High mitochondrial DNA diversity of an introduced alien carnivore: comparison of feral and ranch American mink Neovison vison in Poland

Uncovering the Male Presence in Parthenogenetic Marchalina hellenica (Hemiptera: Marchalinidae): Insights into Its mtDNA Divergence and Reproduction Strategy

Marchalina hellenica (Hemiptera: Marchalinidae), an endemic species in Greece and Turkey, is a major contributor to the annual honey production in its native range. However, in the areas that it invades, lacking natural enemies, it has detrimental effects on pine trees and potentially contributes to tree mortality. Although it was originally reported as thelytokous, males were later reported in Turkey and on several of the islands of Greece. To further disambiguate the exact parthenogenetic reproduction strategy of M. hellenica, we studied the emergence pattern of male individuals in Greece for two consecutive years (2021 and 2022). Furthermore, we examined the genetic variation among 15 geographically distant populations of M. hellenica in Greece using a mitochondrial DNA marker and compared the results with data from Turkey. The findings of this study document the existence of an additional M. hellenica population in its native range that repeatedly produces males, apart from the areas of Greece and Turkey in which they were initially reported, suggesting that males play a major, so far unknown role in the reproduction of this species. The populations in Greece and Turkey exhibited a strong genetic affinity, while human-aided dispersal seems to have obscured the genetic pattern acquired.

Invasive and Alien Mammal Species in Poland—A Review

About 20 species of non-native mammals have been recorded in Poland. Some of them are already extinct or have been extirpated, while others are widely distributed and may affect the native biota in Poland. We review the literature on 15 non-native species found in this country, discussing their origin, distribution, and presence on lists of invasive species that pose a threat to wildlife in Poland and the EU. In addition, we discuss current knowledge on their impact on Polish ecosystems. However, on many of these species, there is little information, and the consequences of their presence remain unclear. Therefore, we emphasize the importance of this review for appropriate species management and suggest the introduction of monitoring, especially of species whose populations are increasing.

Introduced, Mixed, and Peripheral: Conservation of Mitochondrial-DNA Lineages in the Wild Boar (Sus scrofa L.) Population in the Urals

Translocations and introductions are important events that allow organisms to overcome natural barriers. The genetic background of colonization success and genetic consequences of the establishment of populations in new environments are of great interest for predicting species’ colonization success. The wild boar has been introduced into many parts of the world. We analyzed sequences of the mitochondrial-DNA control region in the wild boars introduced into the Ural region and compared them with sequences from founder populations (from Europe, the Caucasus, Central Asia, and the Far East). We found that the introduced population has high genetic diversity. Haplotypes from all the major phylogenetic clades were detected in the analyzed group of the animals from the Urals. In this group, no haplotypes identical to Far Eastern sequences were detectable despite a large number of founders from that region. The contribution of lineages originating from Eastern Europe was greater than expected from the proportions (%) of European and Asian animals in the founder populations. This is the first study on the genetic diversity and structure of a wild boar population of mixed origin at the northern periphery of this species’ geographical range.

Effects of Dietary Protein and Energy Levels on Growth Performance, Nutrient Digestibility, and Serum Biochemical Parameters of Growing Male Mink (Neovison vison)

The objective of this experiment was to determine the optimum dietary metabolic energy (ME) and crude protein (CP) levels of growing male mink. One hundred forty-four healthy male minks at 75 days were randomly allocated into the six groups with 24 replicates, which was one mink for each replicate. The mink were fed six experimental diets with two CP levels (31.59 and 35.63%) and three ME levels (14.17, 15.96, and 17.73 MJ/kg) for a 7-day preliminary period and then for an 88-day experimental period. The final body weight (BW), average daily gain (ADG), feed conversion ratio (FCR), fat digestibility, energy intake, the concentration of glucose (GLU), and low-density lipoprotein (LDL) of the mink were significantly increased by the CP or ME levels (P < 0.05). In addition, CP levels significantly (P < 0.01) increased the N intake and N retention. Dietary ME levels increased the utilization of gross energy. Obviously, there were significant CP × ME interactions for the final BW, ADG, fat digestibility, energy utilization, GLU, LDL (P < 0.01), and triglyceride contents (P < 0.05). Therefore, the optimum CP and ME levels were 35.97% and 18.18 MJ/kg, which can improve growth, enhance nutrient digestion, and promote blood lipid metabolism in growing mink.

