Effects of Kokanee Salmon (<i>Oncorhynchus nerka</i>) Decomposition on the Ecology of a Subalpine Stream

Abstract

The role of kokanee salmon (Oncorhynchus nerka) carcass decomposition in the nutrient cycles and energy flow of a subalpine stream was investigated during a season (1970–71) of high spawner abundance and a season (1972–73) of low spawner abundance with a December storm flushing the stream of carcasses. Primary production, periphyton biomass, heterotrophic activity, and nutrient concentrations were greater downstream than upstream during the peak carcass decomposition of 1971, whereas they were the same at other times of that year and in 1972–73. Calculations showed that upstream–downstream differences in phosphate could be accounted for by the salmon carcasses.