REVIVE: A feasibility assessment tool for freshwater fish conservation translocations in Mediterranean rivers

Conservation translocation is a management action applied for population recovery of threatened freshwater fishes, often however with partially successful outcome, mainly due to inadequate feasibility assessment prior to the translo-cation. Up to date, feasibility assessments have been mainly focused on economically important species (e.g., salmonids) inhabiting perennial rivers, while little attention has been given to fish translocations in rivers in Mediterranean climate areas. In this study, we developed a robust feasibility assessment tool for freshwater fish trans -locations in Mediterranean-type riverine ecosystems within an interdisciplinary, multispecies approach. The REVIVE tool integrates quantitative and semi-quantitative data, incorporates uncertainty and consists of two main components. The first component is the evaluation of the potential release water bodies (R-WBs) for their suitability for the planned translocation, incorporating a number of essential criteria for Mediterranean rivers, with emphasis on flow regime and habitat quantity. Additional criteria include the current and historical presence of the target species, water and biolog-ical quality, habitat suitability in terms of the ecological requirements of the target species, alien invasive species' pres-sure, and hydromorphological pressures, including their mitigation potential. The second component is the evaluation of the potential source water bodies (S-WBs) in terms of genetic compatibility and provision of a sufficient number of propagules. A trial application in a Mediterranean basin (Vassilopotamos River, Southern Greece) for the potential translocation of two threatened cyprinids in five R-WBs indicated the robustness of the tool. This integrative, flexible tool combines several elements identified as essential in reintroduction biology and can have wider applications, for a multitude of freshwater fish taxa and riverine systems, maximizing the success of planned translocation actions by nat-ural resources' managers. Modifications to enable its transferability to other river types or fish taxa are also discussed.

Automated summary

This study developed a reliable tool for assessing the feasibility of freshwater fish translocations in Mediterranean-type riverine ecosystems. The tool integrates quantitative and semi-quantitative data, incorporates uncertainty, and consists of two main components: evaluating the suitability of potential release water bodies and evaluating the genetic compatibility and propagule provision of potential source water bodies. A trial application in a Mediterranean basin demonstrated the robustness of the tool.