Description
The Evrotas River Basin in southern Greece represents one of the most important freshwater biodiversity hotspots in the eastern Mediterranean. It is home to two endemic and highly threatened freshwater fish species — the Evrotas minnow (Pelasgus laconicus), listed as Critically Endangered, and the Evrotas chub (Squalius keadicus), listed as Endangered. Both species are restricted to this basin and have suffered severe population declines due to habitat degradation, fragmentation, pollution, and water scarcity driven by over-abstraction for irrigation and climate change.
Led by OIKOM Environmental Studies Ltd. in collaboration with the Hellenic Centre for Marine Research (HCMR), the CASTOR project aims to improve the conservation status of these species and restore ecological integrity in the Evrotas River Basin. Building upon over two decades of scientific research and previous European projects (including LIFE, FP7 and GLOBAQUA), the project introduces innovative, nature-based restoration measures and direct conservation interventions.
Key actions include habitat restoration using beaver dam analogues and nature-based fish passages to reconnect fragmented habitats and increase summer refugia during droughts; species translocations and reinforcement of wild populations through both in situ and ex situ breeding; and monitoring of invasive species, particularly the non-native rainbow trout (Oncorhynchus mykiss).
The project will also establish a Stakeholder Engagement Plan to involve farmers, local communities, and authorities in sustainable water use, while education programmes in local schools will raise awareness of freshwater conservation. Advanced monitoring using environmental DNA (eDNA) will track population recovery and habitat improvements.
Through this integrated approach, CASTOR will set a benchmark for Mediterranean freshwater conservation, combining science-based management, community engagement, and innovative restoration tools to secure the survival of endemic species and the long-term resilience of freshwater ecosystems.
