canine roundworm eggs in any soil it fertilises. Nonetheless, as farm mink may be a paratenic host for both parasite species, this may have some impact on the health and welfare of infected animals.

Helminthological autopsies of Mustelids from various districts of Pskov, Тver and Smolensk region were carried out. To determine the prevalence rates of the infestation, an extensive invasion index was used. According to the results of helminthological autopsies, a list of detected helminthes is given. For the first time on the study area, 14 species of helminthes were recorded in studied Mustelids. Two of the found species of helminthes parasitize in Mustelids in larval form. The maximum variety of species is observed among the Nematoda class. The data on the number of detected helminth species in Mustelids in certain districts of the Tver, Pskov and Smolensk regions, as well as indicators of the frequency of helminthes were given. The maximum number of helminth species is recorded in Mustelids in the Novosokolnichesky district of the Pskov region. Extensiveness of invasion of all studied species of Mustelids, excluding otter, is 100%. According to the indicators of extensiveness of invasion in the studied Mustelids, Isthmiophora melis, Capillaria mucronata, Capillaria putorii, Filaroides martis are prevalent. The maximum number of species of parasitic worms is recorded in pine marten. The research results indicate the dominant influence of the trophic factor in the formation of the helminth fauna of martens that inhabit the study areas.

The aim of this review was to define the most important factors that affect the reproductive success of farmed mink. The biology of mink reproduction is unique when comparing it with other farmed fur animals. The article emphasizes the importance of optimal environmental conditions in prevention of reproductive disorders. The novel attempts to the mating schedule, optimal diet and body condition of dams, kits transfer between dams, these are only examples of advantageous procedures used in mink farming to increase the effectiveness of reproduction.

This paper reports the results of stationary studies on the ecology of the American mink (Neovison vison Schreb.) on three small rivers of the Sikhote-Alin region from 2003 to 2018. The population density in the field stations range from 0.4 to 2.2 individuals per 1 km of watercourse. Cyclic changes in the density of the mink population were found to occur with a period of about six years (rS = 0.68, P = 0.01). Hunting of low intensity did not affect the number and growth of the mink population. The correlation between floods and annual precipitation and dynamics of density was weak and unreliable. In the predator’s diet, three main forage groups (mammals, frogs, and fish) were singled out, the ratio of which varied in the basins of different rivers and according to the seasons of the year.

Invasive alien predators pose a threat to native fauna and the studies of their feeding habits are crucial to understanding their impact on prey populations. Diet of the American mink Neovison vison, an invasive species in Europe, is relatively well studied based on scat analysis, however, the use of other methods of diet analysis enables a better overview of this issue. We analyzed the isotopic composition of carbon and nitrogen in the livers, which reflects the diet from about 30–40 days (scat analysis provides information on the diet over 1–2 days only) of the American mink from four national parks in Poland and in the muscles of three types of mink prey (root voles, common frogs, and roach) in order to estimate their contribution to the mink diet. Mink in Biebrza and Narew National Parks fed mainly on frogs and fish, in Drawa National Park on voles and fish, and in Warta Mouth National Park almost exclusively on fish—as shown by Bayesian mixing models calculated for three selected groups of prey. There was no isotopic evidence for differences between the diets of male and female mink. In all groups of prey, we found surprisingly high differences between individuals of the same species from different study sites in the isotopic composition of both δ13C (up to 3‰) and δ15N (up to 6‰). Based on a detailed literature review, we predict that the main reasons for these variations are differences in abiotic environment, food availability, and trophic position. We also indicate a lack of data on trophic discrimination in fish and amphibians, which makes it hard to assess the influence of differences in trophic position on isotopic variations. We suggest caution to authors who plan to study geographical variations in diet of animals using stable isotope analysis without acknowledging that taxonomically and ecologically similar prey can differ in isotopic composition between studied areas.

