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The American mink Neovison vison is an invasive carnivore which may significantly affect populations of the water vole Arvicola amphibius. However, its impact on this rodent species depends on the abundance, dispersion and configuration of the habitats suitable for water voles and their accessibility for the mink. Using live-trapping, we studied the water vole and American mink populations inhabiting midfield ponds located in the vicinity of a large lake. In the same area, the mink diet was described after collecting and analysing scats. During four spring seasons, the water vole density gradually increased and no population peaks or crashes were observed. The maximum recorded density was 9.0 individuals/1 km of pond shoreline. Water voles displayed high year-to-year population turnover: less than 5% of the marked individuals were recaptured in the following year. In April–July, the exchange of individuals in the population during one-month periods was also high and usually exceeded 50%. Water vole remains were found in mink scats in all seasons, and the highest overall percentage biomass of water vole in mink diet for a two-months period reached 52.2% in May–June 2012. The results of our study show that at small water bodies adjacent to a large lake, the water vole population may withstand the impact of the invasive American mink.

Genetic polymorphism and the population genetic structure of ranch (maintained at the fur farms) and feral American minks inhabiting the geographical region of the Caspian–Baltic watershed of the European part of Russia were investigated using eight microsatellite loci. A relatively high level of genetic variability of these forms with a tendency of higher polymorphism in the feral population was revealed. Between ranch and feral minks, not considerable, but highly statistically significant genetic differences were established. The gene pool of free-ranging minks does not bear traces of recent hybridization with ranch forms. The feral population is characterized by a distinct genetic structure and a pronounced pattern of genetic isolation by distance. Statistically significant differences in the genetic structure of local groups of animals inhabiting different regions of the studied territory are determined by the recent history of naturalization of the invasive species, including deliberate introduction in the northeast of the studied region and colonization of other parts of the Caspian–Baltic watershed by the descendants of the fur farm escapees.

The aim of the study was to analyse the sex ratio of American mink litters in relation to dam's age, gestation length, and time interval between the first and second mating. The observations were carried out on a mink farm located in northern Poland. The analysis involved litters of 207 females, aged 1 (n=107) and 2 years (n=100), which successfully raised all the born kits. The sex of the offspring was identified on weaning. The kits were assigned to groups according to their dam's gestation length, mating date, and first-to-second mating interval. It was found that female kits quantitatively predominated over male offspring. Longer pregnancies, delayed mating time, and greater interval between the first and second mating was accompanied by a higher number of female births in relation to male births.

A survey was conducted on 30 Danish mink farms from April to October 2016 to determine the prevalence and species of Eimeria in Danish farmed mink. In total, 2.6% of mink faecal samples (108/4140) were positive for Eimeria vison-like oocysts by microscopy, with 24.8% (78/315) of mink being positive at least once during the study period. Morphological analysis of sporulated oocysts (n = 20) identified Eimeria vison-like oocysts measuring 21.0 × 13.8 μm with a length/width (L/W) ratio of 1.5. Phylogenetic analysis of 18S rRNA sequences (1221 bp) from three positive mink indicated that Eimeria vison-like shared the highest genetic similarity to Eimeria sp. ex Apodemus agrarius from a Striped field mouse (A. agrarius) from the Czech Republic (99.6%). Analysis of a shorter region of 18S (531 bp) revealed that the E. vison-like genotype sequences grouped in the same clade and shared 97.7% similarity with E. furonis. At the cytochrome c oxidase subunit I (COI) locus, mink-derived sequences were not available from GenBank and phylogenetic analysis placed the novel E. vison-like in a clade with E. cf. ictidea (99.4% similarity) from a black footed ferret (Mustela nigripes) from Canada.

Stereotypic behaviours (SBs) are common in confined animals including captive Carnivora, which display diverse forms of SB: often whole-body movements (e.g. pacing), but also head-only movements (e.g. head twirling) and ‘scrabbling’ (scratching at enclosure boundaries). Although often pooled together, emerging evidence indicates that SBs are heterogeneous, suggesting that subtypes differ in their causes, triggers, and consequently treatments. In mink, a model carnivore, scrabbling seems to be elicited by neighbouring conspecifics. We tested this hypothesis via three studies of 32 males (individually caged in rows and separated by solid partitions). Study 1 investigated whether neighbour proximity affects the location of any SBs, and Study 2, whether removing neighbours reduces any SBs. Results revealed that although mink typically avoided proximity to their neighbours, scrabbling was uniquely directed towards neighbours who were close to the shared cage partition. It was also the only SB significantly elevated by having all-male neighbours, and reduced by removing neighbours. Study 3 then investigated whether environmental enrichment, a standard SB treatment, would reduce or abolish different SBs equally, to assess whether scrabbling is simply easier to alleviate than other SBs. Enrichment reduced all SB subtypes, but logistic regressions revealed that the odds of complete abolition were higher for whole-body and head-only SBs than for scrabbling. Overall, these naturally solitary carnivores thus seem to avoid conspecific proximity, but they specifically direct their stereotypic scrabbling at neighbours; and their scrabbling is reduced by neighbour removal, while their whole-body and head-only SBs are instead better alleviated with enrichment. Understanding that carnivore SBs are heterogeneous in their triggers and most effective treatments may help zoos, breeding centres and mink farms improve the design of their enclosures and the efficacy of their enrichments.

