Freshwater ecosystems are closely linked to human activity, since most of the world’s industry and agriculture are concentrated alongside flowing waters. Some 126,000 species, including half the world’s 30,000 fish species, inhabit those waters. For years they have been paying the price of proximity, vanishing four to six times as fast as those on land or at sea. In the U.S., nearly half of all endangered species live in fresh water.
There is hope, however: captive-breeding programs. Waterways in the American Southeast are choked by dams and clouded with pollutants, yet many still abound with diverse species, like the spotted darter that swims in West Virginia’s Elk River. To preserve and restore this freshwater life-including the Ouachita madtom of Arkansas’s Saline River-researchers are building what amount to "arks," or seed stock. That means capturing and breeding species, reintroducing them once habitats are clean, then monitoring them-sometimes by unusual means. To check on a catfish called the smoky madtom, for instance, scientists in Tennessee’s Abrams Creek snorkel as they search under rocks.
Success stories are already starting to flow in from such nascent programs, offering a breath of life and a stream of hope.