Diversity and transmission of Aleutian mink disease virus in feral and farmed American mink and native mustelids

Aleutian mink disease virus (AMDV), which causes Aleutian disease, is widely spread both in farmed mink and wild mustelids. However, only limited data are available on the role of wild animals in AMDV transmission and spread. Our aim was to shed light on AMDV transmission among wild mustelids and estimate the effect of intense farming practices on the virus circulation by studying AMDV prevalence and genetic diversity among wild mustelids in Poland. We compared AMDV seroprevalence and proportion of PCR-positive individuals in American mink, polecats, otters, stone martens, and pine martens and used the phylogenetic analysis of the NS1 region to study transmission. In addition, we used a metagenomic approach to sequence complete AMDV genomes from tissue samples. In eastern Poland, AMDV seroprevalence in wild mustelids varied from 22 per cent in otters to 62 per cent and 64 per cent in stone martens and feral mink, respectively. All studied antibody-positive mink were also PCR positive, whereas only 10, 15, and 18 per cent of antibody-positive polecats, pine martens, and stone martens, respectively, were PCR positive, suggesting lower virus persistence among these animal species as compared to feral mink. In phylogenetic analysis, most sequences from feral mink formed region-specific clusters that have most likely emerged through multiple introductions of AMDV to feral mink population over decades. However, virus spread between regions was also observed. Virus sequences derived from farmed and wild animals formed separate subclusters in the phylogenetic tree, and no signs of recent virus transmission between farmed and wild animals were observed despite the frequent inflow of farmed mink escapees to wild populations. These results provide new information about the role of different mustelid species in AMDV transmission and about virus circulation among the wild mustelids. In addition, we pinpoint gaps of knowledge, where more studies are needed to achieve a comprehensive picture of AMDV transmission.

Aleutian mink disease: Spatio-temporal variation of prevalence and influence on the feral American mink

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

High Genetic Diversity of an Invasive Alien Species: Comparison between Fur-Farmed and Feral American Mink (Neovison vison) in China

Simple Summary

The American mink (Neovison vison) is one of the best-known and most widespread invasive species in China and worldwide. To investigate the genetic characteristics and increase comprehension of the invasiveness process for this species, we compared the genetic characteristics of farmed and feral populations in northeastern China using mitochondrial DNA sequences and microsatellite loci. We found a relatively high diversity among the feral populations that was as high as that of the farmed mink. This demonstrated that high genetic diversity promotes the invasiveness and rapid evolution in the wild.

Abstract

Genetic characteristics play an important role in alien species for achieving high adaptation and rapid evolution in a new environment. The American mink (Neovison vison) is one of the best-known and most widespread invasive species that has successfully invaded the Eurasian mainland over quite a short period, including most parts of northeastern China. However, genetic information on farmed and feral American mink populations introduced in China is completely lacking. In this study, we combined mitochondrial DNA sequences and polymorphic microsatellites to examine the genetic divergence and genetic diversity of farmed and feral American mink populations. Our results suggest that there is admixture of individuals of different genetic characteristics between farmed and feral populations of mink. Furthermore, the genetic diversity of both farmed and feral American mink populations was high, and no bottleneck or population expansion was detected in most of the populations. These findings not only highlight the genetic characteristics of American mink in northeastern China but also contribute to the general understanding of the invasiveness of farmed species.

How Selective Breeding Has Changed the Morphology of the American Mink (Neovison vison)-A Comparative Analysis of Farm and Feral Animals

In this study, we performed a comparative analysis of the morphological traits between feral (n = 43) and farm (n = 200) individuals of the American mink in Poland to address the question of how multigenerational intensive selective breeding has morphologically differentiated these two populations. Nine body measurements and two proportion coefficients were obtained using adult individuals. The significance of differences between population means was assessed using the Wilcoxon test for independent samples, while the Kruskal-Wallis test was used to compare sex-population groups. Spearman's correlation coefficients between measurements were estimated for each population. We also performed Principal Component Analysis (PCA) to identify the variables that were most closely correlated with variation in the trait measurements and to investigate the morphological differences between farm and feral minks. We found that the farm minks exhibited significantly higher mean values for eight out of eleven studied traits. Moreover, significant changes in forelimb length, with no concomitant changes in hindlimb length, were accompanied by differences in body shape: trapezoidal in feral minks and rectangular in farm minks. The PCA suggested an almost complete separation of the two populations and indicated that sexes were quite separate; farm males in particular constitute a wholly discrete cluster. Such a clear differentiation between the two populations and sexes over a period of several decades highlights the intensity of selective breeding in shaping the morphology of these animals.

