Unauthorized Translocations of Threatened Fauna in Freshwater Ecosystems: Insights From the Iberian Southeast

Unauthorized translocations of native and threatened wildlife are widely conducted for conservation purposes. This illegal practice remains understudied and is poorly considered by wildlife managers despite its important socioecological implications. By focusing on the southeastern Iberian Peninsula as a case study, we combined data from freshwater biodiversity monitoring programs, published records and local expert knowledge to provide a comprehensive assessment of the magnitude of unauthorized translocations in freshwater ecosystems. A total of 14 cases of covertly translocated populations were recorded, involving 10 freshwater vertebrate species (six fish and four amphibians). All these species are classified as threatened taxa (i.e., critically endangered, endangered or vulnerable) at a global, national or regional level, seven of them being Iberian endemisms. At least nine out of these unauthorized translocations have resulted in self-sustaining populations, but their impact on local biodiversity and recipient ecosystems' functioning remains to be assessed. This case study suggests that unauthorized translocations could be an emerging conservation issue in freshwater ecosystems, highlighting the need for implementing integrative management approaches to halt this illegal practice at source. These management approaches should include a more proactive attitude by environmental authorities towards official conservation translocation programs and increased social awareness of the potential impacts of unauthorized translocations.