Carnivores usually act as definitive hosts of Sarcocystis species. However, the number of reports on sarcocyst formation in musculature of predators is on the increase. In the present study, muscle samples of 68 mustelids collected in Lithuania were examined for sarcocysts of Sarcocystis species. Sarcocysts were detected in diaphragm, tongue and limb muscles of ten animals (14.7%) but were not discovered in the heart. Based on 18S rDNA, 28S rDNA, cox1 and ITS1 sequence analysis, Sarcocystis lutrae was identified in three American minks (Neovison vison), two beech martens (Martes foina), three Eurasian badgers (Meles meles), one Eurasian otter (Lutra lutra) and one European polecat (Mustela putorius). The intraspecific variability of this Sarcocystis species was determined only in ITS1 region. Based on the phylogenetic analysis, no clear separation of S. lutrae by intermediate hosts or geographical locations was established. This paper represents the first identification of S. lutrae in the American mink, the beech marten and the European polecat. Current results indicate that S. lutrae is a common species in the muscles of various European mustelids.

Mammalian carnivores have adapted to successfully occupy a wide range of environments spanning tropical to polar ecosystems. Some species, however, have evolved in ways that constrain their ability to thrive in extreme environmental conditions. For example many members of the Family Mustelidae are vulnerable to extreme temperatures resulting from their tubular body shape. The American mink (Neovison vison) likely faces these temperature constraints, being a smaller-bodied mustelid that ranges over a large portion of North America. Mink are largely understudied in its native range with knowledge being particularly sparse with respect to winter ecology. During 2011–2012 we conducted winter telemetry on seven adult mink and used resource selection function models to assess habitat selection patterns while considering spatial extent and gender. We found that at a larger extent, the animals' use of habitat was strongly linked to riparian features, whereas this effect was less noticeable at a finer scale. The larger males selected more lakeshore habitat, whereas the smaller females generally were near smaller streams with both selecting for beaver modified habitat. While we recognize the limited sample size in our study, we speculate that this spatial separation could be linked to higher energetic costs for females to forage aquatically in winter because of their smaller body size. This may make females more sensitive to competition from other forest carnivores (e.g. American marten) as well as impacts from resource development activities.

The American mink (Neovison vison) was introduced in Europe for fur farming in the 1920s and feral populations were formed due to escapes or intentional releases to the wild thereafter. Nowadays, the species is widely distributed across much of the continent, and is considered the main cause of extinction of the European mink (Mustela lutreola). In Spain, the first populations of the American mink were formed in the 1980s and since then a continuous expansion in their range has been observed. We describe the expansion process of the American mink based on reports of its distribution in the literature, focusing particularly on its increasing overlap with the distribution of the native, endangered European mink. Over the 27 years (1985–2012), the distribution area of non-native mink in Spain increased by 17 times, with an average annual increment of 16.5% and no significant variation among populations. By 2012, a quarter of continental Spain was occupied by the American mink and its presence was confirmed in one-third of the distribution area of the European mink. The status of native mink has worsened drastically in Spain over the last years and urgent conservation measures are required to stop further spread of the American mink.

To evaluate health effects associated with consumption of fish contaminated with polychlorinated biphenyls (PCBs) from the upper Hudson River, farm-raised mink were fed diets containing fish collected from the river. Endpoints assessed included adult reproductive performance, offspring growth and mortality, and organ mass and pathology of adults and their offspring. Scat samples were collected from adult males at the time of necropsy and from adult females just prior to whelping. Scat samples were analyzed for PCBs, polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs). The present study provides the results of these analyses and compares ∑PCB and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) toxic equivalent (TEQ) concentrations in scat with dietary and hepatic concentrations associated with effects reported previously. Dry weight concentrations of ∑PCBs and ∑TEQs in scat generally increased with dietary concentration and reflected corresponding increases in hepatic concentrations of ∑PCBs and ∑TEQs. Maternal concentrations of ∑PCBs in scat expressed on a dry, wet, and lipid weight basis predicted to result in 50% kit mortality (LC50) were 1.0, 0.30, and 12 μg ∑PCBs/g. Concentrations of ∑PCBs in scat expressed on a dry, wet, and lipid weight basis predicted to result in 50% incidence of a previously reported jaw lesion (EC50) were 1.7, 0.48, and 24 μg ∑PCBs/g in adult females and 2.5, 0.87, and 19 μg ∑PCBs/g in adult males. Environ Toxicol Chem 2018;37:563-575. © 2017 SETAC.

