Testing a recently proposed framework for assessing the success of conservation translocations: the European mudminnow (Umbra krameri) programme in Hungary

Advancing conservation translocation science requires the synthesis and comparative analysis of individual case studies to generate broader evidence-based insights. However, no widely adopted framework currently standardises outcome assessment across diverse translocation programmes. Birot et al. (2025) recently proposed a candidate framework that could potentially provide such a standard. Here, we tested its applicability using the European mudminnow ( Umbra krameri ) translocation programme in Hungary. We assessed the long-term demographic success of two translocations into artificial ponds using the multi-criteria framework proposed by Birot et al. (2025). Population dynamics were monitored for 7–10 years following release, including repeated surveys of abundance, size-class structure, and recruitment. Both populations persisted beyond the species’ maximum lifespan and reproduced repeatedly, as evidenced by repeated occurrences of larvae and juveniles. Detecting multiple size classes indicated recruitment across several generations. Estimated 2022 abundance relative to cumulative release numbers differed between the two populations. Despite interannual fluctuations in captures and temporary removals associated with management interventions, both populations persisted and reproduced over multiple generations. Population dynamics were classified as Establishing/Growing in Illés Pond IV + Pócos Pond B and Growing in Illés Pond VI. Overall progress scores were 0.56 and 0.70, respectively, with Establishing and Growing representing the dominant category contributions. Our results demonstrate that small, isolated, groundwater-fed artificial ponds can support persistent, self-recruiting European mudminnow populations over multiple generations despite the species’ relatively low fecundity. We have established suitable habitats to provide safety and refuge for this endangered species. The framework proposed by Birot et al. (2025) was suitable for evaluating our programme. However, smaller programmes with more limited resources may find such a comprehensive assessment more challenging to implement. Further testing across a wider range of programmes and ecological contexts would help assess its broader applicability.