Restoration of river connectivity enables long-distance spawning migrations in a potamodromous fish

• DOI: 10.1016/j.jenvman.2025.124646
• Publication Date: 2025-02-22T10:49:12Z
• Authors: Dagmara Błońska; Ali Serhan Tarkan; Demetra Andreou; Jonathan D. Bolland; Peter Davies; Jamie R. Dodd; Phillipa Gillingham; Catherine Gutmann...; Fatima Amat-Trigo; Sadi Aksu; Andrew Hindes; O. Jonas Palder; Mark Yeldham; J. Robert Britton

Rivers across the world are increasingly fragmented due to anthropogenic barriers, with restoration of connectivity often using fish passes. Fish passes are, however, usually designed for anadromous species, despite ecologically important non-anadromous species being present in communities impacted by fragmentation. To assess outcomes fishes installation multiple and weir modifications, movements potamodromous European barbel Barbus barbus were evaluated lower River Severn basin, western Britain, which was six weirs (two on a tributary, four mainstem). Movements individual measured long-life acoustic transmitters, stable isotope analysis assisting assessment variability movements. The three tagging groups measured: tagged 2015 (n = 19; no passes/modifications), 2018 tributary modified), 2020/21 20; all mainstem fitted passes). No group passed mainstem, approaches, only one most downstream during high water conditions winter. Following opening early 2021, individuals moved above via between April June (the spawning season). These then upstream up 110 km, some detected returning downstream. migrations potentially have ecological evolutionary significance, indicating that reconnection schemes also benefit fishes.