Global Ecology and Conservation (Oct 2023)
Eel translocation from a conservation perspective: A coupled systematic and narrative review
Abstract
Translocation is used as a conservation action on a large panel of species, but efficiency of such a measure is still under investigation. This study reviews and synthesizes the existing research evidence to address how translocation of eels could be efficient from a conservation perspective. Anguilla spp. are endangered and translocation has been used to manage their population since the middle of XIXth century. Eels’ translocation can follow different approaches, depending on the objectives and context. Assessing the outcome of translocation projects aiming at restoring eel population is complex, mainly because the last part of its lifecycle, reproduction, is unresolved and has never been observed in the wild. We thus combine a systematic and narrative review approach. We first generated a data set of 956 articles published between 1933 and 2021. Based on a thematic analysis, we linked eel life traits with the main concepts identified in the corresponding corpus. This quantitative approach revealed key controversies about the effect of translocation on eel biological processes. The main thematic associated to translocation were survival, migration and selection by environment. These thematic were further analyses within a narrative review on the basis of a selection of recent articles. The review revealed that there is a consensus on the fact that translocation interacts with natural selection processes (phenotype/environment mismatch), and that translocated eels migrate towards the reproduction area as silver eels, but there are still research gaps on the comparative survival of translocated and wild eels. An emerging thematic was the effect of eel translocation at the community level. Based on review findings, the future research have to focus on the direct comparison of the ecology of translocated eels and their wild counterparts in the natural environment as well as the study of the translocation actions’ impact at community level.
