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.' L. the incidence of infestation was 55 % (Carothers and Minckley 1980) Carothers et al., in press}. As the impact of this exotic parasite has been shown to be devastating to other native fishes (Wilson et ala 1966, James 196s), its. continued presence in the Little Colorado population of the humpback chubs represents an i~~ediate problem and should be monitored closely. Summar~ ---- The following observations were made during this survey. 1. Reproduction occurred in the humpback chub population during 1979, as confirmed by the collection of young- of-the-year fish. 2. More than ten year classes of fish were present in the July collections, with y~ar' classes IV and IX or older predominating. 3. Relative densities were comparable to previous data, although lower than '1978 values in upstream areas. 4. In terms of relative ablmd~nce, the humpback chub was the most common fish collected followed by the flannel- mouth sucker, speckled dace, carp, and channel catfish. 5. Sixty-seven humpback chubs were tagged and released. No recaptures were obtained. 6. Behavioral observations suggested that this species may exhibit some size segregation when schooling. 7. The anchon~orm parasite was still present, but in much lower numbers than previously observed. Acknowledgements ---- Funding for this survey was provided by the Office of Endangered Species, Region II. Their assistance is appreciated. lVJr. Terry McCall, Arizona Game and Fish Department is thanked for providing field assistance as are ~~. Sam West and ~tr. John Thomas, National Park Service, Grand Canyon. The National Park Service, Grand Canyon and the Navajo Nation are also thanked for allowing access to the area.