Chemical treatment to be deployed against invasive fish in Colorado River
The National Park Service will renew efforts to rid an area of the Colorado River in northern Arizona of invasive fish by killing them with a chemical treatment, the agency said Friday. A substance lethal to fish but approved by federal environmental regulators called rotenone will be disseminated starting Aug. 26. It’s the latest tactic in an ongoing struggle to keep non-native smallmouth bass and green sunfish at bay below the Glen Canyon Dam and to protect a threatened native fish, the humpback chub. The treatment will require a weekend closure of the Colorado River slough, a cobble bar area…