Cooperative Fish and Wildlife Research Units Program: Colorado
Education, Research and Technical Assistance for Managing Our Natural Resources

A key strategic science question (SSQ 1-8, Grand Canyon Monitoring and Research Center, 2007) is how can native and nonnative fishes best be monitored while minimizing repeated handling of fish. Managers wish to obtain population information in the least intrusive manner possible, especially when sampling the endangered HBC. Remote PIT-tag antennae have been shown to be very effective at continuous monitoring in other, generally smaller rivers and streams, alleviating the need for additional field sampling trips and multiple fish handling events. We propose to evaluate the efficiency of hoop-netting used for current monitoring compared to that of the new remote PIT tag antenna array, that does not require repeated handling of fishes, or additional field sampling in the Little Colorado River (LCR). PIT tags are already implanted in a large fraction of the adult population and to a lesser degree in the smaller life history stages of HBC in Grand Canyon. Antennae provide the opportunity to evaluate gear efficiency of hoop nets (e.g. what proportions of the fish present are captured), to increase precision of population estimates, direction and timing of movement within the LCR, and presence of fish in the LCR year round.