Fish passes give endangered twaite shad chance to swim up River Severn and spawn

A twaite shad, which use only four British rivers to spawn and historically the Severn was the most important. Photograph: Canal & River Trust/PA

For nearly two centuries, one of Britain’s rarest fish has been shut out of its spawning grounds by large weirs.

But the endangered twaite shad has now returned to its historic spawning habitat on the River Severn, thanks to four new fish passes that enable the migratory fish to negotiate weirs and swim up river to lay eggs.