Pacific salmon and steelhead once contributed large amounts of marine-derived carbon, nitrogen, and phosphorus to freshwater ecosystems in the Pacific Northwest of the United States of America (California, Oregon, Washington, and Idaho).  Declines in historically abundant anadromous salmonid populations represent a significant loss of returning nutrients across a large spatial scale.  A paucity of marine derived nutrients in the Salmon River subbasin has been identified as a limiting factor to freshwater productivity and the growth and survival of resident and anadromous fishes (including four species listed as threatened or endangered under the Endangered Species Act).  We propose to mitigate diminished marine-derived nutrient inputs with experimental treatments using pathogen-free salmon carcass analogs and/or inorganic nutrients (silver bullets).  We will employ a randomized-treatment experimental design, similar to previously completed work by the Shoshone Bannock Tribes and other Columbia Basin cooperators, to assess the effectiveness of nutrient enrichment treatments in upper Salmon River subbasin streams.  Specific project objectives include: quantification of streamwater nutrient concentrations; stream nutrient limitation; stream nutrient cycling and retention; periphyton standing stock; macroinvertebrate density, biomass, and community composition; leaf litter decay rates, aquatic food web connections, and the growth and survival of resident and anadromous salmonids in treatment streams receiving nutrient additions and control streams that do not receive nutrient additions.