Digestive tract nematode infections in non-native invasive American mink with the first molecular identification of Molineus patens

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

Comparing raccoon major histocompatibility complex diversity in native and introduced ranges: Evidence for the importance of functional immune diversity for adaptation and survival in novel environments

The adaptive potential of invasive species is related to the genetic diversity of the invader, which is influenced by genetic drift and natural selection. Typically, the genetic diversity of invaders is studied with neutral genetic markers; however, the expectation of reduced diversity has not been consistently supported by empirical studies. Here, we describe and interpret genetic diversity at both neutral microsatellite loci and the immune-related MHC-DRB locus of native and invasive populations of raccoon to better understand of how drift and selection impact patterns of genetic diversity during the invasion process. We found that despite the loss of many MHC (major histocompatibility complex) alleles in comparison with native populations, functional MHC supertypes are preserved in the invasive region. In the native raccoon population, the number of supertypes within individuals was higher than expected under a neutral model. The high level of individual functional divergence may facilitate the adaptation to local conditions in the invasive range. In the invasive populations, we also detected increased population structure at microsatellites compared to the MHC locus, further suggesting that balancing selection is acting on adaptively important regions of the raccoon genome. Finally, we found that alleles known to exhibit resistance to rabies in the native range, Prlo-DRB*4, Prlo-DRB*16 and Prlo-DRB*102, were the most common alleles in the European populations, suggesting directional selection is acting on this locus. Our research shows empirical support for the importance of functional immune diversity for adaptation and survival in novel environments.

Opportunities for genomic selection in American mink: A simulation study

Genomic selection can be considered as an effective tool for developing breeding programs in American mink. However, the genetic gains for economically important traits can be influenced by the accuracy of genomic predictions. The objective of this study was to investigate the prediction accuracies of traditional best linear unbiased prediction (BLUP), multi-step genomic BLUP (GBLUP) and single-step GBLUP (ssGBLUP) methods in American mink using simulated data with different levels of heritability, marker density, training set (TS) sizes and selection designs based on either phenotypic performance or estimated breeding values (EBVs). Under EBV selection design, the accuracy of BLUP predictions was increased by 38% and 44% for h2 = 0.10, 27% and 29% for h2 = 0.20, and 5.8% and 6% for h2 = 0.50 using GBLUP and ssGBLUP methods, respectively. Under phenotypic selection design, the accuracies of prediction by ssGBLUP method were 11.8% and 15.4% higher than those obtained by GBLUP for heritability of 0.10 and 0.20, respectively. However, the efficiency of ssGBLUP and GBLUP was not influenced by selection design at higher level of heritability (h2 = 0.50). Furthermore, higher selection intensity increased the bias of predictions in both pedigree-based and genomic evaluations. Regardless of selection design, TS sizes for GBLUP and ssGBLUP methods should be at least 3000 to achieve more accuracy than using BLUP for heritability of 0.50 and marker density of 10k and 50k. Overall, more accurate predictions were obtained using ssGBLUP method particularly for lowly heritable traits and low density of markers. Our results indicated that TS sizes should be optimized in accordance with heritability level, marker density, selection design and prediction method for genomic selection in American mink. The results provided an initial framework for designing genomic selection in mink breeding programs.

Propagule pressure and hunting pressure jointly determine genetic evolution in insular populations of a global frog invader

Islands are often considered to be more susceptible to biological invasions and to suffer greater impacts from invaders than mainland areas, and this difference is generally attributed to differences in species introductions, ecological factors or human activities between islands and mainland areas. Genetic variation, as a good estimate of evolutionary potential, can influence the invasion process and impacts of alien species. However, few studies have compared the genetic diversity of alien species between islands and a corresponding mainland. Here, we examined the genetic variation and differentiation in feral populations (30 sampled individuals/population) of a globally invasive species (the American bullfrog, Lithobates catesbeianus) that was extensively farmed on 14 islands in the Zhoushan Archipelago of China and in three nearby regions on the mainland. We quantified the relative importance of propagule pressure and hunting pressures on the genetic variation of bullfrog populations and found that insular populations have greater genetic variation than their mainland counterparts. Although genetic differentiation between the populations was observed, no evidence of recent bottlenecks or population expansion in any of the tested population was found. Our results suggest that the propagule pressures of bullfrogs escaping from farms, multiple releases and hunting pressure influence the genetic variation among bullfrog populations. These results might have important implications for understanding the establishment and evolution of alien species on islands and for the management of invasive species.

