Aquatic Inventory of the Upper Bill Williams Drainage, Yavapai and Mohave Counties, Arizona

The upper Bill Williams drainage in Yavapai and Mohave counties, Arizona, supports a diversified fauna of native and introduced fishes. Twenty-two species and two hybrids have been recorded from the upper drainage and Alamo Lake. Museum records were combined with collections from an intensive aquatic survey of the area to outline an account of the fish species that occur there. Patterns of distribution and abundance appear to be relatively stabilized with native fishes (Agosia chrysogaster, Rhinichthys osculus, Gila robusta, Catostomus insignis, and Pantosteus clarki) exclusively occupying the head waters, and introduced forms inhabiting lower reaches. Water quality of the upper basin was, with few exceptions, within levels outlined in federal and state surface water standards and found to support a variety of macroinvertebrates at high standing crop. Sixty-two total taxa were collected, including members of 9 of the 10 aquatic insect orders.