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The American mink has spread widely beyond its native North America due to the activities of fur traders. The mink is an extremely adaptable, generalist predator. Over two continents, the American mink is associated with problems in the conservation of local species because of their impact on both prey and competitors. Here, we review the impact of American mink on native species, stemming from over a decade of research, and concentrate on two examples: the impact of American mink on the water vole in Britain and on the European mink in Eastern Europe. While the near extinction of the water vole in Britain and that of the European mink in Eastern Europe are largely due to predation and interspecific aggression, respectively, both may have been affected by a multitude of factors acting synergistically. Terns, and other seabirds, are impacted by mink predation; the effect on riparian bird species is less clear but may potentially be high. Emerging principles, supported by preliminary evidence, sugg...

Along the upper stream of the Aragon River, a team of Spanish conservation biologists will release 10 or 12 captive-bred European minks ( Mustela lutreola ) next week. The hope is that they will start a new population and help save the European mink, a critically endangered species from extinction. Protecting the furry, dark-brown carnivore requires killing its main competitor, the American mink ( Neovison vison ), brought to Europe a century ago by fur farmers; the Spanish team is betting on an elaborate system of floating traps to capture American minks. Elsewhere in Europe, too, reintroduced European minks can only live in such ecological safe spaces.

Although it is well documented that the gut microbiota plays an important role inhealth and disease in mammalian species, this area has been poorly studied among carnivorous animals, especially within the mustelidae family. The gastrointestinal tract of carnivores is characterized by its short length and fast transit time, as compared to omnivores and herbivores, which is due to the low level of inherent fermentation.Mink represents an example of this, which have a GI tract only four times the length of the body and a transit time of approximately 4–5 hr. In this study, we used high-throughput 16S rRNA gene sequencing to explore the resident gut microbiota of the mink in terms of intra-and interindividual diversity. We report, for the first time, that the mucosa-associated bacterial community within the colon is diverse and dissimilar from the community found in the feed. We found large interindividual differences in bacterial composition between individual animals being dominated generally by the phylum Firmicutes, but in some cases also Proteobacteria or Fusobacteria. The bacterial load and community structure within the mucus was not severely impacted by 3 days of fasting, which implies that a resident and stable microbiota is hosted by these animals. Although it is well documented that the gut microbiota plays an important role in health and disease in mammalian species, this area has been poorly studied among carnivorous animals, especially within the mustelidae family. The gastrointestinal tract of carnivores is characterized by its short length and fast transit time, as compared to omnivores and herbivores, which is due to the low level of inherent fermentation. Mink represents an example of this, which have a GI tract only four times the length of the body and a transit time of approximately 4–5 hr. In this study, we used high-throughput 16S rRNA gene sequencing to explore the resident gut microbiota of the mink in terms of intra-and interindividual diversity. We report, for the first time, that the mucosa-associated bacterial community within the colon is diverse and dissimilar from the community found in the feed. We found large interindividual differences in bacterial composition between individual animals being dominated generally by the phylum Firmicutes, but in some cases also Proteobacteria or Fusobacteria. The bacterial load and community structure within the mucus was not severely impacted by 3 days of fasting, which implies that a resident and stable microbiota is hosted by these animals.

Inbreeding is an increasing problem in farmed mink, because of limited exchange of individuals between farms. In this study, genetic relatedness within seven American mink (Neovison vison) colour strains originating from 13 different mink farms in Denmark was analysed using 21 polymorphic microsatellite loci. We detected large differences in the level of relatedness (range 0.017-0.520) within colour strains. Moreover, a very strong and highly significant negative correlation between the level of relatedness and fecundity was observed (r = 0.536, P < 0.001) [Correction added after online publication on 9 March 2011: r(2) has been changed to r]. To our knowledge, this is the first time that such a correlation has been demonstrated for commercially farmed mink.

This study provides new faunistic data for helminths of mustelids in Lithuania. Twenty-five mustelids were examined for helminths: 2 pine martens ( Martes martes ), 4 stone martens ( Martes foina ), 9 American minks ( Neovison vison ) and 10 European polecats ( Mustela putorius ). Nine taxa of the parasitic worms were found: trematodes Isthmiophora melis (Schrank, 1788) and Strigea strigis (Schrank, 1788) mesocercaria, cestodes Mesocestoides lineatus Goeze, 1782 and Cestoda g. sp. and nematodes Eucoleus aerophilus (Creplin, 1839), Aonchotheca putorii (Rudolphi, 1819), Crenosoma schachmatovae Kontrimavicius, 1969, Molineus patens (Rudolphi, 1845) and Nematoda g. sp. The biggest infection parameters were detected for flukes Isthmiophora melis and Strigea strigis mesocercaria in American mink and European polecat. In most cases the distribution of helminths in populations of mustelids was aggregated (s 2 /A > 1).

The phylogenetic and taxonomic position of the American mink Neovison vison have long been unclear. In this paper, the complete mitogenome of N. vison was sequenced and characterized. The total length was 16,594 bp and typically consists of 37 genes, including 13 protein-coding genes, 2 rRNAs, 22 tRNA, a large control region (CR) and a light-strand replication origin (OL). Gene contents, locations, and arrangements were identical to those of typical vertebrate. The overall base composition is 33.6%, 25.4%, 27.8% and 13.3% for A, C, T and G, respectively, with a moderate bias on AT content (61.4%). This result is expected to provide useful molecular data and contribute to further taxonomic and phylogenetic studies of Mustelidae and Carnivora.

Balancing of macronutrient intake has only recently been demonstrated in predators. In particular, the ability to regulate carbohydrate intake is little studied in obligate carnivores, as carbohydrate is present at very low concentrations in prey animal tissue. In the present study, we determined whether American mink (Neovison vison) would compensate for dietary nutritional imbalances by foraging for complementary macronutrients (protein, lipid and carbohydrate) when subsequently given a dietary choice. We used three food pairings, within which two macronutrients differed relative to each other (high v. low concentration), while the third was kept at a constant level. The mink were first restricted to a single nutritionally imbalanced food for 7 d and then given a free choice to feed from the same food or a nutritionally complementary food for three consecutive days. When restricted to nutritionally imbalanced foods, the mink were willing to overingest protein only to a certain level (‘ceiling’). When subsequently given a choice, the mink compensated for the period of nutritional imbalance by selecting the nutritionally complementary food in the food choice pairing. Notably, this rebalancing occurred for all the three macronutrients, including carbohydrate, which is particularly interesting as carbohydrate is not a major macronutrient for obligate carnivores in nature. However, there was also a ceiling to carbohydrate intake, as has been demonstrated previously in domestic cats. The results of the present study show that mink regulate their intake of all the three macronutrients within limits imposed by ceilings on protein and carbohydrate intake and that they will compensate for a period of nutritional imbalance by subsequently selecting nutritionally complementary foods.