Genetic structure of introduced American mink (Neovison vison) in Patagonia: colonisation insights and implications for control and management strategies

Context Biological invasions have caused dramatic changes in native biodiversity and ecosystem function. Studies of genetic variation and evolutionary changes are useful for understanding population dynamics during biological invasions, and shed light on management, prevention and restoration strategies. Aims This study aimed to investigate the structure and genetic variability of American mink (Neovison vison), an invasive species in southern South America, introduced for fur farming in the 1930s. Methods Samples from 153 mink were obtained from 12 locations in southern Chile to sequence the mitochondrial DNA (mtDNA) control region and to genotype 11 polymorphic microsatellite loci. Key results The highest mtDNA diversity was detected in Puerto Cisnes, suggesting multiple introductions and/or the most probable area where mink was first introduced. The latter is also supported by microsatellite data, because a high percentage of individuals from different locations were assigned to this location. All other locations showed low or no mtDNA diversity, possibly due to founder effect. The results also indicate marked population structure, with three genetic clusters coincident with the main historical introduction points, with low dispersal among them. Conclusions The results suggest that control strategies for American mink in southern Chile should be concentrated on these three genetically differentiated management units, and particularly on source populations and locations with low effective population size and restricted connectivity. Implications Genetic approaches have been used for the management of numerous alien species worldwide. Recommendations delivered here for American mink control could also be implemented in other regions and for other invasive species with similar genetic diversity distribution and connectivity.

Hybridization of domestic mink with wild American mink (Neovison vison) in eastern Canada

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.

Reduced Genetic Diversity and Increased Structure in American Mink on the Swedish Coast following Invasive Species Control

Eradication and population reductions are often used to mitigate the negative impacts of non-native invasive species on native biodiversity. However, monitoring the effectiveness of non-native species control programmes is necessary to evaluate the efficacy of these measures. Genetic monitoring could provide valuable insights into temporal changes in demographic, ecological, and evolutionary processes in invasive populations being subject to control programmes. Such programmes should cause a decrease in effective population size and/or in genetic diversity of the targeted non-native species and an increase in population genetic structuring over time. We used microsatellite DNA data from American mink (Neovison vison) to determine whether the removal of this predator on the Koster Islands archipelago and the nearby Swedish mainland affected genetic variation over six consecutive years of mink culling by trappers as part of a population control programme. We found that on Koster Islands allelic richness decreased (from on average 4.53 to 3.55), genetic structuring increased, and effective population size did not change. In contrast, the mink population from the Swedish coast showed no changes in genetic diversity or structure, suggesting the stability of this population over 6 years of culling. Effective population size did not change over time but was higher on the coast than on the islands across all years. Migration rates from the islands to the coast were almost two times higher than from the coast to the islands. Most migrants leaving the coast were localised on the southern edge of the archipelago, as expected from the direction of the sea current between the two sites. Genetic monitoring provided valuable information on temporal changes in the population of American mink suggesting that this approach can be used to evaluate and improve control programmes of invasive vertebrates.

Population genetic structure in farm and feral American mink (Neovison vison) inferred from RAD sequencing-generated single nucleotide polymorphisms

Feral American mink populations (), derived from mink farms, are widespread in Europe. In this study we investigated genetic diversity and genetic differentiation between feral and farm mink using a panel of genetic markers (194 SNP) generated from RAD sequencing data. Sampling included a total of 211 individuals from 14 populations, 4 feral and 10 from farms, the latter including a total of 7 color types (Brown, Black, Mahogany, Sapphire, White, Pearl, and Silver). Our study revealed similar low levels of genetic diversity in both farm and feral mink. Results are consistent with small effective population size as a consequence of line selection in the farms and founder effects of a few escapees from the farms in feral populations. Moderately high genetic differentiation was found between farm and feral animals, suggesting a scenario in which wild populations were founded from farm escapes a few decades ago. Currently, escapes and gene flow are probably limited. Genetic differentiation was higher among farm color types than among farms, consistent with line selection using few individuals to create the lines. Finally, no indications of inbreeding were found in either farm or feral samples, with significant negative values found in most farm samples, showing farms are successful in avoiding inbreeding.

