Fish Ladders and River Connectivity: Welfare and Conservation Benefits

Fish passage structures that allow migratory fish to navigate dams and weirs provide both welfare benefits for individual fish and conservation benefits for wild populations.

Key Facts

An estimated 60% of major rivers globally are fragmented by dams, weirs and other barriers to fish migration
Atlantic salmon and sea trout require access to upriver spawning grounds and face exhaustion and mortality at impassable barriers
Fish ladders are stepped pool structures allowing fish to ascend barriers in stages matching their swimming capacity
Nature-like bypass channels are increasingly preferred over traditional ladder designs for their greater species inclusivity
Failed migration attempts at barriers cause physical exhaustion, injury and mortality in individual fish
Successful dam removal is the most effective fish passage solution and has restored salmon runs in multiple river systems
Monitoring fish ladder efficiency reveals that poorly designed structures may be passed by less than 10% of approaching fish

Welfare Considerations

For migratory fish species, barriers to upstream movement represent a welfare problem at multiple levels. Individual fish experience exhaustion, injury and death attempting to pass impassable barriers. For species like salmon that do not feed during spawning migrations, every failed passage attempt depletes finite energy reserves. Successfully designed fish passage structures reduce this welfare cost by providing navigable routes, though passage efficiency varies widely between designs and species. The ultimate welfare and conservation solution is dam removal, which has demonstrated dramatic recovery of both fish populations and individual fish welfare outcomes in rivers across Europe and North America.

What You Can Do

Support river restoration organisations campaigning for dam removal and improved fish passage
Advocate for fish passage requirements to be included in water management planning and dam licensing
Choose electricity from providers that do not source from hydroelectric facilities without fish passage infrastructure
Donate to monitoring programmes that assess fish passage structure effectiveness
Raise awareness of river connectivity as an animal welfare issue alongside its conservation framing