Expert risk assessment and recovery actions for rare and threatened freshwater fishes in the Wet Tropics of Australia

Context Freshwater ecosystems are experiencing globally unprecedented biodiversity declines. Australia’s Wet Tropics is a biodiversity hotspot containing a diverse assemblage of endemic freshwater fishes, many of which are at risk of extinction. Aims Our study aimed to understand the risk of impacts of historical, emerging, and intensifying threats to these species, and address critical knowledge gaps that has hindered conservation planning. Methods An expert workshop assessed 22 endemic, rare, and/or threatened freshwater fish species, integrating all available empirical research with regional expert knowledge of species ecology, distribution, and threat exposure. Key results The assessment identified invasive species, climate-driven changes to temperature and hydrology, habitat and water quality degradation, and hybridization with translocated native fishes as among the most severe threats, particularly for narrowly distributed rainbowfishes and amphidromous cling gobies. Several species were rated as high or very high risk of extinction due to these threats, highlighting the urgent need to develop a formal recovery strategy. Conclusions The suite of candidate actions proposed by experts offered a clear and actionable foundation from which an effective plan can be built. Actions included habitat protection and restoration, invasive species control, improved riparian management, targeted translocations and captive breeding, and priority research to resolve taxonomic uncertainty and fill critical data gaps. Implications Collectively, this work provides a basis for developing species’ conservation listings and multi-species recovery strategies, while highlighting the urgent need for coordinated, evidence-informed conservation interventions to avert biodiversity loss in a region of high freshwater fish diversity.