Arizona biologists warn of Grand Canyon invasion after catching 3,000 invasive crayfish below Glen Canyon Dam

Arizona biologists warn of Grand Canyon invasion after catching 3,000 invasive crayfish below Glen Canyon Dam

Grand Canyon researchers are sounding the alarm after invasive crayfish numbers climbed sharply downstream of the Glen Canyon Dam, with worries that the species could reach some of the Southwest's remaining relatively pristine tributary streams. Experts fear they could put additional pressure on native fish, outdoor recreation, and a river system that communities across the region depend on. Here's what to know In a short stretch of the Colorado…