The aim of the study was to analyze the effects of the first mating date, age and color variety on the conception rates in farm mink. We analyzed female mink reproductive performance in 492 Sapphire and 463 Standard Black females over 3 or 4 years. The analysis included the number of inefficient matings, the interval between the first inefficient mating and the efficient mating (copulation) and the conception rates. The results show a significant effect of female's age and color variety on the conception rates. The youngest, yearling females of either color needed a higher number of matings per conception, as compared to older, 2- and 3-year-old females. Black females demonstrated a higher number of inefficient matings (1.066), as compared with Sapphires (0.730). Yearling females were most often mated from 1 to 10 March, and older females from 11 to 20 March. Older females achieved better conception rates than the yearlings. Dates between 11 and 25 March proved to be the optimum for the first mating, since the highest conception rates were observed if the females had mated during this period.

We observed the morphology of the lingual papillae (filiform, conical, fungiform, and vallate papillae, and lateral organ) and their connective tissue cores (CTCs) in the American mink (Neovison vison) using light and scanning electron microscopy. Filiform papillae were distributed on the apex linguae and rostral regions of the corpus linguae. Conical papillae were distributed over the caudal region and absent in the radix linguae. Numerous ridges were present in the radix linguae. Four to six vallate papillae were situated at the border between the corpus and radix linguae. Instead of foliate papillae, a pair of lateral organs was situated on the caudal edge of the corpus. The epithelial surface of each filiform papilla consisted of a single main process and 10–12 accessory processes. Notably, filiform papillae in the apex linguae exhibited morphological variation, and some were dome-like and lacked processes. In contrast, filiform papillae on the rostral part were not variable, were extended to a sharp tip, were associated with an eosinophilic stratum corneum, and lacked nuclei. The CTCs of the filiform papillae consisted of a main core and slender accessory cores surrounding a concavity. Those in the apex linguae were similar in appearance and consisted of main and adjacent accessory cores. The fungiform papillae had a dome-like epithelial surface and their CTCs were columnar, with upper concavities and flanges. The simplified lingual morphology of the American mink, particularly in the filiform papillae in the apex linguae, may be influenced by its diet and semiaquatic lifestyle.

��������� � �� ���������� Summary Mapping of QTL affecting fur quality traits (guard hair length, guard hair thickness, density of wool, surface of the fur and quality) and skin length was performed in a three-generation mink population (F2 design). In the parental generation, Nordic Brown mink were crossed reciprocally with American Black short nap mink. In all, 1082 mink encompassing three generations were used for the analyses. The mink were genotyped for 104 microsatellites covering all 14 autosomes. The QTL analyses were performed by least-square regression implemented in GRIDQTL software. Genetic and phenotypic correlations and heritabilities were estimated using the average information-restricted maximum-likelihood method. Evidence was found for QTL affecting fur quality traits on nine autosomes. QTL were detected for guard hair thickness on chromosomes 1, 2, 3, 6 and 13; for guard hair length on chromosomes 2, 3 and 6; for wool density on chromosomes 6 and 13; for surface on chromosomes 7, 12 and 13; for quality on chromosomes 6, 7, 11 and 13; and for skin length on chromosomes 7 and 9. Proximity of locations of QTL for guard hair length, guard hair thickness and for wool density and quality suggests that some of the traits are in part under the influence of the same genes. Traits under the influence of QTL at close or identical positions also were traits that were strongly genotypically correlated. Based on the results of correlation analyses, the most important single traits influencing the quality were found to be density of wool, guard hair thickness and appearance of the surface.

Background Rapid body fat mobilization, obesity, and an inadequate supply of n-3 polyunsaturated fatty acids (PUFA) have been suggested to play roles in the etiology of fatty liver in the American mink (Neovison vison). This study examined the effects of feeding intensity and dietary fat source on fatty liver induced by fasting. In a multi-factorial design, 3 different fat sources (herring oil, rich in n-3 PUFA, soya oil, rich in n-6 PUFA, and canola oil, rich in n-9 monounsaturated fatty acids) were fed to mink at a low and high feeding intensity for 10 weeks, followed by an overnight or a 5-day fasting treatment to induce fatty liver. Results Fasting led to the development of fatty liver with increased severity in the mink fed at the high feeding intensity. The herring oil diet, high in long-chain n-3 PUFA, was found to decrease the severity of fatty liver in the mink at the high feeding intensity. Conclusion Preventing excessive weight gain and increasing dietary intake of n-3 long-chain PUFA may help prevent excessive lipid accumulation during prolonged periods of fasting or inappetence by promoting hepatic fatty acid oxidation.

BackgroundSince the recommendations on group housing of mink (Neovison vison) were adopted by the Council of Europe in 1999, it has become common in mink production in Europe. Group housing is advantageous from a production perspective, but can lead to aggression between animals and thus raises a welfare issue. Bite marks on the animals are an indicator of this aggressive behaviour and thus selection against frequency of bite marks should reduce aggression and improve animal welfare. Bite marks on one individual reflect the aggression of its group members, which means that the number of bite marks carried by one individual depends on the behaviour of other individuals and that it may have a genetic basis. Thus, for a successful breeding strategy it could be crucial to consider both direct (DGE) and indirect (IGE) genetic effects on this trait. However, to date no study has investigated the genetic basis of bite marks in mink.Result and discussion: A model that included DGE and IGE fitted the data significantly better than a model with DGE only, and IGE contributed a substantial proportion of the heritable variation available for response to selection. In the model with IGE, the total heritable variation expressed as the proportion of phenotypic variance (T2) was six times greater than classical heritability (h2). For instance, for total bite marks, T2 was equal to 0.61, while h2 was equal to 0.10. The genetic correlation between direct and indirect effects ranged from 0.55 for neck bite marks to 0.99 for tail bite marks. This positive correlation suggests that mink have a tendency to fight in a reciprocal way (giving and receiving bites) and thus, a genotype that confers a tendency to bite other individuals can also cause its bearer to receive more bites.ConclusionBoth direct and indirect genetic effects contribute to variation in number of bite marks in group-housed mink. Thus, a genetic selection design that includes both direct genetic and indirect genetic effects could reduce the frequency of bite marks and probably aggression behaviour in group-housed mink.