he local landscape Feofaniya is located on the outskirts of the Kyiv and represents communities of native oak wood with high density of ancient trees and hornbeam forest, steppe meadow, culture phytocenoses, cascade of ponds, stream. For the period 2012-2018 11 species of fish, 8 amphibians, 7 reptiles, 111 birds, 29 mammals were identified. Of these, 82.0 % of species are protected internationally, 8.9 % at the state level of the Ukraine, 12.6 % are regionally rare. In 81% of animal species, the reproductive site passes through the tract, and in half of them the whole life cycle. 19 % of the species composition of birds (Aves) are sedentary, 58 % arrive for nesting, 12 % for feeding, 9 % for wintering, 2 % for migratory (Regulus ignicapillus, Nucifraga caryocatactes). 82.8 % of mammals (Mammalia) are sedentary, 10.3 % are migratory (Pipistrellus nathusii, Pipistrellus pygmaeu, Nyctalus leisleri), 6.9 % with unexplained status (Neovison vison, Capreolus capreolus). The local landscape has 12 alien species. Carassius gibelio, Ctenopharyngodon idella, Hypophthalmichthys molitrix released into ponds with the purpose of stocking. Trachemys seripta elegans bring vacationers to the ponds. Pseudorasbora parva, Perccottus glenii, Streptopelia decaocto, Dendrocopos syriacus, Phoenicurus ochruros, Serinus serinus, Ondatra zibet, Pipistrellus kuhlii, Neovison vison penetrated the local landscape independently from neighboring biotopes. Thanks to biotechnical measures aimed at improving the living conditions of animals (protection of natural nests and the creation of artificial ones), hanging feeders in the winter, hanging shelters for daytime and wintering bats. The negative impact on the biotopes of Feofaniya from the side of recreants is somewhat leveled at the expense of educational work with vacationers. The most relevant propaganda work is aimed at educating correct behavior in nature, explaining the need to protect all plant and animal species, their biotopes, and explaining the consequences of disturbing the balance of sustainable development of ecosystems.

The American mink (Neovison vison), native to North America, is a controversial invasive species in many European countries, including Poland. Mitochondrial DNA data (concatenated MT-CYTB and MT-COI sequences) were used to investigate the genetic diversity of native, introduced, and ranch populations of this species. Phylogenetic analysis revealed two major clades including individuals from the ranch, feral, and wild populations. This supports the theory of occurrence of two mitochondrial lineages in the native range of American mink assigned to eastern and western part of North America. The genetic structure in the invasive range was probably the result of the diverse origins of the released specimens and the rapid expansion and encounters of the introduced populations. Spatial mixing of both North American lineages in Polish feral populations may lead to higher levels of genetic diversity in introduced populations, despite some evidence of a founder effect as one of the main factors influencing their diversity.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiological agent of COVID-19 , is considered a pathogen with animal origin, mainly transmitted human to human. It has been experimentally and naturally demonstrated that several animals can be infected by SARS-CoV-2. There are strong evidences that minks are highly susceptible to SARS-CoV-2 infection, since several cases of human to mink infection have been reported, and it has been suggested mink to human infection exists, which so far it is the most reliable example of a zoonotic event of COVID-19 . However, all these cases reported are form mink farms, with the exception of one case in the USA in which the virus was detected in a mink located in the wild, but it was demonstrated that the animal was infected on a fur farm. In the present work, we have detected SARS-CoV-2 RNA in two wild American minks (Neovison vison) in Valencian Community (Eastern Spain) during invasive species trapping campaigns. The animals were trapped from areas known for harbouring self-sustained populations, far away from the nearest fur farm. SARS-CoV-2 RNA was detected in mesenteric lymph nodes samples by RT-PCR. A partial region of the Spike protein gene was amplified and sequence obtaining a 397 nt size sequence. Phylogenetic analysis shown that both sequences were identical to the consensus variant SARS CoV-2 sequence (from Wuhan). This research describes the first infection report of a true wild American mink not related to infected fur farms or direct contact with humans, which is believed to be the first example of wild animals in which SARS-CoV-2 has been detected.

Background Recurring escapes or deliberate releases and subsequent infiltration or establishment of feral populations by individuals from fur farms have been commonly noted since the beginning of fur industry expansion. Once animals have invaded ecosystems adjacent to source farms escapees can change the demography of the feral populations through hybridization, outbreeding depression, competition and spreading of various pathogens which can decimate wild populations. In our study, we aimed to assess spread of Aleutian mink disease virus (AMDV) in the feral population of American mink (Neovison vison) in Iceland. The additional objective was to elucidate whether basic morpho-anatomical parameters (i.e., Fulton’s condition factor or spleen to body weight ratio) might be used as a preliminary indicator of AMDV infection. Methods American mink (n = 164) were captured by professional hunters in 8 regions of Iceland. The detection of AMDV in the spleen of male and female individuals was based on PCR amplification of an NS1 gene fragment. Results We confirmed AMDV presence in 23.8% (n = 39) of collected samples with no significant difference in infection rate between males and females. Additionally, we revealed that the prevalence of virus in the feral population was higher closer to fur farms. However, the countrywide prevalence and direction of AMDV distribution needs to be further investigated. Comparison of condition indices in non-infected and infected animals showed significant deterioration of body and spleen parameters in the latter group. Therefore, the application of basic measurements of the American mink may be used to evaluate the health status of individuals in terms of pathogen infection. Conclusions The study shed a new light on prevalence and distribution of AMDV in the feral population of American mink in Iceland and the results might be successfully applied to develop models to infer dynamics of various pathogens, even those latently transmitted by disease-free animals.

This experiment investigated the effect of vitamin A supplementation on growth, serum biochemical parameters, jejunum morphology and the microbial community in male growing-furring mink. Thirty healthy male mink were randomly assigned to three treatment groups, with 10 mink per group. Each mink was housed in an individual cage. The mink in the three groups were fed diets supplemented with vitamin A acetate at dosages of 0 (CON), 20,000 (LVitA) and 1,280,000 IU/kg (HVitA) of basal diet. A 7-day pretest period preceded a formal test period of 45 days. The results show that 20,000 IU/kg vitamin A increased the ADG, serum T-AOC and GSH-Px activities, villus height and villus height/crypt depth ratio (p &lt, 0.05). The mRNA expression levels of IL-22, Occludin and ZO-1 in the jejunum of mink were significantly higher in the LVitA group than those in the CON and HVitA groups (p &lt, 0.05). Vitamin A supplementation increased the diversity of jejunum bacteria, decreased the ratio of Firmicutes to Bacteroidetes and increased the relative abundance of Akkermansia, uncultured bacterium f Muribaculaceae, Allobaculum, Lachnospiraceae NK4A136 group, Rummeliibacillus and Parasutterella. The comparison of potential functions also showed enrichment of glycan biosynthesis and metabolism, transport and catabolism pathways in the vitamin A supplementation groups compared with the CON group. In conclusion, these results indicate that dietary vitamin A supplementation could mediate host growth by improving intestinal development, immunity and the relative abundance of the intestinal microbiota.

Trichinellosis is a zoonosis with worldwide distribution. Several hosts have been recognized around the world; however, there is a lack of knowledge of the role of feral mammals in Chile in its transmission. Herein, we tested muscle samples from 555 individuals among American minks (Neovison vison Schreber, 1777. n = 100) and several myomorph rodent species (Muridae and Cricetidae. n = 455) from southern Chile by artificial digestion to detect Trichinella larvae and identified the larvae at the species level through molecular analyses. Rodents were captured in agricultural and wild protected areas of several administrative regions (hereafter: region), while minks were captured in agricultural areas of the Los Rios region. Trichinella spiralis larvae were detected in a synanthropic black rat (0.24%) of the Nuble region and in seven minks (7%) trapped in agricultural areas of the Los Rios region. The present results suggest that T. spiralis circulation is restricted to synanthropic rodents and minks living in agricultural areas where the parasite circulates among domesticated pigs. This study represents the first record of T. spiralis in a mustelid mammal in South America, increasing the number of feral species that could participate in the reservoir.

Canids and scavenger birds were shown to act as definitive hosts of numerous Sarcocystis species using members of the Cervidae family as an intermediate host, whereas definitive hosts spreading closely related S. elongata, S. entzerothi, S. japonica, S. matsuoae, S. rangiferi, S. truncata, S. silva and S. tarandi remain unknown. In the current study, the intestine samples of 40 American minks (Neovison vison) were molecularly tested for the presence of the above-mentioned Sarcocystis spp. Species-specific PCR of cytochrome c oxidase subunit I (cox1) fragments and subsequent sequencing revealed the presence of sporocysts/oocysts of five species, S. elongata (n=2), S. entzerothi (n=10), S. japonica (n=4), S. silva (n=13) and S. truncata (n=21) in the analysed samples. Sarcocystis infection was confirmed in 32/40 (80%) examined samples. In addition, half of the infected animals (50%) were infected with multiple Sarcocystis species suggesting that American minks had access to meat of different deer species, such as roe deer, red deer and sika deer. This causes concern about compliance of hunters and game processing companies with game waste management rules. Further research on the involvement of mustelids in the transmission of various Sarcocystis spp. from different geographical locations is needed.

