My postdoc was spent looking at hybridization between humpback (Gila cypha, above) and roundtail (G. robusta) chub in the Colorado river system (see here for a publication that stemmed from that - perhaps sometime I'll post on that work). My fieldwork was at the confluence of the Colorado and Little Colorado rivers where we'd capture, measure, tag & photo the fish. Thus, I'm happy to report the following:
The humpback chub, a closely watched indicator of the Grand Canyon's ecological health, has grown steadily in number since 2001 as changing conditions on the Colorado River have created a more hospitable habitat.
The population of the endangered fish grew by 50 percent over the past eight years, the U.S. Geological Survey reported Monday. By the end of last year, there were an estimated 7,650 adult chub, fish at least 4 years old, near the confluence of the Colorado and Little Colorado rivers. That's up from about 4,000 fish as recently as 2000.