Smallmouth bass: The newest threat to Grand Canyon’s endangered fish
The day’s first gillnet haul of nonnative fish on lower Lake Powell was already alarming: three striped bass, three gizzard shad and a channel catfish. Any one of them or their offspring would be unwelcome intruders were they to slip through the massive concrete dam’s hydropower tubes and turbines to swim a few dozen miles downstream into the heart of Grand Canyon. Above Glen Canyon Dam, state fisheries managers in decades past would introduce alien species to support recreational angling on the lake. But below the dam, the fish could drift downstream to eat or outcompete Grand Canyon’s threatened humpback chub population, swelling the ranks of nonnatives that biologists are already battling.