Coordination is not admixture: gene flow in the European mink requires staged genomic and risk-based justification

Abstract

This Letter comments on Nummert-Meister et al. (2026) and their recommendation for closer management of eastern and western captive populations of the critically endangered European mink Mustela lutreola . It agrees that demographic urgency, fragmentation and continuing genetic erosion require coordinated conservation action, and that management cannot always wait for perfect evidence. However, it argues that coordination, genetic rescue and admixture are not equivalent decisions. The relevant question is not whether conservation programmes should communicate, coordinate or act, but under what conditions gene flow between differentiated captive lineages would provide a net conservation benefit at acceptable risk. Microsatellite, short mitochondrial DNA and studbook evidence are valuable for operational management, yet they do not by themselves resolve the long-term risks of between-lineage admixture, especially where release context, disease exposure, demographic status and lineage histories may affect outcomes. The Letter therefore supports urgent, staged and evidence-responsive action, while cautioning that uncertainty should be made explicit rather than converted into permission for routine admixture.