Age Structure Differences in American Mink , Mustela vison , Populations under Varying Harvest Regimes
Two American Mink populations were examined using canine tooth cementum annuli to assess age structure of harvested segments of the populations. Trapping mortality was different between these two populations. Comparisons are made with a Montana Mink population. I propose that forbearer managers can readily assess relative harvest pressures by analyzing the age structure of a Mink population, and offer management recommendations for populations displaying various age structures.
Estimation of the Age and Reproductive Performance of Wild-Born and Escaped Mink (Neovison vison) Caught in the Wild in Denmark
Simple Summary Previous studies of wild caught mink in Denmark showed that 30–80% had recently escaped from farms. Therefore, it is debated whether a self-sustaining feral mink population is established in Denmark or whether the population rests upon a continuous contribution of captive-born farm mink. Knowledge regarding the reproduction and mortality of mink adapted for living in the wild is important for the management of feral mink. In this study, we separated wild-born from captive-born mink caught in the wild in Denmark. To be able to age the mink in this study, an age determination model for mink was developed based on the width of the pulp cavity. The mean litter size of wild-born female mink was 7.6 (range: 5–11 kits). The annual turnover of mink caught in the wild was estimated to be 66%, and the yearly mortality was 69%; thus, the population of wild-born mink is slightly declining. The results confirmed that the wild-born mink population in Denmark is reproducing and self-sustaining without a continuous influx of captive-born mink escaped from farms. The effect of escaped mink on the wild mink population will depend on the currently unknown ability of captive mink to survive in the wild. Abstract The feral mink population in Denmark consists of two groups of animals: mink born in the wild and mink that have recently escaped from farms. The aims of this study were to: (1) estimate the reproductive performance and mortality of the Danish mink born in the wild (wild-born) and mink escaped from farms (captive-born); (2) discuss the likelihood of a self-sustaining population of wild-born mink in Denmark; and (3) model the relationship between the pulp cavity width and the age of mink. During 2018, 247 wild caught mink were sent for necropsy at the Danish National Veterinary Institute. Based on body length, 112 were determined as captive-born and 96 as wild-born. The mean litter size ± SE of wild-born females was 7.6 ± 0.9 (range: 5–11 kits) and for captive-born females 5.9 ± 0.9 (range: 1–10 kits). The relationship between age (in months) of mink and pulp cavity width was highly significant. Individuals with a pulp cavity width of >35% were younger than one year. Based on fecundity, the turnover of the mink population was estimated to be 66%, and the yearly mortality was estimated at 69%. Hence, the population is slightly declining. In conclusion, a feral reproducing mink population in Denmark persists without a continuous influx of captive-born mink from farms.
Live Trapping Mink in British Columbia
There have been few live-trapping studies of mink ( Mustela vision ), as McCabe (Jour. Mamm., 30 : 415—423, 1949) has pointed out. This is difficult to explain in view of its wide range, its value as fur, and the ease with which it may be trapped.

Live trapping and tagging mink was a low priority study in Wells Gray Park, British Columbia, from 1951 to 1954. This work was undertaken in slack periods between studies given higher priority. It was designed primarily to test trapping and tagging techniques preliminary to a more detailed study planned for the future. Some data on the extent of movements accumulated and is included here.

McCabe ( loc. cit. ) has reported on a similar study in Wisconsin. Using wooden box-traps, putrid bait, and a variety of means of recognizing individuals, he laid a solid foundation for further live trapping studies. The present study had comparable success with different traps and bait. An additional difference existed in the present study, for the park and its vicinity are contained in a number of registered trap lines. Since the population studied would be subject to commercial trapping, a marking method easily recognized by local trappers was essential. Such marking would enable trappers to report upon tagged animals taken and would also give data on the effect of commercial trapping upon the population.

Limited live trapping took place on most major waters in the southern half of the park, all of which is a wild area and some of which is undisturbed wilderness. Intensive trapping effort was confined to a 1.2 mile stretch of Hemp Creek where it meanders through hay fields and pastures in the vicinity of several small farms adjacent to the park. The elevation here is about 2100 feet. A brief description of the topography and vegetation of …