Mean whole-body concentrations of Hg in individual prey-fish species varied from 24 to 58 ng/g wet weight in Grand Portage Creek (two species), from 49 to 91 ng/g in Poplar Creek (five species), and from 50 to 63 ng/g in the lower reach of Snow Creek (four species) (Table 5). In the beaver pond at upper Snow Creek, the concentration of Hg averaged 35 ng/g in the central mudminnow, the only species obtained from that site in sufficient numbers for statistical estimation. Species means for whole fish within individual stream sites ranged from 24 ng/g wet weight in slimy sculpin to 91 ng/g in blacknose dace and longnose dace. In axial fillets, concentrations of total Hg averaged 40 ng/g wet weight in rainbow trout from Grand Portage Creek, ranging from 23 to 69 ng/g in individual fish (Table 5). Concentrations were higher in fillets of creek chub from Poplar Creek, averaging 91 ng/g and ranging from 54 to 168 ng/g.