The feral mink population in Denmark consists of two groups of animals: mink born in the wild and mink that have recently escaped from farms. The aims of this study were to: (1) estimate the reproductive performance and mortality of the Danish mink born in the wild (wild-born) and mink escaped from farms (captive-born), (2) discuss the likelihood of a self-sustaining population of wild-born mink in Denmark, and (3) model the relationship between the pulp cavity width and the age of mink. During 2018, 247 wild caught mink were sent for necropsy at the Danish National Veterinary Institute. Based on body length, 112 were determined as captive-born and 96 as wild-born. The mean litter size &plusmn, SE of wild-born females was 7.6 &plusmn, 0.9 (range: 5&ndash, 11 kits) and for captive-born females 5.9 &plusmn, 0.9 (range: 1&ndash, 10 kits). The relationship between age (in months) of mink and pulp cavity width was highly significant. Individuals with a pulp cavity width of &gt, 35% were younger than one year. Based on fecundity, the turnover of the mink population was estimated to be 66%, and the yearly mortality was estimated at 69%. Hence, the population is slightly declining. In conclusion, a feral reproducing mink population in Denmark persists without a continuous influx of captive-born mink from farms.

Using PCR, we evaluated the presence of parvoviruses and Mycoplasma spp. in 123 American mink (Neovison vison), an introduced invasive carnivore in Chile. Our results showed all analyzed animals were negative for both pathogen groups. We cannot completely dismiss their presence, but if present, their prevalence should be lower than 2%.

Trichinellosis is a worldwide disease that is considered emerging and neglected. Several hosts have been recognized around the world, however, there is a lack of knowledge of the role of free-range mammals in Chile. Herein we examined 555 individuals among American minks (Neovison vison Schreber, 1777. n = 100) and several myomorph rodent species (Muridae and Cricetidae. n = 455) from southern Chile with artificial digestion and molecular analyses. Rodents were captured in agricultural and wild protected areas, while minks were captured in mixed agricultural and unprotected wild areas. One rat (0.24%) in the Ñuble Administrative Region and seven minks (8.2%) in the Los Ríos Region were infected with Trichinella spiralis Owen, 1835. Our results suggest that native rodents are of low or null importance in the reservoir of T. spiralis in Chile. Conversely, our results suggest that T. spiralis is circulating in minks, but with low prevalence. Further studies are needed to assess whether minks are maintaining T. spiralis life cycle or are a dead-end host of this parasite in Chile. This study represents the first record of T. spiralis in a mustelid mammal in South America, increasing the number of free-range species that could participate in the reservoir.

Within only one year after the first detection of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), nearly 100 million infections were reported in the human population globally, with more than two million fatal cases. While SARS-CoV-2 most likely originated from a natural wildlife reservoir, neither the immediate viral precursor nor the reservoir or intermediate hosts have been identified conclusively. Due to its zoonotic origin, SARS-CoV-2 may also be relevant to animals. Thus, to evaluate the host range of the virus and to assess the risk to act as potential animal reservoir, a large number of different animal species were experimentally infected with SARS-CoV-2 or monitored in the field in the last months. In this review, we provide an update on studies describing permissive and resistant animal species. Using a scoring system based on viral genome detection subsequent to SARS-CoV-2 inoculation, seroconversion, the development of clinical signs and transmission to conspecifics or humans, the susceptibility of diverse animal species was classified on a semi-quantitative scale. While major livestock species such as pigs, cattle and poultry are mostly resistant, companion animals appear moderately susceptible, while several model animal species used in research, including several Cricetidae species and non-human primates, are highly susceptible to SARS-CoV-2 infection. By natural infections, it became obvious that American minks (Neovison vison) in fur farms, e.g., in the Netherlands and Denmark are highly susceptible resulting in local epidemics in these animals.

