- Thesis (M.S., Natural Resources) -- University of Idaho, 2017 | Marine-derived nutrients (MDN) from spawning anadromous fish have received significant attention recently and are a model for understanding how migratory species transport resources across ecotones. Few studies report the role of species other than Pacific salmonids, despite evidence that watersheds were subsidized by resource pulses from multiple species. We explored the role of Pacific lamprey on stream food-webs using a stream productivity model, an evaluation of carcass fate in spawning ecosystems, and an experimental mesocosm to evaluate the response of juvenile salmon to carcass resources. We found that lampreys are unlikely to affect system-scale primary-productivity, but that carcasses may be local-scale resources to which juvenile stream fish may express a fine-scale behavioral response. These findings contribute to understandings of pulsed resources in streams and the role they play on consumers, with implications for restoration of migratory fish and ecosystems.