Background Infectious skin disorders are not uncommon in mink. Such disorders are important as they have a negative impact on animal health and welfare as well as on the quality and value of the fur. This study presents the isolation of Arcanobacterium phocae from mink with severe skin lesions and other pathological conditions, and from wild seals and otters. Results In 2015, A. phocae was isolated for the first time in Denmark from outbreaks of dermatitis in mink farms. The outbreaks affected at least 12 farms. Originating from these 12 farms, 23 animals cultured positive for A. phocae. The main clinical findings were necrotizing pododermatitis or dermatitis located to other body sites, such as the lumbar and cervical regions. A. phocae could be isolated from skin lesions and in nine animals also from liver, spleen and lung, indicating a systemic spread. The bacterium was also, for the first time in Denmark, detected in dead seals (n = 9) (lungs, throat or wounds) and otters (n = 2) (throat and foot). Conclusions An infectious skin disorder in mink associated with A. phocae has started to occur in Danish farmed mink. The origin of the infection has not been identified and it is still not clear what the pathogenesis or the port of entry for A. phocae infections are. Electronic supplementary material The online version of this article (doi:10.1186/s13028-017-0342-8) contains supplementary material, which is available to authorized users.

This study examines the occurrence of invasive American mink Neovison vison and native water voles Arvicola amphibius along the shorelines of eutrophic lakes and at small midfield ponds in the Mazurian Lakeland, north-east (NE) Poland. The main hypothesis tested in this study is that built-up areas and small midfield ponds are avoided by mink; therefore, they can serve as refuges that protect water voles from mink predation. Floating rafts were used to monitor mink and water vole distribution. Mink presence was negatively associated with urbanization at lake shorelines and midfield ponds, and these two characteristics positively correlated with occurrence of water voles in the study area. The probability of occurrence of water voles was significantly lower at sites where mink occurred. The occupancy rates for mink at lakes and at midfield ponds were higher in autumn than in spring and conversely the occupancy rates for water voles were higher in spring and lower in autumn. Our study shows that within a postglacial landscape, urban areas and midfield ponds distant from lakes are avoided by the American mink and thus these areas may function as refuge habitats for water voles and may maintain populations of this rodent at the landscape scale despite the presence of mink.

Farmed mink (Neovison vison) is one of the most important fur-bearing species worldwide, and coat colour is a crucial qualitative characteristic that contributes to the economic value of the fur. To identify additional genes that may play important roles in coat colour regulation, Illumina/Solexa high-throughput sequencing technology was used to catalogue the global gene expression profiles in mink skin with two different coat colours (black and white). RNA-seq analysis indicated that a total of 12,557 genes were differentially expressed in black versus white minks, with 3,530 genes up-regulated and 9,027 genes down-regulated in black minks. Significant differences were not observed in the expression of MC1R and TYR between the two different coat colours, and the expression of ASIP was not detected in the mink skin of either coat colour. The expression levels of KITLG, LEF1, DCT, TYRP1, PMEL, Myo5a, Rab27a and SLC7A11 were validated by qRT-PCR, and the results were consistent with RNA-seq analysis. This study provides several candidate genes that may be associated with the development of two coat colours in mink skin. These results will expand our understanding of the complex molecular mechanisms underlying skin physiology and melanogenesis in mink and will provide a foundation for future studies.

Introduction: The aim of the study was to investigate the mechanical and geometric properties as well as bone tissue and mineral density of long bones in mink dams exposed to deoxynivalenol (DON) since one day after mating, throughout gestation (ca. 46 d) and lactation to pelt harvesting. Material and Methods: Thirty clinically healthy multiparous minks (Neovison vison) of the standard dark brown type were used. After the mating, the minks were randomly assigned into two equal groups: nontreated control group and DON group fed wheat contaminated naturally with DON at a concentration of 1.1 mg·kg-1of feed. Results: The final body weight and weight and length of the femur did not differ between the groups. However, DON contamination decreased mechanical endurance of the femur. Furthermore, DON reduced the mean relative wall thickness and vertical wall thickness of the femur, while vertical cortical index, midshaft volume, and cross-sectional moment of inertia increased. Finally, DON contamination did not alter bone tissue density, bone mineral density, or bone mineral content, but decreased the values of all investigated structural and material properties. Conclusion: DON at applied concentration probably intensified the process of endosteal resorption, which was the main reason for bone wall thinning and the weakening of the whole bone.

Stereotypic behaviours (SBs) are sometimes assumed homogeneous, despite their diverse morphologies, as if sharing a common aetiology. However, if different SB forms are instead heterogeneous, they may have different causes, potentially impacting how best to prevent or manage them. We therefore conducted two exploratory studies with mink ( Neovison vison ) to investigate whether ‘loco’ SBs (locomotor forms like pacing, and ‘stationary’ forms like head-bobbing) are homogeneous or heterogeneous, and to corroborate previous findings that ‘scrabbling’ (stereotypic scratching at cage walls) is distinct from loco SBs. We assessed correlations between their time-budgets (Studies 1 and 2), followed young mink as they aged (Study 2), and used chi-square goodness-of-fit tests to explore whether some SB forms co-occur within bouts more or less frequently than expected by chance (Study 2). Co-occurrence in bouts and positive correlations between different SB forms would indicate homogeneity and perhaps shared causal factors. Conversely, SB forms appearing on their own in bouts and/or showing absent or negative correlations with other forms would indicate heterogeneity. Study 1 demonstrated negative correlations between scrabbling and most loco SB forms ( p 0.05), but positive correlations between most loco forms ( p 0.05). Study 2 improved upon Study 1’s methods with a new sample of mink, a refined ethogram, and the collection of longitudinal data and data on multiform sequences during SB bouts. Scrabbling, again, negatively correlated with several loco SB forms ( p 0.05). It was also likely to occur in bouts without any other SB form. Moreover, within the loco group, the two subtypes of route-tracing (‘nestbox pacing’ and pacing) positively correlated ( p 0.05), and ‘nestbox pacing’ often occurred in bouts with pacing. Stationary SBs, however, appeared heterogeneous: head-twirling and head-bobbing tended to positively correlate with each other ( p 0.10), but not other forms, and to appear in individual bouts; while whole-body bobbing and head-weaving positively correlated with route-tracing ( p 0.10), and they also co-occurred. Overall, results confirmed that scrabbling is distinct from other SBs. Loco SBs, however, appeared either homogeneous (Study 1) or heterogeneous (Study 2), depending on the ethogram. We conclude that a SB ethogram precisely based on morphology (e.g., whole-body versus head-based SBs) is most likely to reveal underlying heterogeneities; that future researchers should validate our new proposed mink SB subcategories, ‘whole-body’ and ‘head-based’; and that our methods could usefully be applied to other species to categorise their SBs.

