For almost a century, migratory flyways have been a cornerstone of bird conservation. Knowing where these aerial highways are helps protect habitats and monitor species through carefully mapped routes that connect breeding, feeding and resting grounds.
But birds aren’t the only kinds of animals taking vast treks. Freshwater fish do, too.
Unlike birds, whose flight paths are visible to the naked eye, these fish migrations remain hidden beneath the surfaces of rivers. This invisibility has left them largely overlooked, even as migratory freshwater fish populations worldwide have plummeted by more than 80 percent since 1970. Habitat fragmentation, overfishing and pollution have taken a devastating toll on species essential to aquatic