Expected Mitochondrial Haplotype Richness in Remaining Populations of the Critically Endangered European Mink Mustela lutreola and Its Conservation Implications

The European mink <i>Mustela lutreola</i> is one of the most threatened carnivores in Europe, having suffered dramatic range contractions and severe population fragmentation. Accurate knowledge of its genetic diversity is crucial for conservation planning, yet earlier studies based on partial mitochondrial markers offered limited resolution and often underestimated haplotype richness. In this study, complete mitochondrial genomes from four extant populations (Russia, <i>n</i> = 11; Romania, <i>n</i> = 16; Germany, <i>n</i> = 24; France-Spain, <i>n</i> = 15) were analysed using a suite of non-parametric and asymptotic estimators (Fisher's <i>α</i>, <i>ACE</i>, <i>Jackknife1</i>, <i>Bootstrap</i>, <i>Chao1</i>-based iNEXT) together with negative binomial modelling. A total of 41 haplotypes were detected, but extrapolated estimates indicated substantially higher richness, particularly in populations dominated by singletons. Rarefaction and extrapolation analyses revealed that sample sizes of 70-130 individuals per population are needed to approach complete haplotype detection. The France-Spain and Romania populations harboured the highest predicted richness, whereas Germany and Russia, both represented by ex situ stocks, showed lower diversity. These results refine earlier assumptions of extreme homogeneity in the Western population and demonstrate that significant mitochondrial variation persists at the continental scale. The study provides quantitative benchmarks for sampling design and genetic management, supporting preservation of evolutionary potential in this critically endangered species.