The IUCN Red List lists the European eel (Angiulla angiulla) as critically endangered, with speculation highlighting the role of habitat restrictions from dam building in the collapse of the species. By combining GBIF-mediated data with 16th- and 19th-century records on freshwater fish in Spain, the authors created current and historical distribution models for the Iberian Peninsula. After locating all Spanish and Portuguese dams in the distribution models, the authors calculated potential of each dam to contribute to recovery of eel habitats and identified the most important dams. They concluded that making just 12 dams permeable to eels could restore access to 40 per cent of the animals’ historic range, while making modifications to 76 dams could achieve an 80 per cent recovery.
Clavero, M., & Hermoso, V. (2015). Historical data to plan the recovery of the European eel. Journal of Applied Ecology, 52(4), 960–968. doi:10.1111/1365-2664.12446