Many studies have evaluated wildlife passage effectiveness, but few have explored how accurately passage activity can be modeled. I created a habitat suitability index (HSI) model for American mink (Neovison vison) using a geographic information system with 17 wildlife passages located in Quebec, Canada as validation for the model. I addressed how well HSI modeling using constrained habitat data could determine mink passage activity and tested model sensitivity to different parameterizations. Uncertainty analysis revealed that the HSI model was sensitive to extreme changes in factor weights and scale. I used a generalized linear model to test how well the constrained HSI model explained the variability in passage activity (counts). For the HSI model (and all alternatives) the HSI scores were negatively associated with passage use. The predictive power of all models greatly improved after including aspects related to passage construction, with the pseudo-R2 increasing by 64–73%. These findings suggest that the constrained HSI models are a poor predicator of passage activity for mink, but wildlife passage characteristics are highly predictive. Transportation agencies would benefit from the ability to make informed planning decisions; however, greater care is required to determine passage suitability. The proper implementation of these tools requires knowledge of habitat preferences and how movement is influenced by the wildlife passages themselves. © 2017 The Wildlife Society.

A small population of otter and mink coexist on the Isle of Salvora, off the coast of Galicia, a region in northwest Spain. The aim of this study was to analyse the feeding habits of both species (taxa and type of prey) and their degree of trophic overlap. In order to analyse which habitat features best define otter and mink trophic preferences, fish preys were defined according to three criteria: substrate preference, position in the water column, and tidal zones. A total of 178 otter spraints and 158 mink scats were collected and analysed between May and October 2007. The relative frequency of occurrence and the biomass of each taxon were calculated. Mink consume mainly rabbits in spring, seagulls in summer, and rodents and shrews in autumn. The frequency of rabbits and gulls in mink diet was related to the abundance of both prey on the island. Otters were basically feeding upon fish throughout the study period. Their main prey was garfish (pelagic fish) during spring and summer, and Bleniidae and Gobiidae (benthic fish of rocky bottom pools) in autumn. These fishes are also consumed by mink during late summer, when the diet overlap between both species is higher (August diet overlap of 43.5 %, mean diet overlap of 16.4 %).

Feed quality is generally assumed to affect health status in animal production. In previous studies, the feed producer has been found to affect the occurrence of gastrointestinal disease and antimicrobial use in Mink (Neovison vison). Mink are fed with moist, freshly produced feed, based on perishable ingredients. The objective of this study was to investigate the potential effect of specific feed parameters on antimicrobial use on herd level. The study was cross-sectional, including 1472 mink herds, responsible for 97% of oral antimicrobials prescribed for Danish mink during the study period, 2012–2014. Data were obtained from the national veterinary prescription database (VetStat), Kopenhagen Fur database, and the Voluntary Feed Control (Mink producers Organization). All feed batches subject to feed control were included. A multi-variable variance analysis was carried out analysing the effect of the feed parameters total volatile nitrogen, dry matter, crude protein and fat; total bacterial count (21 °C), and counts of sulphite producing bacteria (21 °C), Clostridium spp., faecal cocci (FC) (44 °C), yeast, and mould; presence of Salmonella spp. and Clostridium perfringens (dichotome). Three outcome variables were applied: prescription of oral antimicrobial on herd level within time slots of 3, 5 or 7 days after feeding of an included batch. Two binomial models were developed, adjusting for significant effects (p

Changes in distribution of six mammal species, viz. Procyon lotor, Nyctereutes procyonoides, Neovison vison, Cervus nippon, Dama dama, Ovis aries musimon in SW Poland (42000 km2), since their introduction till 2008, have been analyzed. A rough estimate of their numbers is also provided for seven regions in SW Poland (Silesia). Detailed maps of distribution of the American mink and fallow deer in SW Poland during 2004–2008 are also presented. The alien ungulates, as long-established species in SW Poland, are not considered as particularly destructive to indigenous flora and fauna. They are not invasive, and have never been regarded as such. On the other hand, the alien carnivores are regarded in SW Poland as destructive to the indigenous fauna. Counter-measures for the rapidly increasing carnivores are proposed.