Remarkable adaptations in the Carnivora have evolved as a way of dealing with feeding competition, accen- tuating hypocarnivorous or hypercarnivorous morphotypes. The Carnivora is a highly successful order with 47 living species in South America. Their history in South America is recent, and includes few lineages that arrived before the Pana- manian bridge was completed (procyonids), and others that arrived later (felids, mephitids). Here, we evaluated the trophic segregation of small carnivorans ( Conepatus chinga , Galictus cuja , Lontra provocax , Lyncodon patagonicus , and the intro- duced Neovison vison ) from southern South America, using a geometric morphometric approach, i.e., Principal Component and Canonical Variate Analysis, to study shape variations and t -tests to study size variation. We also performed Canonical Phylogenetic Ordination to study the association between shape, size, diet, and phylogeny. We identified C. chinga as the most hypocarnivorous member of the guild, G. cuja , L. patagonicus ,and N. vison as hypercarnivores, with L. provocax in an intermediate position. Semiaquatic habits seg- regate Lontra provocax , and partially N. vison ,fromother species. Significant differences in size were observed between all species pairs, except C. chinga and N. vison . Phylogeny accounts for a very important part of morphological variance, with cladogenetic events between mustelids and mephitids responsible for almost 55 % of it. The small carnivoran guild of southern South America is represented by species adapted to different feeding strategies, with C. chinga and L. provocax preying mainly on invertebrates, G. cuja and L. patagonicus specifically on small vertebrates, and the non-native N. vison with a highly diverse diet. Fil: Schiaffini, Mauro Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de la Patagonia "San Juan Bosco". Facultad de Ciencias Naturales - Sede Esquel. Laboratorio de Investigaciones en Evolución y Biodiversidad; Argentina Fil: Prevosti, Francisco Juan. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina. Universidad Nacional de Luján; Argentina

Summary Low protein provision in utero and post-partum may induce metabolic disorders in adulthood. Studies in mink have mainly focused on short-term consequences of low protein provision in utero whereas the long-term responses to low protein (LP) provision in metabolically programmed mink are unknown. We investigated whether low protein provision in utero affects the long-term response to adequate (AP) or LP provision after weaning in male mink. Eighty-six male mink were exposed to low (19% of ME from CP; crude protein) or adequate (31% of ME from CP) protein provision in utero, and to LP (~20% of ME from CP) or AP (30–42% of ME from CP) provision post-weaning. Being metabolically programmed by low protein provision in utero did not affect the response to post-weaning diets. Dietary protein content in the LP feed after weaning was below requirements; evidenced by lower nitrogen retention (p

We previously reported that methylmercury (MeHg) exposure is associated with DNA hypomethylation in the brain stem of male polar bears. Here, we conveniently use archived tissues obtained from controlled laboratory exposure studies to look for evidence that MeHg can disrupt DNA methylation across taxa. Brain (cerebrum) tissues from MeHg-exposed mink (Neovison vison), chicken (Gallus gallus) and yellow perch (Perca flavescens) were analyzed for total Hg levels and global DNA methylation. Tissues from chicken and mink, but not perch, were also analyzed for DNA methyltransferase (DNMT) activity. In mink we observed significant reductions in global DNA methylation in an environmentally-relevant dietary exposure group (1 ppm MeHg), but not in a higher group (2 ppm MeHg). DNMT activity was significantly reduced in all treatment groups. In chicken or yellow perch, no statistically significant effects of MeHg were observed. Dose-dependent trends were observed in the chicken data but the direction of the change was not consistent between the two endpoints. Our results suggest that MeHg can be epigenetically active in that it has the capacity to affect DNA methylation in mammals. The variability in results across species may suggest inter-taxa differences in epigenetic responses to MeHg, or may be related to differences among the exposure scenarios used as animals were exposed to MeHg through different routes (dietary, egg injection), for different periods of time (19-89 days) and at different life stages (embryonic, juvenile, adult).

Trophic relationships between invasive species in multiply invaded ecosystems may reduce food limitation relative to more pristine ecosystems and increase resilience to control. Here, we consider whether invasive predatory American mink Neovison vison are trophically subsidized by invasive crayfish. We collated data from the literature on density and home range size of mink populations in relation to the prevalence of crayfish in the diet of mink. We then tested the hypothesis that populations of an invasive predator reach higher densities and are more resilient to lethal control when they have access to super-abundant non-native prey, even in the absence of changes in density dependence, hence compensatory capacity. We found a strong positive relationship between the proportion of crayfish in mink diet and mink population density, and a negative relationship between the proportion of crayfish in mink diet and mink home range size, with crayfish contribution to mink diet reflecting their abundance in the ecosystem. We then explored the consequence of elevated mink density by simulating a hypothetical eradication program with a constant harvest in a Ricker model. We found that mink populations were more resilient to harvest in the presence of crayfish. As a result, the simulated number of mink harvested to achieve eradication increased by 500 % in the presence of abundant crayfish if carrying capacity increased by 630 %. This led to a threefold increase in time to eradication under a constant harvest and an approximately 20-fold increase in the cumulative management cost. Our results add to evidence of inter-specific positive interactions involving invasive species, and our simple model illustrates how this increases management cost.

The welfare of an animal is ensured if it is able to fully satisfy its essential species-typical needs in all functional aspects of behaviour. In mink, stereotypies and apathy, internal and/or external injuries as well as increased susceptibility to disease have been known to occur as a result of chronic stress. The non-invasive method of analysing faecal cortisol metabolites (FCM) allows conclusions to be drawn about the stress level in the respective housing system. The objective of this study is to find out how the cortisol metabolites content in the faecal changes with increasing age of the mink under semi-natural housing conditions. Thus, 40 American mink (Neovison vison) were housed in two outdoor enclosures imitating natural conditions. Throughout the entire study (13th to 32nd week of life), faecal samples were collected to measure cortisol metabolites. No differences in FCM concentrations between the two outdoor enclosures were found. In the young mink lower, less fluctuating FCM levels were found than in older animals. After the first faecal collection in the 13th/14th week of life, the level of metabolites decreased slightly (p = 0.032; 17th/18th week). From the 22nd/23rd week onwards until the 30th/31st week, shortly before the animals were pelted, continuously increasing concentrations were then measured. Increasing FCM levels with advancing age of the animals are probably attributable to the onset of sexual maturity and/or the respective season. This has to be taken into account in future studies using this method for assessing welfare and when comparing different mink housing systems.

