Hard times for catadromous fish: the case of the European eel (Anguilla anguilla, L. 1758)

Catadromous fish species can be defined important organisms for their ecological, economical, and cultural value. Because of a complex life cycle, catadromous fish species are exhibited to the cumulative effect of multiple anthropogenic threats that resulted in worldwide decline since the beginning of the 20th century. Among the most iconic catadromous species, the European eel Anguilla anguilla has aroused considerable interest, and to date, many aspects of its life cycle remain relatively unknown. Although conspicuous efforts by the research to ensure the perpetuation of the species were conducted, the identification of the best tools to reduce the threats that affect eels remains challenging. In this narrative review, the state of the knowledge and main threats about the life cycle, the habitat occupancy, the recruitment, and migration patterns of the European eel have been reported.