Habitat fragmentation is a major source of biodiversity loss in freshwaters, with rivers around the world fragmented by dams and weirs that create impoundments. These impoundments restrict river longitudinal connectivity, inhibit fish migrations across ecosystem boundaries (marine-freshwater), prevent lifecycle completion, modify gene-flow and impact population sustainability. Whilst restoring longitudinal connectivity can be achieved via ‘fish-passes’ on the impoundments, these only favour movements of salmonid fishes. Increasingly, impoundment removal is used as the holistic alternative. There have, however, been few attempts to quantify its conservation and ecological outcomes for non-salmonid migratory fishes, despite these species facing unprecedented European population declines,