Anguillid eels as a surrogate species for conservation of freshwater biodiversity in Japan

Anguillid eels, including the Japanese eel (Anguilla japonica) and giant mottled eel (A. marmorata), serve as effective surrogate species for conserving freshwater biodiversity in Japan. These eels, being widespread across river systems and high-order predators, exhibit a significant positive correlation with the density of other diadromous species. However, this relationship is indirectly linked to river-ocean connectivity, as both eel density and diadromous species abundance decrease with distance from the river mouth and cumulative height of trans-river structures. The study, conducted across 78 sites in six rivers in mainland Japan and Amami-Oshima Island, used stable isotopic analyses and optimal modeling to assess these relationships, highlighting the potential of anguillid eels as indicators, umbrella, and flagship species for freshwater biodiversity conservation.

Itakura, H., Wakiya, R., Gollock, M., & Kaifu, K. (2020). Anguillid eels as a surrogate species for conservation of freshwater biodiversity in Japan. Scientific Reports, 10(1). https://doi.org/10.1038/s41598-020-65883-4