COVID-19 is one of the most important pandemics in recent history. It is an emerging infectious disease, probably of animal origin. Several domesticated and non-domesticated animals are naturally susceptible to SARS-CoV-2 infection, including Mustelidae, of which mink is the first species identified to suffer from this infection. We report herein the detection of the SARS-CoV-2 RNA in lymph node tissue from two feral American mink (Neovison vison) trapped in the wild in the Valencian Community (Eastern Spain) during invasive species trapping campaigns. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causal agent of COVID-19, is considered a pathogen of animal origin that is mainly transmitted from human to human. Several animal species can be naturally or experimentally infected by SARS-CoV-2, with compelling evidence that mink is highly susceptible to SARS-CoV-2 infection. Human-to-mink infection cases have been reported and there are also suggestions that mink-to-human infection occurs. Mink infections have been reported to date only on fur farms, except for one infected free- ranging wild mink near a Utah (USA) fur farm, which suggests a transmission pathway from farms to wild mink. We now report the detection of SARS-CoV-2 in 2 of 13 feral dark brown American mink (Neovison vison) trapped in the Valencian Community (Eastern Spain), during an invasive species trapping campaign. They were trapped in riverbeds in sparsely inhabited rural areas known to harbor self-sustained feral mink populations. The closest fur farm is about 20 km away. SARS-CoV-2 RNA was detected by two-step RT-PCR in these animals' mesenteric lymph nodes and was confirmed by sequencing a 397-nucleotide amplified region of the S gene, yielding identical sequences in both animals. A molecular phylogenetic analysis was run on this sequence, which was found to correspond to the consensus SARS-CoV-2 sequence from Wuhan. Our findings appear to represent the first example of SARS-CoV-2 acquired in the wild by feral mink in self-sustained populations.

Predation is the most important factor limiting Northern Hemisphere duck nest survival. While most avian nest predators take only eggs, mammalian predators also pose mortality risks to incubating ducks. Partial depredation of duck clutches elevates subsequent nest desertion probability, especially where eggshells provide evidence of the depredationevent. Avian predators tend to consume egg contents at the nest, which may not intrinsically pose a risk to hens, but leave egg remains. This begs the question: does primary avian depredation of duck eggs actively facilitate nest visits by secondary mammalian predators, with potential survival consequences for the remaining clutch, but also sittinghens? We created 335 artificial duck nests in Finland and Denmark during 2017-2019 and monitored them for seven days using wildlife cameras to test whether initial avian predators breaking the eggs facilitated visits by secondary mammalian predators in various duck breeding habitats. Visitation rates of mammalian predators likely to take duck hens increased significantly after avian egg depredation events that involved egg breakage, although rates differed between habitats. Most common mammalian nest visitors at nests depredated by avian predators were red fox (Vulpes vulpes), followed by two alien species, raccoon dog (Nyctereutes procyonoides) and American mink (Neovison vison). Although we should be prudent about extrapolating conclusions from artificial experiment to real duck nests, our results strongly suggest inter-guild facilitation between avian and mammalian predators at duck nest sites. We suggest that by breaking the eggs, avian predators may offer olfactory, visual or other cues for secondary predators. Nest visits by mammalian predators could potentially increase egg depredation risk, but also elevate mortality risks for incubating females, dependent upon prevailing predator guilds.

In the UK, the native European otter (Lutra lutra) and invasive American mink (Neovison vison) have experienced concurrent declines and expansions. Currently, the otter is recovering from persecution and waterway pollution, whereas the mink is in decline due to population control and probable interspecific interaction with the otter. We explored the potential of DNA metabarcoding for investigating diet and niche partitioning between these mustelids. Otter spraints (n = 171) and mink scats (n = 19) collected from three sites (Malham Tarn, River Hull and River Glaven) in northern and eastern England were screened for vertebrates using high-throughput sequencing. Otter diet mainly comprised aquatic fishes (81.0%) and amphibians (12.7%), whereas mink diet predominantly consisted of terrestrial birds (55.9%) and mammals (39.6%). The mink used a lower proportion (20%) of available prey (n = 40 taxa) than the otter and low niche overlap (0.267) was observed between these mustelids. Prey taxon richness of mink scats was lower than otter spraints and beta diversity of prey communities was driven by taxon turnover (i.e. the otter and mink consumed different prey taxa). Considering otter diet only, prey taxon richness was higher in spraints from the River Hull catchment and beta diversity of prey communities was driven by taxon turnover (i.e. the otter consumed different prey taxa at each site). Studies using morphological faecal analysis may misidentify the predator as well as prey items. Faecal DNA metabarcoding can resolve these issues and provide more accurate and detailed dietary information. When scaled up across multiple habitat types, DNA metabarcoding should greatly improve future understanding of resource use and niche overlap between the otter and mink.