Wild carnivores in zoos, conservation breeding centres, and farms commonly live in relatively small, unstimulating enclosures. Under these captive conditions, in a range of species including giant pandas, black-footed ferrets, and European mink, male reproductive abilities are often poor. Such problems have long been hypothesized to be caused by these animals' housing conditions. We show for the first time that rearing under welfare-improving (i.e., highly valued and stress-reducing) environmental enrichments enhances male carnivores' copulatory performance: in mate choice competitions, enriched male American mink (Neovison vison) mated more often than non-enriched males. We screened for several potential mediators of this effect. First was physiological stress and its impact on reproductive physiology; second, stress-mediated changes in morphology and variables related to immunocompetence that could influence male attractiveness; and third, behavioural changes likely to affect social competence, particularly autistic-like excessive routine and repetition ('perseveration') as is reflected in the stereotypies common in captive animals. Consistent with physiological stress, excreted steroid metabolites revealed that non-enriched males had higher cortisol levels and lower androgen levels than enriched conspecifics. Their os penises (bacula) also tended to be less developed. Consistent with reduced attractiveness, non-enriched males were lighter, with comparatively small spleens and a trend to greater fluctuating asymmetry. Consistent with impaired social competence, non-enriched males performed more stereotypic behaviour (e. g., pacing) in their home cages. Of all these effects, the only significant predictor of copulation number was stereotypy (a trend suggesting that low bodyweights may also be influential): highly stereotypic males gained the fewest copulations. The neurophysiological changes underlying stereotypy thus handicap males sexually. We hypothesise that such males are abnormally perseverative when interacting with females. Investigating similar problems in other taxa would be worthwhile, since many vertebrates, wild and domestic, live in conditions that cause stereotypic behaviour and/or impair neurological development.

Summary American mink (Neovison vison) kits are born altricial and fully dependent 40 on maternal care, for which the kits' vocalisations appear essential. We used Auditory Brainstem Recording (ABR) to determine (1) hearing sensitivity of adult females from two breeding lines known to differ in maternal behaviour and (2) development of hearing in kits 8-52 days of age. We also studied sound production in 20 kits throughout postnatal days 1 to 44. Adult female mink had a broad hearing range from 1 kHz to above 70 kHz, with peak sensitivity (threshold of 20 dB SPL) at 8-10 kHz, and no difference in sensitivity between the two breeding lines (P>0.22) to explain the difference in maternal care. Mink kits showed no signs of hearing up to postnatal day 24. From day 30 all kits had ABRs indicative of hearing. Hearing sensitivity increased with age, but was still below the adult level at postnatal day 52. When separated from their mothers kits vocalized loudly. Until age 22 days, 90% of all kits vocalized with no significant decline with age (P=0.27). From day 25, concurrent with the start of hearing, the number of vocalizing kits decreased with age (P

Water vole Arvicola amphibius populations have recently experienced severe decline in several European countries as a consequence of both reduction in suitable habitat and the establishment of the alien predator American mink Neovison vison. We used DNA microsatellite markers to describe the genetic structure of 14 island populations of water vole off the coast of northern Norway. We looked at intra- and inter-population levels of genetic variation and examined the effect of distance among pairs of populations on genetic differentiation (isolation by distance). We found a high level of genetic differentiation (measured by FST) among populations overall as well as between all pairs of populations. The genetic differentiation between populations was positively correlated with geographic distance between them. A clustering analysis grouped individuals into 7 distinct clusters and showed the presence of 3 immigrants among them. Our results suggest a small geographic scale for evolutionary and population dynamic processes in our water vole populations. © 2013 The Authors. Ecology and Evolution published by Blackwell Publishing Ltd. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited

The American mink (Neovison vison) was introduced to Danish fur farms in the 1930s. An unknown number of mink have managed to escape these farms over the years. Today feral mink are found in the wild in most parts of Denmark. A population viability analysis (PVA) was performed using VORTEX, a stochastic population simulation software, to 1) predict the viability and potential population expansion from different sizes of founding populations of farm escapees, 2) investigate which parameters mostly affect the viability, 3) assess the effects of continuous escapes on the feral populations and how the feral populations are affected by management programs, and 4) discuss eradication strategies and their efficiency in management of the feral American mink population in Denmark. The simulations showed that juvenile mortality had the greatest effect on population viability followed by fecundity, adult mortality, and initial population size. Populations supplemented yearly by escapees all reached the carrying capacity and gained genetic variability over the years. Harvesting was modeled as the yearly number of mink caught in Denmark. Most of the simulated harvested populations crashed within few years after the first harvesting event. This indicates that the feral number of mink in Denmark is sustained due to supplements from mink farms and no true feral population exists. To manage the number of feral mink in Denmark it is essential to prevent escapees. The eradication effort would be most effective if focused on late summer and autumn when juvenile mink leave the maternal territory.

Hemorrhagic pneumonia in mink (Neovison vison) is caused by Pseudomonas aeruginosa and is an acute and fatal disease in farmed mink. Earlier work has demonstrated that some outbreaks of hemorrhagic pneumonia are caused by pathogenic strains while most outbreaks are caused by local strains. The objective of this study was to determine the genetic and geographical relationship among outbreaks of hemorrhagic pneumonia by pulsed-field gel electrophoresis typing of P. aeruginosa isolates. Furthermore, chosen isolates were typed by a commercial genotyping method based on single nucleotide polymorphisms (SNPs) and compared to a larger dataset of human and environmental origin. The bacterial isolates were obtained from diagnostic samples from 2002 to 2009 and contained 164 isolates from 95 outbreaks on 90 farms. Our results show that most outbreaks of hemorrhagic pneumonia in mink are caused by distinct strains of P. aeruginosa. We also identified related P. aeruginosa strains which, together with two prevalent but unrelated clones, caused one third of the outbreaks of hemorrhagic pneumonia supporting the sparse literature on this subject. None of the SNP typed strains were identified in a large dataset of human and environmental origin.