This article contains the results of morphological studies of liver in the American mink (Neovison vison) by atomic force microscopy. We have performed the visualization of hepatocytes, principal cell structures, and intercellular contacts. In contrast to studies on the liver structure by electron microscopy, it is found that hepatocytes have an uneven structure and polygonal shape with a thick central part (with nucleus) and oblong polar parts. The nucleus of the hepatocytes has a round or oval shape, uneven surface, and notable karyolemma. The nucleolus is located on the surface of the nucleus and has a pyramidal shape. The texture of the cytoplasm is unevenly nodular, and the edges of intercellular contacts are uneven. Our data on the nanostructure of liver can be used in measuring of morphological parameters of healthy organs in minks and for the comparative diagnostics of hepatic pathologies.

Morphometric measurements were used to classify 11 mustelid dentaries from Snake Creek Burial Cave (SCBC), a late Pleistocene to early Holocene—aged paleontological locality in eastern Nevada, that were undifferentiated between Mustela nigripes (black-footed ferret) and Neovison vison (American mink) due to their similar size and morphology. We, therefore, classified the SCBC fossils using 10 linear measurements of the dentary using extant M. nigripes and N. vison as proxy. Discriminant function and principal component analyses grouped the 11 unknown SCBC specimens within extant M. nigripes exclusively. Confirmation of M. nigripes at SCBC is significant because Cynomys spp. (their primary prey source today) have not been found at this site or other nearby Great Basin localities. Occurrence of this now-endangered taxon among the SCBC paleofauna and review of additional localities lacking Cynomys suggest that several geographically and temporally discrete prehistoric M. nigripes populations were sustained by other small mammal taxa. If this inference is true, facilitating dietary diversity in reintroduced M. nigripes populations could improve the species' resilience to future adversities, including anthropogenic climate change.

The invasive American mink (Neovison vison) preys on native fauna. The pilot phase of the Hebridean Mink Project (HMP) ran from 2001–2006 at a cost of £1.6 million and successfully removed the species from 1100 km2 of the southern islands of the Hebridean Archipelago, the Uists. Mink were also controlled in South Harris to prevent reinvasion. 532 mink were removed, and no further animals were caught or recorded in the eradication area in the last six months of the project. The entire archipelago is now being trapped using techniques developed from the pilot phase. The programme used an adaptive approach, learning as the project proceeded. The lessons learned were also applied to two other scenarios. These included the Isle of Mull, where with limited resources, trapping is carried out by volunteers, and the development of a national management plan in Ireland, where the species is widespread and farmed. The strategies and techniques developed in the Hebrides were modified to fit these differing ...

Farmed American mink (Neovison vison (Schreber, 1777)) pose a risk to biodiversity owing to escape and release from farms. Feral mink may affect native species in locations where American mink are not endemic, such as Europe. In contrast, escaping domestic mink may hybridize with wild mink in North America, leading to introgression of domestic traits via hybrid-mediated gene flow. We tested this idea in eastern Canada, which has a history of mink farming. We sampled known domestic and free-ranging mink, and profiled 508 individuals at 15 microsatellite loci. We found that 33% of free-ranging mink were either escaped domestic individuals, domestic–wild hybrids, or were introgressed to domestic or wild parental groups. The greatest prevalence of free-ranging domestic, hybrid, or introgressed mink (59%) occurred in Nova Scotia, which also had the most mink farms. Historic (1980s or earlier) mink sampled from museums had higher allelic richness and private allelic richness than contemporary wild mink. Domestic mink are artificially selected for traits desired by farmers, and as such, introgression with wild mink may lead to a loss of local adaptation. Our findings demonstrate that continued escape and release of mink could pose risks to the maintenance of genetic integrity in wild mink.

Summary The specimens collected from American mink (Neovison vison) and European polecat (Mustela putorius) in Lithuania were morphologically identified as Isthmiophora melis (Schrank, 1788) Lühe, 1909 and were molecularly characterized through sequencing of partial 18S rDNA, 28S rDNA, ITS1- 5.8S-ITS2 region, and ND1. Relations of I. melis to other species of the genus Isthmiophora Lühe 1909 were discussed. According to ITS1 and ND1 sequences the closest species to I. melis is Isthmiophora hortensis (Asada, 1926).

Disease in mink clinically characterized by abortion and increased mortality among pregnant female mink on 28 Danish farms was observed during April and May 2015. Most of these farms suffered extensive disease problems, including a significant increase in the number of mated females without litters. Pathological, microbiological and molecular biological methods were applied to investigate the cause of disease. Necropsies of animals found dead revealed fragile and partially dissolved (liquefying) uterine tissue, with the presence of Gram positive rod-shaped bacteria. These slow growing bacteria were isolated by anaerobic culturing and identified as Clostridium limosum by both MALDI-TOF mass spectrometry analysis and 16S rRNA gene sequencing. All the performed tests for relevant differential diagnoses were negative. Foodborne disease was indicated because all the affected farms were served by the same feed factory. A specific PCR-based analysis was developed for positive identification of C. limosum and used to screen archived feed samples from the implicated feed factory. Both C. limosum 16S rRNA genes and C. limosum collagenase genes were identified in both mixed feed and more specifically in raw chicken carcass used as one of the components in the mixed feed, which was therefore identified as the most likely source of contamination. Based on the results of this investigation it is concluded that C. limosum can be associated with abortion and increased mortality in pregnant mink females and it is consequently recommended that raw materials contaminated with C. limosum should be avoided in mink feed, in particular during the whelping season.

