The Role of Special Fish Habitats in Biodiversity Conservation and Sustainable Fisheries

Occupying a mere fraction of the Earth’s land surface, freshwater ecosystems are disproportionately rich in biodiversity and indispensable for human well-being and sustainable development. Nevertheless, these systems are undergoing accelerated biodiversity loss, driven by intensifying anthropogenic pressures that often surpass the impacts observed in terrestrial and marine environments. Protected areas are central to biodiversity conservation, but their effectiveness in freshwater systems is limited by hydrological connectivity and the mismatch between fixed boundaries and dynamic ecological processes. In this study, we assessed the ecological and fisheries performance of Special Fish Habitats (SFHs) in Serbia by comparing 25 SFH and 19 non-SFH localities across the Ibar and Nišava River basins, using field surveys conducted through standardized electrofishing from 2022 to 2025 and fish stock monitoring records covering 2016–2021. Fish production, biodiversity, ecological status, and population sustainability were evaluated through the ES-HIPPOfishing model, complemented by multivariate statistical and machine learning analyses. SFHs showed generally higher productivity and better water quality, but none of the direct comparisons were statistically significant. To our knowledge, this is the first study to systematically evaluate SFHs in Serbia, providing a robust scientific basis for refining freshwater protected area networks and offering actionable insights for biodiversity conservation in pressured river systems.