Background The emerging skin disease fur animal epidemic necrotic pyoderma (FENP) has been attributed to infection with Arcanobacterium phocae (ABP). The exact pathogenesis and risk factors of FENP have yet to be elucidated. Animals Three mink from each of three different mink farms (A–C) with postvaccination skin wounds at the vaccination site and six mink from an unaffected mink farm (D) that had used the same vaccine batch and vaccination site (hind leg). Methods and results All minks from farms A–C had severe necrotizing to necropurulent dermatitis where they were vaccinated intramuscularly in the hind leg. ABP was the sole bacterium cultured from six of nine wounds. Using 16S–23S rDNA intergenic spacer region and BOX-PCR, the ABP isolates from these wounds were indistinguishable from isolates originating from several cases of FENP. Conclusions and clinical importance This is the first report of FENP-like lesions at the site of vaccination, in the days following the procedure, associated with ABP. At farms with FENP vaccination, procedures should be considered carefully.

Metabolite profiling may elucidate changes in metabolic pathways under various physiological or nutritional conditions. In the present study two groups of female mink characterized as having a high (16 mink) or low (14 mink) residual feed intake were investigated during restrictive and ad libitum feeding. Blood samples were collected three times during the experimental period; during restrictive feeding, four days and three weeks after the change to ad libitum feeding. Plasma samples were subjected to liquid chromatography mass spectrometry non-targeted metabolomics. Subjecting data to principal component analysis showed that there was no grouping of the data according to the residual feed intake. In contrast, data clearly grouped according to feeding level. Identification of the metabolites responsible for this grouping showed that the plasma level of metabolites related to mobilization of energy was high during restrictive feeding, e.g. betaine, carnitine, and creatine. During ad libitum feeding the plasma level of metabolites that can be characterized as biomarkers of meat intake (creatinine, carnosine, 1- and 3 methylhistidine) was high. The plasma level of lysophosphatidylcholine species was highest after four days of ad libitum feeding suggesting a short term imbalance in the transport or metabolism of these metabolites when changing the feeding level. Metabolite profiling may elucidate changes in metabolic pathways under various physiological or nutritional conditions. In the present study two groups of female mink characterized as having a high (16 mink) or low (14 mink) residual feed intake were investigated during restrictive and ad libitum feeding. Blood samples were collected three times during the experimental period; during restrictive feeding, four days and three weeks after the change to ad libitum feeding. Plasma samples were subjected to liquid chromatography mass spectrometry non-targeted metabolomics. Subjecting data to principal component analysis showed that there was no grouping of the data according to the residual feed intake. In contrast, data clearly grouped according to feeding level. Identification of the metabolites responsible for this grouping showed that the plasma level of metabolites related to mobilization of energy was high during restrictive feeding, e.g. betaine, carnitine, and creatine. During ad libitum feeding the plasma level of metabolites that can be characterized as biomarkers of meat intake (creatinine, carnosine, 1- and 3 methylhistidine) was high. The plasma level of lysophosphatidylcholine species was highest after four days of ad libitum feeding suggesting a short term imbalance in the transport or metabolism of these metabolites when changing the feeding level.

We estimated the present population size of the Hooded Grebe Podiceps gallardoi and compared it with the population in 1985. During the breeding seasons 2009/2010 and 2010/2011 we monitored 251 lakes on the main plateaus of Santa Cruz province, southern Patagonia, Argentina, where the entire population of Hooded Grebes spends the breeding season. During 2009/2010 we monitored 131 lakes and observed 521 Hooded Grebes in 16 lakes, while during 2010/2011 we monitored 186 lakes and observed 535 individuals in 14 lakes. At both breeding seasons five lakes contained near 85% of the population. We only observed 6 breeding colonies, two in 2009/2010 and four in 2010/2011, totalling 242 nesting attempts. Nearly 90% of the nests failed during egg stage, mainly due to strong winds and depredation by American mink Neovison vison. Only 28 nests hatched chicks, but none of the young survived to independence due to low temperatures. We compared the results of our 2010/2011 survey with one conducted during 1984/1985 and detected that the population diminished by approximately 80%. This decline was observed on all but one plateau (Buenos Airesa) where most breeding attempts occurred. Our results show that at present Hooded Grebes are highly dependent on a few suitable lakes where they congregate to breed. We analyse possible causes for the decline of the population and propose conservation actions to protect this species. Fil: Roesler, Carlos Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentina Fil: Imberti, Santiago. Ambiente Sur; Argentina Fil: Casañas, Hernán. Asociación Ornitológica del Plata; Argentina Fil: Mahler, Bettina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentina Fil: Reboreda, Juan Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentina

Forty-two specimens of three tick species — Dermacentor albipictus, D. variabilis, and Ixodes cookei — were collected from a single road-killed male American mink, Neovison vison, in Leake County, Mississippi, U.S.A. The D. albipictus and I. cookei collections are new county records. This is the first report of tick collections anywhere in Mississippi from a mink.

Background Hemorrhagic pneumonia is a disease of farmed mink (Neovison vison) caused by Pseudomonas aeruginosa. The disease is highly seasonal in Danish mink with outbreaks occurring almost exclusively in the autumn. Human respiratory syncytial virus (RSV) has been shown to augment infection with P. aeruginosa in mice and to promote adhesion of P. aeruginosa to human respiratory cells. Findings We tested 50 lung specimens from mink with hemorrhagic pneumonia for bovine RSV by reverse transcriptase polymerase chain reaction (PCR) and for human RSV by a commercial real-time PCR. RSV was not found. Conclusions This study indicates that human and bovine RSV is not a major co-factor for development of hemorrhagic pneumonia in Danish mink.

