A large native fish of the Colorado River Basin that looks unlike almost any other freshwater fish in the American Southwest. Its signature feature is the tall, sharp “razorback” hump (a raised ridge/keel) running along its back between the head and dorsal fin—an odd, almost prehistoric shape that makes it instantly recognizable. Adults can grow quite large, and they’re built for big-river life: strong-bodied, with a downturned mouth suited for feeding along the bottom. Long ago, this body shape likely helped it handle powerful currents and murky water, and the hump may have helped protect it from predators that tried to swallow it (imagine trying to gulp down a fish with a built-in “spiny roof”). Today, though, the razorback’s biggest challenge isn’t natural predators—it’s surviving in a river system that humans have dramatically reshaped.

Historically, razorback suckers lived across much of the Colorado River system, but they’re now restricted to far fewer places, including stretches of the Colorado River and a handful of big reservoirs. They use different habitats at different life stages: adults can survive in deep water and reservoirs, but successful reproduction depends on access to suitable spawning areas and, most importantly, on young fish surviving long enough to join the adult population. That “youth survival” piece is the core problem. In many remaining populations, adults still spawn, but the babies and juveniles often don’t make it to adulthood—biologists call this lack of “recruitment,” basically meaning not enough youngsters grow up to replace older fish.

So why is it so hard for baby Razorbacks to grow up? A big reason is that the Colorado River Basin now contains many non-native predator fish that weren’t part of the razorback sucker’s original world, and young razorbacks are especially easy targets. Add in dams, altered river flows, and habitat changes, and the result is a fish that can still reproduce, yet can’t reliably complete its life cycle in the wild. The razorback sucker was listed as endangered in 1991, and while conservation work has created some promising pockets—places where populations are surviving and spawning—the species still needs broader, consistent wild survival of young fish to truly recover.

Distribution

Country

Population est.

Status

Year

Comments

Mexico

Official estimate

EX

Extinct locally

United States

2012