being made to manage water flows from Lake Powell to benefit humpback chub, and research is also being conducted into ways of controlling introduced fish in those areas where juvenile humpback chub live.
The Little Colorado River enters the mainstem Colorado River in Grand Canyon National Park about 80 miles below Lake Powell. The lower 8 miles of the Little Colorado River is the main spawning site for humpback chub and is an extremely rugged and remote area accessible only by boat, helicopter or rigorous hiking.
Each spring researchers set hoop nets in the lower 1,200 meters of the Little Colorado River to catch and mark these unique fish. Captured fish are measured and scanned for the presence of a PIT tag and then released. PIT tags are small electronic tags about the size of a rice grain that are implanted within the fish. When a tagged fish is recaptured and scanned, a distinct number is revealed which researchers can use to estimate how many fish are left in the population and how many new fish have been born. Measurements on water flow and water temperature are also recorded as are catch rates of the other fish species that are present. All of this information is used to evaluate trends in humpback chub population size. This research is part of a long-term monitoring project for native fish which began in 1987.