The aim of the study was to determine and validate prerequisites for applying a cognitive (judgement) bias approach to assessing welfare in farmed mink (Neovison vison). We investigated discrimination ability and associative learning ability using auditory cues. The mink (n = 15 females) were divided into two groups (High, n = 8; Low, n = 7, representing the frequency of the tone they were habituated to, 18 and 2 kHz respectively) and were tested using a habituation–dishabituation procedure in experiment 1. In experiment 2 one auditory stimulus was followed by an inter-trial-interval (safe/neutral situation), whereas another auditory stimulus was followed by an aversive stimulus (air blow) before the inter-trial-interval (danger situation). We observed behaviour including latencies to show a response during both experiments. The High mink showed significant habituation in experiment 1 but the Low mink only showed habituation in experiment 2. Regardless of the frequency used (2 and 18 kHz), cues predicting the danger situation initially elicited slower responses compared to those predicting the safe situation but quickly became faster. Using auditory cues as discrimination stimuli for female farmed mink in a judgement bias approach would thus appear to be feasible. However several specific issues are to be considered in order to successfully adapt a cognitive bias approach to mink, and these are discussed.

Selection was performed for high November weight on ad libitum (AL) and restricted feeding (RF) in mink in two generations. A farm fed line (FF) was maintained as a control. The estimates of heritability for November weight were large (0.62, 0.52, and 0.73 in males and 0.68, 0.51, and 0.60 in females in the FF-, AL-, and RF-line). The results indicate that selection on AL feeding increased appetite and thereby improved feed conversion ratio while selection on RF improved feed utilization. Furthermore, the results suggest that selection for August weight produces lean mink while selection for November weight produces fat mink.

Correct managing of dam body condition during the winter period results in increased number of live born kits. So far, male body condition has not been related to male reproduction success. We therefore wanted to study whether the male body condition, visually graded using a 1 to 9 point scale, has influence on re-production results. Body condition of 6500 mink males of the brown colour type from 12 farms were scored in December, January, February and March in the winter period 2011/2012. The data will be used to seek answers for the following questions: (1) Has male body condition, or changes in body condition at specific point in time influence on mating willingness (mating willingness defined as the number of successful mating’s), percentage of barren dams and litter size? (2) Have changes in male body condition in specific periods influence on number of mating’s, percentage of barren dams and litter size? (3) What would be the optimal body condition development for mink males from December to medio March in relation to reproduction results?

Mapping of quantitative trait loci (QTL) affecting fur quality traits (guard hair length, guard hair thickness and density of wool) was performed in a 3-generation population (F2-design). In the parental generation, Nordic wild mink were crossed reciprocally with American short nap mink. Twenty one wild mink were mated to 25 short nap mink. In the F1-generation, 103 mink were mated. 934 mink were obtained in the F2-generation. The mink were genotyped using 104 microsatellites covering all 14 autosomal chromosomes. The marker spacing was approximately 11 cM. Recordings of fur quality traits were made on all genotyped mink by Kopenhagen Fur. The QTL analyses were performed by least square regression implemented in the software GridQTL. Evidence was found for QTL for the fur quality traits on eight autosomal chromosomes (LOD score >3.0). QTL were detected for guard hair thickness on chromosomes 1, 2, 3, 4, 6, 11 and 13, for guard hair length on chromosomes 2, 3 and 6 and for wool density on chromosome 6, 7 and 13. Similar locations of QTL for guard hair length and guard hair thickness on chromosomes 2, 3 and 6 suggest that these traits are in part under the influence of the same genes.

Influenza in mink (Neovison vison) is assumed to be rare, but several outbreaks have been described during recent years in Europe and the North America. In 2009, influenza A of the subtype H3N2 was detected in several Danish mink farms with respiratory symptoms. Full-genome sequencing showed that the virus was a human/swine reassortant, with the H and N gene most related to human H3N2 viruses circulating in 2005. The remaining 6 genes were most closely related to H1N2 influenza viruses circulating in Danish swine. This virus had not previously been described in swine, mink or humans. PCRs assays specifically targeting the new reassortant were developed and used to screen influenza positive samples from humans and swine in Denmark with negative results. Thus, there was no evidence that this virus had spread to humans or was circulating in Danish pigs. In 2010 and 2011, influenza virus was again diagnosed in diseased mink in a few farms. The genetic typing showed that the virus was similar to the pandemic H1N1 virus circulating in humans and swine. The H3N2 virus was not detected in 2010 and 2011. Taken together, these findings indicate that mink is highly susceptible for influenza A virus of human and swine origin and may therefore act as a potential host/reservoir for influenza A viruses.

Illegal killings of protected species may signifi- cantly affect their population status or lower recovery rates after protection. Poaching is difficult to monitor directly, hence indirect methods are required to document poaching incidences and levels. The use of shotguns inevitably results in wounding some animals that are not killed. Inefficient hunting methods may result in high annual infliction rates in game species. To reduce wounding of game species, an action plan was implemented in Denmark. Using X-ray analysis, we monitor trends in prevalence of embedded shotgun pellets in the legally hunted red fox (Vulpes vulpes) after the implementation of the action plan, and assess poaching levels of two protected species, the otter (Lutra lutra) and the badger (Meles meles )i n Denmark. Overall, 13.8% of the red foxes and 6.9% of the otters carried embedded shotgun pellets, while none were recorded in badgers. The prevalence of embedded shotgun pellets in red foxes declined from 24.9% to 8.5% from the late 1990s to the late2000s,whilenochangewasrecordedinotters.Prevalence of embedded shotgun pellets was similar in otters and red foxes collected in the late 2000s. The decline in wounded red foxes suggests that the hunting methods have changed after the action plan was implemented in Denmark. The high pro- portion of otters carrying embedded shotgun pellets shows that there is a significant poaching of this protected species in Denmark, possibly by hunters and fish farmers that cannot distinguish between otter and non-native American mink (Neovison vison).

The effects of mutations affecting the coat color on the dopamine, noradrenaline, and serotonin contents of the hypothalamus and brainstem of the farm-bred mink have been studied. The sample comprised standard (+/+) and mutant minks, including the monorecessive pastel (b/b), silver-blue (p/p), and white hedlund (h/h) and the combination double recessive sapphire (a/a p/p) and pearl (k/k p/p) ones. The dopamine content of the brainstem of the monorecessive pastel (b/b) and silver-blue (p/p) minks has been found to be higher than in standard (+/+) minks. Conversely, the homozygosity for two coat color loci in double recessive pearl minks (k/k p/p) significantly decreases the noradrenaline and serotonin contents of the hypothalamus. In addition, monorecessive and double recessive minks differ from each other in the serotonin contents of the midbrain and medulla.