Genetic evidence for multiple sources of the non-native fish Cichlasoma urophthalmus (Günther; Mayan Cichlids) in southern Florida

The number and diversity of source populations may influence the genetic diversity of newly introduced populations and affect the likelihood of their establishment and spread. We used the cytochrome b mitochondrial gene and nuclear microsatellite loci to identify the sources of a successful invader in southern Florida, USA, Cichlasoma urophthalmus (Mayan cichlid). Our cytochrome b data supported an introduction from Guatemala, while our microsatellite data suggested movement of Mayan Cichlids from the upper Yucatán Peninsula to Guatemala and introductions from Guatemala and Belize to Florida. The mismatch between mitochondrial and nuclear genomes suggests admixture of a female lineage from Guatemala, where all individuals were fixed for the mitochondrial haplotype found in the introduced population, and a more diverse but also relatively small number of individuals from Belize. The Florida cytochrome b haplotype appears to be absent from Belize (0 out of 136 fish screened from Belize had this haplotype). Genetic structure within the Florida population was minimal, indicating a panmictic population, while Mexican and Central American samples displayed more genetic subdivision. Individuals from the Upper Yucatán Peninsula and the Petén region of Guatemala were more genetically similar to each other than to fish from nearby sites and movement of Mayan Cichlids between these regions occurred thousands of generations ago, suggestive of pre-Columbian human transportation of Mayan Cichlids through this region. Mayan Cichlids present a rare example of cytonuclear disequilibrium and reduced genetic diversity in the introduced population that persists more than 30 years (at least 7-8 generations) after introduction. We suggest that hybridization occurred in ornamental fish farms in Florida and may contribute their establishment in the novel habitat. Hybridization prior to release may contribute to other successful invasions.

The use of chemical markers for the identification of farm escapees in feral mink populations

Variations in the contaminant burden in feral and ranch mink, resulting from differences in their diet, may permit the identification of farm escapees. However, this is only possible in the case of contaminants that accumulate to significantly different levels in the two groups of animals. The main objective of this study was to identify chemical markers whose concentrations differ between feral and ranch mink, by analyzing the accumulation of 13 chemical elements in liver and kidney samples. Total mercury levels were up to 15-fold higher in kidney, and up to 7-fold higher in liver of feral mink compared with ranch mink. The majority of feral mink samples analyzed for mercury, contained concentrations that ranged from 1 to 5 μg/g in kidney (68 %) and from 1 to 5 μg/g in liver (70 %). In comparison, the organs of ranch mink had significantly lower levels of mercury: 95 % of kidney samples had concentrations below 1 μg/g and 82 % of liver samples had concentrations below 1 μg/g. Small geographical variations in Hg levels were observed in mink from the four studied feral populations. Significant differences in Cu concentrations between ranch and feral mink were also detected, with low variation within the two groups. Less pronounced differences were recorded for other chemical elements. These data suggest that Hg and Cu may be used as chemical markers for the identification of first generation mink farm escapees.

Assessing the cryptic invasion of a domestic conspecific: American mink in their native range

Control of invasions is facilitated by their early detection, but this may be difficult when invasions are cryptic due to similarity between invaders and native species. Domesticated conspecifics offer an interesting example of cryptic invasions because they have the ability to hybridize with their native counterparts, and can thus facilitate the introgression of maladaptive genes. We assessed the cryptic invasion of escaped domestic American mink (Neovison vison) within their native range. Feral mink are a known alien invader in many parts of the world, but invasion of their native range is not well understood. We genetically profiled 233 captive domestic mink from different farms in Ontario, Canada and 299 free-ranging mink from Ontario, and used assignments tests to ascertain genetic ancestries of free-ranging animals. We found that 18% of free-ranging mink were either escaped domestic animals or hybrids, and a tree regression showed that these domestic genotypes were most likely to occur south of a latitude of 43.13°N, within the distribution of mink farms in Ontario. Thus, domestic mink appear not to have established populations in Ontario in locations without fur farms. We suspect that maladaptation of domestic mink and outbreeding depression of hybrid and introgressed mink have limited their spread. Mink farm density and proximity to mink farms were not important predictors of domestic genotypes but rather, certain mink farms appeared to be important sources of escaped domestic animals. Our results show that not all mink farms are equal with respect to biosecurity, and thus that the spread of domestic genotypes can be mitigated by improved biosecurity.

Population viability analysis of American mink (Neovison vison) escaped from Danish mink farms

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.