Anguillids: widely studied yet poorly understood—a literature review of the current state of Anguilla eel research

Abstract

Freshwater eels (Anguillidae) are facing numerous anthropogenic impacts that have led to declines in abundance for nearly all species. They have a complex life history that includes obligate migration and flexible habitat use, characteristics which have generated much research interest in the family. Eels also have high cultural and economic value, further incentivizing the study of key species. We reviewed the scientific literature on anguillids from the last four decades, analyzing research trends among and within species of the genus Anguilla. We identified a shift in research focus from largely biological towards more applied management and conservation topics, an increased emphasis on migration and fish passage considerations, and a tendency towards research on glass eels and silver eels over other life stages. We also identified a significant disparity in research effort between temperate species and tropical species, with a scarcity of knowledge on the latter. Finally, we described several key knowledge gaps about community-based interactions of eels, notably their roles as predator, prey, and ecosystem connector, and highlight opportunities for early career researchers to establish research programs within the field of anguillid research.