Apparent total tract digestibility of major nutrients and energy was determined in a comparative study with mink (n=6), ferrets (n=6) and cats (n=2) which were fed three different diets. Apparent digestibility was determined by two methods, namely quantitative faeces collection and use of yttrium oxide as an inert dietary marker. Results achieved with the two methods agreed very well, and there were no significant differences in nutrient and energy digestibility when results generated with the two methods were compared. The recovery of the marker was close to 100%, and the correlation coefficients for AD measured by the two different methods were in most cases higher than 0.9 and highly significant. It was concluded that yttrium oxide is suitable for use as inert marker in digestibility studies with carnivorous mammals.

The objective was to validate the 13C-bicarbonate tracer technique (13CT) for estimation of the CO2 production (RCO2) and energy expenditure (EE) against ‘the golden standard’ indirect calorimetry (IC), in mink in the fed state. Six male mink were measured in a Latin-square design, simultaneously by means of 13CT and IC. A dose of NaH13CO3 was administrated orally, by subcutaneous or intra muscular injection. A zero breath sample was collected before the isotope administration. After dose administration breath samples were collected at frequent intervals for 6 h, and simultaneously the animals were measured by IC for 22 h. There was excellent agreement between results from 13CT and IC, and when using the measured factor for recovery of 13C in breath and measured RQ values, no significant differences between administration methods in estimates of RCO2 and EE were found. The 13CT was concluded to be a useful method for estimating EE, regardless of administration method, but accuracy is dependent on the estimates used for RF and RQ.

To date, 35 coat color mutations have been registered in minks. Market demands on fur, on novel coat color phases, have always been met by retention and breeding of color variations that arose by chance among captive bred individuals. Domestication has uncovered in domestic mink populations hidden genetic variability in coat color. This in turn gave clues for search and selection of new versions of coat color in mink. In other words, domestication suggests the technology appropriate for deliberately creating hither to rarely, if at all, observed novelties. To illustrate, at the Institute of Cytology and Genetics (Novosibirsk, Russia) a method has been developed for evaluation how the degree of domestic behavior may affect coat color pattern in mink. The Karelian spotted mink (S K/+) was provided as an example.

The objective of the present study was to find out at what time point standard black male mink (Neovison vison) is dying and how quickly changes in the body function can be observed. Experimental groups evaluated were: euthanasia with exhaust gases (petrol engine 4%), carbon dioxide (cylinder 80%), carbon monoxide (cylinder 2%, 4%). Brainstem auditory evoked responses (BAER), electroencephalography (EEG), electrocardiography (ECG) and respiratory rate were measured. Mean time of decline/absent BAER was 112/176, 138/183, 235/390 and 528/833 seconds after gas apply in groups, respectively. Mean time for first changes/absence of EEG was 42/86, 39/75, 55/190 and 176/426 seconds after gas apply in groups, respectively. Mean time for first changes in respiration/absent breathing was 42/217, 28/227, 144/477 and 331/901 seconds after gas application in groups, respectively. Mean time for first changes/absence of ECG was 105/292, 117/220, 215/289 and 481/682 seconds after gas apply in groups, respectively. Gases first affected the brain and brainstem which was seen as loss of EEG and BAER and thereafter respiration and heart rate ceased. A sensitivity to pain is related to consciousness and function of brain. Studied gases can be considered to primary lead to state of non-pain. They are also effective to kill the animal.

Single nucleotide polymorphisms (SNPs) are widespread sources of sequence variation in genomes and are currently applied in fields such as forensic and animal breeding genetics. Here we present how it is possible to quickly identify informative SNPs in mink based on a SNP marker panel created for the domestic dog which is phylogenetic far away from the mink. Applying the commercial available Canine SNP Genotyping BeadChip (Illumina®) to genotype 12 American mink from 4 different color strains we identified 111 SNPs in mink. Based on the 111 SNPs genetic population structure analysis showed similar levels of relatedness and genetic differentiation than previously observed using microsatellite markers in mink. We suggest strategies for applying SNP markers in practical farm management, by genotyping individuals with a few very informative genetic markers, considering genetic information that would increase the heterozygosity and have positive effects on the breeding result in mink production. Alternative applications of SNP markers for parentage analysis, individual identification and forensic identification in mink are discussed. Finally, identifying markers associated with important production traits and combined with neutral markers can combined be applied to improve genetic screening on farm levels and for developing new breeding strategies on Danish mink farms.

Digestibility was evaluated in three strict carnivore species, the ferret (Mustela putorius furo), the mink (Neovison vison) and the cat (Felis catus) in a Latin square design experiment using a homemade ferret diet, a commercial wet mink diet and a grocery store canned cat diet. Six animals per species were used, but only two cats concluded the experiment. Ferrets and mink were housed in metabolism cages whereas cats were kept in their home environment. The experiment was performed with 3-days adaptation periods followed by 4-days periods of recording of feed intake and quantitative collection of faeces. Generally, the cats digested the major nutrients better than did ferrets and mink. Ferrets and mink were mostly close in digestibility, but the mink digested fat and energy in the cat diet and protein and energy in the mink diet more poorly than the ferret. The ferret diet had the highest average digestibility whereas the cat diet had the poorest.

The present study aimed to examine if handling and training female mink on a learning task, as preparation for a cognitive bias test, had an effect on measures of their affective state. Adult female farm mink were used based on measures of approach/avoidance behaviour, and categorised as explorative (E, n=10) and fearful (F, n=10). Affective state was assessed on the basis of approach/avoidance behaviour in two contexts (stick-tests, novel object tests) and adrenocortical activity (faecal cortisol metabolites, FCM). The results showed that the F mink changed to being more explorative after handling and training for the cognitive bias test. Furthermore, the handling and training also had an effect on the E mink, but in the opposite direction. This study showed that preparing mink for a cognitive bias test had a marked effect on measures of their affective state, which has to be considered when interpreting the results from experiments using training to assess welfare.

The frequency of color aberrations in the Northern fur seal population of Commander Islands was studied. Albino, acromelanism, nonspecific piebaldness, golden, and ferret type color phases were recorded at the frequencies about 10-4. They are phenotypically similar to the same phases in farm bred sables and minks. The evolutionary sense of color aberrations in phenotypic parallelism of color mutations in the Northern Fur Seal, Mink, and Sable is discussed.