BackgroundIndividual differences of mink, including color type, are speculated to affect the course of wound healing, thereby impacting wound assessment and management on the farms, as well as the assessment of wounds in forensic cases. In this study, we examined the effect of color type on early wound healing in farmed mink. Full thickness excisional wounds (2 × 2 cm) were made on the back in 18 mink of the color types Brown, Silverblue and Blue Iris. Gross and microscopic pathology of the wounds was evaluated 2 days post-wounding together with degree of wound size reduction, presence of bacteria and blood analyses.ResultsPathological examination on day 2 showed the greatest mean wound size reduction in Brown mink (11.0%) followed by Blue Iris (7.9%) and Silverblue (1.6%). Bacteria were cultured from all wounds, and predominantly Staphylococcus species were recovered in mixed or pure culture. Histopathology from day 2 wounds showed a scab overlying necrotic wound edges, which were separated from underlying vital tissue by a demarcation zone rich in polymorphonuclear leukocytes. Fibroblasts and plump endothelial cells were more numerous in the deeper tissues. Complete blood count parameters were within normal ranges in most cases, however, the mink showed mildly to markedly decreased hematocrit and six mink of the color types Silverblue and Blue Iris showed moderately elevated numbers of circulating segmented neutrophils on day 2. There was a marked increase in concentration of serum amyloid A from day 0 to day 2 in all color types.ConclusionsWe have described differences in early wound healing between mink of the color types Brown, Silverblue and Blue Iris by use of an experimental wound model in farmed mink. The most pronounced difference pertained to the degree of wound size reduction which was greatest in Brown mink, followed by Blue Iris and Silverblue, respectively.

Mercury (Hg) is a pollutant of global concern. Sentinel species such as river otter (Lontra canadensis) and mink (Neovison vison) are often used to monitor environmental concentrations in freshwater ecosystems. Tissue total Hg (THg) concentrations are frequently used as biomarkers of exposure. However, there is no comprehensive model relating Hg tissue concentrations in different tissues, making interstudy comparisons challenging. Our objective was to establish conversion factors relating fur, brain, liver, kidney, and muscle THg concentrations using mean concentrations and standard errors reported in the literature. We used data from more than 6000 samples, pooled across 16 studies and 96 sampling sites in North America and Europe. Sixteen regressions were derived for the river otter and mink models, which were statistically significant at a 95% confidence interval and yielded high explained variances. The models were validated using an external data set of individually measured THg tissue concentrations. The validated conversions were used to evaluate the current fur Hg screening guidelines of 20 µg/g and 30 µg/g. At both of these fur concentrations, brain concentrations are of concern for altering brain neurochemistry. We suggest a more conservative fur Hg screening guideline of 15 µg/g to protect sensitive furbearers. The conversion factors can be used to predict internal organ THg concentrations from fur measurements, eliminating the need for invasive tissue sampling. Environ Toxicol Chem 2017;36:2377–2384. © 2017 SETAC

The aim of this study was to investigate the activity patterns of American mink (Neovison vison). Twenty mink from a commercial mink farm were housed in a free-range enclosure (290 m2) at the age of 13 weeks. In the enclosure, the mink were offered 20 nest boxes (animal-to-nest-box ratio: 1:1), food ad libitum, and 3 kinds of water basins. The activity rhythms and the use of the nest boxes were assessed by an automatic registration device that recorded the amount of time spent inside or outside the nest box or in the entrance tunnel for each individual mink over a period of 18 weeks between July and December. In addition to analyzing the mink's daily and seasonal activity patterns, we sought to detect any social preferences or preferences for individual nest boxes. Results showed that the mink had crepuscular activity patterns with 2 activity peaks during dusk and dawn and that the former shifted when the daylight period shortened. Throughout the experiment, the activity time spent outside the nest boxes declined with increasing age and decreasing ambient temperature. In addition, the mink showed a preference for nest boxes that faced the feeding lots and not the water basins. During sleep and rest periods, the mink spent high amounts of time using the nest boxes in company. Furthermore, the mink structured their own habitat by using certain nest boxes for sleeping and others as latrine boxes. Small differences between male and female mink existed in their activity (i.e., time spent inside or outside nest boxes) but not in their preference for certain nest boxes or other individuals. Based on our results, any environmental enrichment item should be presented all day long, so each mink has the opportunity to use them individually during their main activity times mostly at dusk and dawn, and their daily handling should be adjusted to this rhythm. A mink-to-nest-box ratio of 1:1 does not seem necessary as juvenile mink often slept in groups of 2 or more animals in 1 nest box. Furthermore, the animals should be given the opportunity to distinguish between a sleeping and a latrine area.