The feral mink population in Denmark consists of two groups of animals; mink born in the wild and mink that have recently escaped from farms. The aims of this study are; 1) to estimate the reproduction and mortality of wild-born and captive-born mink and 2) to estimate the age of mink based on the width of pulp cavity (% of tooth width) in the canine teeth. During 2018, 247 wild caught mink were sent for necropsy at the Danish National Veterinary Institute. Of these mink, 112 were determined as captive-born and 96 were determined wild-born. The mean litter size ± SE of wild-born females was 7.6 ± 0.9 (range: 5-11 kits) and for captive-born females 5.9 ± 0.9 (range: 1-10 kits). The best fitting regression line for mink age (in months) based on pulp width was y=0.42x2-11.52x+104.7, R² = 0.77, p< 0.0001. Individuals with a pulp cavity width

Background Both of American mink (Neovison vison) and wild rat (Rattus norvegicus) is considered reservoir hosts carrying many endoparasites. Trichinella is a successful parasitic nematode including nine species and three genotypes with a worldwide distribution. However, little is known about the prevalence of Trichinella infection in mink (Neovison vison) and rat (Rattus norvegicus) in China.Methods In total, 289 muscle samples of minks and 102 rat carcasses were collected between April 2017 and December 2019 in Weihai city of Shandong province, China. The food of minks including chicken skeleton and mashed marine products was also collected at 3 batches. All the samples were used to examine for the appearance of Trichinella by the pooled artificial HCl-pepsin digestion method. The isolates from minks and rats were identified as T. spiralis by multiplex PCR. Then, the phylogenetic tree was constructed based on the sequences of 5S rDNA inter-gene spacer regions.Results Muscle larvae were detected in 20 out of 289 minks (6.92%) and in 2 of 102 wild rats (1.96%), respectively. The intensity of Trichinella in mink samples was ranged from 0.025 to 0.815 lpg, while the larval burden in rats was 0.17 lpg. The isolates from minks and rats were identified as T. spiralis by multiplex PCR. Sequence analysis revealed a 100% identical alignment of the 5S rDNA inter-gene spacer regions from the two isolates. The phylogenetic tree confirmed the two isolates from minks and rats belonging to T. spiralis based on analysis of the 5S rDNA inter-gene spacer sequence.Conclusions The present study represents the first report of T. spiralis infection in American mink (Neovison vison) and wild rat (Rattus norvegicus) from Shandong province, China. The farmed minks would be vulnerable to Trichinella infection through exposure to the wild rats. The prevalence of T. spiralis in wild rats may raise a public health concern for the potential zoonotic risk for the domestic animals.

Simple Summary Invasive species are widely recognized to negatively affect native species through both direct and indirect interactions. When diet overlap between the native and invasive species increases, their competitive interaction is expected to increase too. This in turn may lead to displacement of one of the species. However, the specific mechanisms of the diet displacement are still unclear. In this study, we analysed the diet and diet overlap between the critically endangered European mink and the invasive American mink during the invasion process of the latter species by means of stable isotope analyses. We found a significant diet overlap between the native and invasive mink when they co-occur, an important individual variation of diet, and no significant change of diet of the native species in response to the arrival of the invasive mink. These results suggest significant competitive pressure imposed on the native European mink by the invasive American mink. As such, urgent implementation of control measures of invasive species is needed to ensure the viability and conservation of endangered European mink populations. Abstract The pressure elicited by invasive species on native species significantly increases with the increase of the overlap of their ecological niches. Still, the specific mechanisms of the trophic displacement of native species during the invasion process are unclear. The effects of the invasive American mink (Neovison vison) on the critically endangered European mink (Mustela lutreola) was assessed by analyses of diet and niche overlap during the invasion process. To do this, the isotopic composition (δ13C and δ15N) of both species of mink and their four main types of prey was analysed. Significant trophic overlap between the native European mink and invasive American mink was found when they coexisted in sympatry. Furthermore, both mink species were characterised by significant individual variation in diet and no obvious change in diet of the native species in response to the arrival of the introduced species was observed. High niche overlap registered between both species in sympatry with no displacement in diet of the native mink in response to the arrival of the invasive mink is expected to have important consequences for the viability and conservation of the native mink populations, as it suggests high competitive pressure.