High abundance of fat stored within the liver, referred to as fatty liver disease (FLD) is frequently associated with mortalities in mink during the growth period. Studies have indicated that increased tendency for development of FLD may be one of the consequences of reduced protein contents in mink food. For studies on FLD in mink, quantitative analysis of hepatic fat in live mink using ultrasonography would be an appealing non-invasive study modality. The objective of this study was to develop and evaluate a technique for quantifying hepatic fat content in mink by ultrasonography, applying techniques previously validated for use in humans and cats. This study shows that infiltration of the mink liver with fat may be evaluated non-invasively using ultrasonography. This diagnostic imaging technique may prove useful for research in diffuse parenchymal organ disease in mink, though local hair removal prior to application of ultrasonography of organs is a considerable disadvantage in some settings.

Influenza in mink (Neovison vison) is assumed to be rare, but outbreaks have previously been reported in farmed mink. The first report was from Swedish mink farms in 1984 which was caused by influenza A virus H10N4 of avian origin. In 2009 and 2010 outbreaks of respiratory disease were seen in several Danish mink farms. In all of the farms, the clinical symptoms were upper respiratory tract symptoms with sneezing and coughing as the most dominant symptoms. Peracute deaths were seen in mink without any clinical symptoms. Influenza H3N2 was found detected by PCR in the lungs from diseased mink. The mean mortality rate was 1.20% (95% confidence intervals: 0.58–1.82) during the outbreak period. Young mink and especially males were reported to be more likely to die. The outbreak in the farms varied from two to ten weeks. During the outbreak period most farms treated all mink with antimicrobials and four of these farms used feed medication in three weeks. The farmers, however, noted that the medication had little or no effect. The most plausible way of transmission of the influenza is from the raw untreated pig waste containing lungs used in the production of mink feed. Because the first clinical symptoms were observed few weeks after the raw pig waste was added to the wet mink feed.

Summary In a previous project, we screened the American mink Bacterial Artificial Chromosome library, CHORI-231, for genes potentially involved in various coat colour phenotypes in the American mink. Subsequently, we 454 sequenced the inserts containing these genes and developed microsatellite markers for each of these genes. Here, we describe a lack of association between three different ‘roan-type' phenotypes represented by Cross, Stardust and Cinnamon in American mink and six different genes that we considered to be potentially linked to these phenotypes. Thus, c-KIT (HUGO-approved symbol KIT), ATOH-1 (HUGO-approved symbol ATOH1) and POMC were excluded as potential candidates for these three phenotypes. In addition, MITF and SLC24A5 were excluded for Cross and Cinnamon, and KITL (HUGO-approved symbol KITLG) for Cross and Stardust. Although most of these genes have been implicated as the cause of similar phenotypes in other mammals, including horses, pigs, cows, dogs, cats, mice and humans, they do not appear to be responsible for comparable phenotypes found in American mink.

Tigger elements belong to the Tc1/Mariner family of DNA transposons which is remarkably widespread in nature with homologs present in organisms as diverse as fungi, plants and animals. In this report, we present the nucleotide sequence of a defragmented Tigger1 element from the genome of the American mink. The element is 2,274 bp long, carries 13 bp terminal inverted repeats (TIRs) and contains the vestiges of two open reading frames (ORFs), one of which is similar to the centromere associated protein CENP B. In addition, we estimate that the genome of the American mink contains approximately 1000 Tigger1 elements, but find no evidence for the transcription of extant elements in the mink.

The introduction of American mink (Neovison vison; hereafter mink) into Europe has had severe impacts on many native wildlife species, including the water vole (Arvicola amphibius) in mainland Britain. Although trapping has been widely used to attempt to control mink, managers have little direct evidence of its effect on mink density or distribution, particularly where immigration of mink from nearby areas is inevitable. Such evidence is needed to justify the use of lethal methods in conservation policy. During 2006–2010 we removed mink from the River Monnow Catchment in western Britain, using track-recording rafts to monitor continuously for mink presence, guiding a strategic trapping effort. The area monitored and trapped was increased in stages, from a core sub-catchment with 109 km of water-course in 2006, to a 421-km2 catchment with 203 km of water-course in 2009. In each successive sub-catchment, mink detection and capture rates declined rapidly to near-zero levels after trapping began. Detections and captures showed seasonal peaks in every year corresponding to known dispersal periods, but also declined steadily from year to year, with increasing periods in which we did not detect mink. These results suggested that each sub-catchment was cleared of mink within a few months, with subsequent captures attributable to immigration. On average, we detected each mink 5.1 times before capture (daily probability of detection = 0.059 per mink and raft), and trapped them 3.4 days after deploying traps in response. On average, mink entering the area were likely to have been present for less than 13 days before capture. Water voles had been extinct in the Monnow Catchment since the 1980s. During 2006–2008 (starting 6 months after mink trapping commenced), we released 700 captive-bred water voles into the treatment area to re-establish a wild population. Persistence of this population through the 4 years of the project was considered indicative of effective mink control. This study demonstrates that, even in a mainland context, a systematic trapping strategy can have a substantial impact on the density and distribution of a damaging species, in this case allowing the restoration of a native prey species. © 2013 The Wildlife Society

Mercury concentrations were examined in livers of free-ranging mink (Neovison vison) trapped in the lower Great Lakes basin from 1998 to 2006. Significant geographic variation in total mercury levels was found in mink from 13 Great Lakes locations, many of which are within Great Lakes Areas of Concern (AOCs). Total mercury levels in mink from these locations were generally low to moderate, with means (±SE) ranging from 0.99 (±0.36) μg/g dry weight in mink from inland Lake Erie to 7.31 (±1.52) μg/g in mink from Walpole Island in the St. Clair River AOC. Overall, mercury exposure was highest in mink trapped in locations associated with large riverine wetlands. Total mercury concentrations were negatively related to the percentage of mercury present as methylmercury and positively related to selenium concentrations, consistent with increasing demethylation of methylmercury with increasing total mercury concentrations. One-year old mink had significantly higher levels of mercury and selenium than mink under 1 year but similar to mink 2 years of age and older. Mercury levels were below those associated with mercury toxicity. Concentrations of cadmium, lead and arsenic were low and largely associated with environmental background levels. Significant age and sex effects were found for cadmium. Lead levels were significantly lower in mink infected by the lung nematode parasite compared to uninfected animals. Further studies of biomagnification of methylmercury in wetland environments, where top predators such as mink may be an increased risk of exposure, are warranted.