Community-level approaches (i.e. diversity, abundance, Bray-Curtis, etc.) are traditionally used when conducting bioassessments with benthic invertebrates. In this study on pulp mill (PME) and sewage effluents, we examined the utility of invertebrate population endpoints because of disagreements in the interpretation of fish population and invertebrate community data from previous studies at these sites (Galloway et al. 2003; Culp et al. 2003). We sampled larval stoneflies, Acroneuria sp. (Perlidae) and compared their responses [growth (head capsule width, etc), development (wingpad length), and fecundity (gonad weight)] to similar endpoints in a resident fish species, Slimy sculpin (Cottus cognatus). In the summer of 2006 we found an abundance of fish responses to sewage inputs, but not to PME. The stoneflies also showed the same pattern of responses with large impacts downstream of sewage discharges and an absence of effects downstream of the pulp mill outfall. In many cases the effects in stoneflies were more dramatic than in fish. Our findings support the use of invertebrate population assessments as an alternative method in environmental monitoring programs.