This study was designed to investigate the possibility of total replacement of conventional diet by formulated experimental feed in farmed mink during gestation. Ninety female mink (Neovison vison) were randomly assigned to three groups: control group was fed conventional diet with normal (36%, C) protein level composed of fresh or frozen animal by-products and extruded corn. Formulated experimental diets contained animal meals, vegetable ingredients and fat, with normal (36%, E1) or high (44%, E2) protein level, and were mixed with water prior to administration. Nutrient digestibility, nitrogen (N)-balance and reproductive performance were determined to compare the effect of diets fed to female mink during gestation. Mink fed both experimental diets had lower nutrient digestibility than the control. Higher barren females, decreased birth survival rate and birth weight were noted for the two experimental groups, especially diet E1 with normal dietary protein, indicating impaired reproduction performance, but signs of improvement were seen in the experimental group with high protein level (44%, E2).

Invasive alien species can have widespread negative effects on native biodiversity. We investigated the prospects of engaging hunters in large-scale collaborative efforts to control non-native mink Neovison vison populations in Norway. We invited members of the Norwegian Association of Hunters and Anglers to complete an online questionnaire to ascertain their support for conservation and their level of effort to remove mink, in the context of hunting motivations and bounty payments. The general interest in mink control programmes was low but participants perceived the mink to be of conservation concern. Bounty payments influenced mink catches, with hunters who received payments catching a mean of 4.70 more individuals per hunter than those who did not receive payments (P < 0.001). Mink hunters who preferred to hunt alone and had no preference for hunting locally reportedly caught on average 1.87 more mink per hunter than those who preferred to hunt in company (P < 0.001). The majority of hunters preferred government-led programmes (47%), and investment in bounty programmes (52%) was their main recommendation to improve mink hunting. Hunters can be a valuable component of a mink removal task force and could decrease the likelihood of recolonization of mink in the buffer areas of core conservation target areas.

It has been known that selective breeding of animals for behavior associated with domestication changes a variety of physiological traits including response to stress and hypothalamo–pituitary–adrenocortical system activity. The aim of our research was to find association between behavioral type and differential leukocyte counts as an indicator of homeostasis activity. We used farm-raised 5-month-old minks ( Neovison vison ) that had been selective bred for 17 generations on the basis of behavior toward human. After selection, minks were divided into the following groups: aggressive (from −4 to −1), "domestic" (from +1 to +5). Blood leukocytes were analyzed in 5-month-old minks (n = 105) of different behavior lines: aggressive (−1, −2), "domestic" (+1 and from +3 to +5), fearful, and minks never subjected to selective breeding (control). We found strong effects of selection for behavior of minks on differential blood leukocyte count. There were differences between behavior types in differential leukocyte counts. Neutrophils and eosinophils were the leukocyte types the most sensitive to selection for behavior. The counts of eosinophils in peripheral blood in "domestic" (+3, +5) minks were higher than in control and aggressive (−2) minks. The percentage of neutrophils was higher in the most aggressive minks (−2) in comparison to "domestic" minks. We have concluded that differences found in leukocytes profile are the result of neuroendocrine system modification.

Analysis of the fragment of mtDNA D-loop (369 bp, n = 48) in wild and domestic American minks harvested in Caspian-Baltic watershed in the European part of Russia reveals a relatively high level of genetic polymorphism for introduced specimens. The values of haplotype and nucleotide polymorphism are correspondent to the level found in populations of the species inhabiting Eastern Europe (Poland). The tendency of differentiation of haplogroups is noted against the background of weak geographical or breeding structure of populations. Observed patterns of polymorphism are probably connected with peculiarities of introduction history as well as with the pool of initial DNA set of ancestors introduced in Eurasia. The domesticated form of the American mink does not differ from wild populations of the species on the basis of the used DNA marker. In wild populations of the species located at a short distance from a mink farm, haplotypes typical of domesticated minks are found.

Lake Glubokoe (Moscow oblast, Russia) is one of the most investigated water bodies of Europe. We detected new parasite species for the ecosystem of the lake (alien for territory of Europe): coccidian Goussia obstinata (in invasive alien fish Perccottus glenii) and copepod Neoergasilus japonicus (on aboriginal ruff Gymnocephalus cernuus). The given coccidian is host-specific for P. glenii and was introduced in the lake together with its host. Participation of P. glenii in circulation of recorded heteroxenous helminthes (Isthmiophora melis, Azygia lucii, and Raphidascaris acus) was revealed. This is confirmed by the data on trophic links of their obligatory definitive hosts (American mink Neovison vison and northern pike Esox lucius) with P. glenii in Lake Glubokoe.

