The Eel Ascending: The Influence of Lateral Slope, Climbing Substrate and Flow Rate on Eel Pass Performance

• Published in: Fishes
• Main Authors: Adam T. Piper, Paula J. Rosewarne, Charlotte Pike, Rosalind M. Wright
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI AG 2023
• Subjects: European eel; Anguilla anguilla; fish passage facilities; fish behaviour; eel fishway; climbing substrate; Biology (General); QH301-705.5; Genetics; QH426-470
• Online Access: https://doi.org/10.3390/fishes8120612; https://doaj.org/article/2523054f573b45099925295bc9a7c6a4

Optimising the design of passage facilities to restore fluvial connectivity for juvenile European eel ( Anguilla anguilla ) is a key priority within conservation efforts for the species, across the majority of its freshwater range. Employing an experimental setup that simulated gravity-fed upstream eel passes, this study demonstrated that novel V-profile passes, which incorporate two lateral slopes (15°), performed better than laterally flat passes over the flow rates tested (0.2–0.6 L s −1 ). For the small eel size used (60–80 mm length), the bristle substrate consistently outperformed studs, but the lateral slope had a greater effect on passage metrics than the substrate choice. Our findings strongly support the use of V-shaped channels for upstream migrating eel at fish passage facilities, particularly in scenarios where flow rates may be elevated and/or fluctuating, such as for gravity-fed passes.