This report summarizes and compares the physical characteristics of nine streams within five watersheds (Firebag, Muskeg, Steepbank, MacKay, and Ells) in the AOSERP study area. The distributions and relative abundances of fish in each stream and watershed are also described and related to the physical characteristics that tend to promote or limit sport fish production. The system of reach classification and biophysical measurements developed by Chamberlin and Humphries (1977) was used throughout the present study. The detailed results of this study are presented in the accompanying atlas that forms Volume II of this report (Walder et al. 1980). From 16 to 24 species of fish were found in each watershed. Forage fish (lake chub, pearl dace, longnose dace, trout-perch, brook stickleback, slimy sculpin) and white and longnose suckers were the most abundant fish in every stream or river studied. The most important and widespread sport fish present were (in order of decreasing abundance) arctic grayling, northern pike, and walleye. Other species of sport fish (burbot, lake whitefish, mountain whitefish, yellow perch, Dolly Varden, and goldeye) were found in small numbers, and were almost always confined to the lower reaches of the rivers in proximity to the Athabasca River. A good correlation was found between physical characteristics of streams and the distributions and abundances of fish. Present information suggests that the following general ratings for sport fish potential can be applied to the five watersheds that were studied: Firebag River watershed, excellent; Muskeg River watershed, poor to moderate; Steepbank River, moderate; MacKay River watershed, poor to possibly moderate; and Ells River, excellent. These ratings are based only-on comparisons among the studied watersheds; they do not consider productivity of other watersheds within or beyond the boundaries of the AOSERP study area.