Amdoparvovirus is a newly defined parvoviral genus that contains four species (Carnivore amdoparvovirus 1–4), including the well-known Aleutian mink disease virus (AMDV). Amdoparvoviruses cause an immune-associated and often lethal wasting syndrome in Mustelidae and Caninae hosts. In this study, we molecularly investigated amdoparvoviruses detected in 44 striped skunks (Mephitis mephitis) found dead in and around Vancouver, British Columbia, Canada. Some of the animals exhibited pathological changes compatible with amdoparvovirus-associated disease. The nearly complete genomic sequence was obtained for seven different strains and our analyses show how this virus, which we named skunk amdoparvovirus (SKAV), should be classified as a separate species within the genus (proposed Carnivore amdoparvovirus 5). We detected co-infections, recombinant genomes, at least three separate viral lineages, and preliminary evidence for geographic segregation of lineages. Furthermore, we proved that similar viruses, only partially characterized in previous studies and labeled as AMDV, circulate in skunks from other distant areas of North America (Ontario and California) and found evidence for spillover events in mink (Neovison vison). Although SKAVs are capable of causing disease in infected animals, a high proportion of sub-clinical infections has been observed, suggesting these animals might act as asymptomatic carriers and pose a threat to wild and captive carnivores. Finally, we highlight the need for more specific diagnostic tests and further molecular investigations to clarify the epidemiology and host- and geographical distributions of amdoparvoviruses in terrestrial carnivores, especially because the whole spectrum of viral diversity in this group is likely still unknown.

The existence of play, a form of behaviour without obvious benefits to survival or reproduction, is a long-standing ethological mystery. Experiments in which socially deprived juvenile male mammals develop into sexually incompetent adults, along with widespread sexual dimorphism in rough-and-tumble play (R&T), suggest that R&T may prepare juvenile males for adult sexual behaviour. To test this hypothesis, we conducted a longitudinal study of American mink, Neovison vison, on two farms, with two cohorts each. For males (N = 121), we predicted that individuals with the highest frequencies of rough-and-tumble play as juveniles (10–20 weeks old) would, as adults, show shorter latencies to bite females' necks and to begin copulating, and copulate for longer durations. On one farm, we conducted a pilot study of females (N = 10) as a preliminary test of the hypothesis that R&T also prepares females for adult sexual behaviour. Here, our predictions were the opposite of those for males, since abilities to limit the number or duration of copulations could allow females to exercise pre- or postcopulatory mate choice. In total, we observed 1669 male–female encounters and 1004 separate copulations. As predicted, frequent juvenile R&T predicted long-lasting copulations in adult males and longer latencies to copulate in adult females. This was true specifically of rough-and-tumble play itself, independently of general activity levels and, among a subset of 32 males reared in environmentally enriched housing, also independently of solitary object play. To our knowledge, this is the first demonstration that juvenile rough-and-tumble play predicts adult sexual behaviour in any species. Further research is required to test whether our results for females can be replicated, and, importantly, to determine whether play truly has a causal role in either of these correlational relationships.

Despite the fact, that the American mink (Neovison vison) is one of the most intensively economically exploited and problematic, from the ecological point of view, fur-bearing animal, it remains one of the least studied livestock species. It can be proven by the fact, that the research on one of the key hormones, which has systemic effects, that is the growth hormone, are rather poorly advanced. The purpose of this review is to present the summary and the critical analysis of the current state of knowledge on the topic of the growth hormone in the American mink, its biological function, production in physiological conditions, regulation of secretion and transduction of the hormone’s signal. The article contains also an up to date information on the Amrican mink growth growth hormone gene and its protein product.

The American mink Neovison vison in Great Britain is an invasive alien species, with significant impacts on native prey species. There have been suggestions that populations of mink in Britain have declined since the 1990s. Three nationwide data sets include data on mink distribution and abundance. Scat surveys and the National Game Bag Census suggest population declines, but the latter does not take account of survey effort (which may also have declined) and the former is misleading because there is evidence that mink change their marking behaviour in the presence of otters Lutra lutra. National Biodiversity Network data suggest an increase in mink numbers, but this can be explained by a concomitant increase in mammal recording. Although intra‐guild competition between invasive mink and native otters is likely, there is no evidence that otters have caused a decline in mink numbers. There is little information on the impact of disease, or exposure to rodenticides, on wild mink – both warrant further attention. Eradication efforts can have an impact on mink populations, but currently neither implementation nor monitoring is sufficient to generate effects throughout Great Britain or to assess the impact of cumulative local and regional efforts. We conclude that it is not possible, on the basis of currently available data for Great Britain, to ascertain the status of mink or assess the underlying trend in their population. We stress the importance of collaboration, coordination, and record keeping (and sharing) in future, proper interpretation of existing data, and the use of alternative data sources. We call for greater, and better, effort in both mink management and monitoring of management in Great Britain.

More than 55 million mink skins were produced globally in 2017. As a consequence, a large number of people are employed in mink production worldwide. In Denmark, farmed mink were found to constitute a reservoir of methicillin-resistant Staphylococcus aureus (MRSA) clonal complex (CC) 398 and 6000 mink farm workers in Denmark are potentially exposed to LA-MRSA CC398. The study aim was to elucidate the source of LA-MRSA CC398 in mink farms and to investigate possible transmission to humans. In total, 161 LA-MRSA CC398 isolates from mink (n = 65), mink feed (n = 16) and humans (n = 80) with reported contact to mink, were whole-genome sequenced and compared to 183 LA-MRSA CC398 isolates from Danish pigs and an international collection of 89 S. aureus CC398 isolates. Most of the mink-associated isolates clustered within the predominant LA-MRSA CC398 lineages circulating in the Danish pig production, supporting that pigs are a source of LA-MRSA CC398 in mink feed, mink, and mink farmers.