Protecting Migratory Fish: Welfare and Conservation at River Barriers

Migratory fish including salmon, sea trout, and eels face massive mortality and welfare harm at river barriers. Fish passage solutions benefit both conservation and individual fish welfare.

Key Facts

An estimated 95% of migratory fish habitat in Europe has been lost due to river damming, weirs, and other barriers preventing upstream migration
Atlantic salmon must complete upstream migration to reach spawning grounds — barriers that prevent or delay passage cause exhaustion, injury, and breeding failure
Fish passes (fishways) allow migratory fish to bypass barriers — their effectiveness varies significantly with design and flow conditions
European eels are critically endangered partly due to mortality at turbine impellers and pumping stations — downstream eel passage screens and trap-and-transport programmes provide partial mitigation
The physiological stress of repeated barrier encounter — including futile jumping attempts at impassable weirs — causes measurable welfare harm in migrating fish
River restoration including barrier removal is increasingly recognised as the most effective intervention for migratory fish conservation and welfare
The UK's Barrier Removal for England (BARET) and equivalent Scottish programmes aim to remove or modify hundreds of obsolete barriers to restore fish passage

Welfare Considerations

The welfare dimension of fish passage is real and significant. Salmon and sea trout attempting to navigate impassable barriers make repeated jumping attempts against hard surfaces, causing physical injury and extreme exhaustion. The prolonged delay at barriers during the critical spawning migration period creates a physiological welfare burden — fish deteriorate physically as they wait for flow conditions or spend energy on futile upstream attempts. Beyond the individual welfare harm, the population-level consequences of barrier mortality reduce future fish populations, eliminating the welfare of generations of animals who would otherwise exist. Fish passage solutions — from effective fish ladders to complete barrier removal — provide both conservation and individual welfare benefits that justify substantial investment.

What You Can Do

Support the Wild Trout Trust, Atlantic Salmon Trust, and Salmon and Trout Conservation campaigns for river barrier removal and fish passage improvement
Engage with the Environment Agency and SEPA on fish passage requirements for any river development or infrastructure maintenance affecting fish movement
Advocate for the removal of obsolete river barriers including historic mill weirs and other structures with no remaining economic function
Donate to river restoration organisations working on barrier surveys, fish pass design, and barrier removal programmes
Raise awareness of the connectivity needs of migratory fish — most people are unaware that river barriers cause both welfare harm and conservation damage to migrating fish
Support farming practices that reduce agricultural runoff into rivers — poor water quality impairs fish welfare and migration success independently of physical barriers
Push for mandatory fish passage assessment at all new and existing river infrastructure including flood defences and water management structures