Total fish standing crop data from 79 North American streams located in Wyoming (N = 20), Vermont (N = 19), Florida (N = 15), Iowa (N = 12), Ontario (N = 10), Washington (N = 2), and Missouri (N = 1) were used to test the hypothesis that stream fertility as indexed by total phosphorus concentrations is an important environmental factor influencing fish standing crop. Total fish standing crop among the different geographical regions was not related to differences in latitude, but regional estimates of average fish standing crop were significantly correlated to total phosphorus concentrations (r = 0.79, p < 0.05, n=7). The best-fit empirical regression model for these data was: