Abstract
The combination of effective spawners in the parental generation (specifically the number of eggs deposited in spawning gravel) and survival (freshwater and marine) determines the number of sockeye salmon (Oncorhynchus nerka) that return (escapement, catch & en-route loss) to the Chilko-Chilcotin River (CCR) system in any given year. This chapter examines the array of biotic interactions and conditions, resulting from physical processes, which affect the smolt through adult stages of the life cycle. The quality and quantity of available habitat, combined with the complexities in timing of the sockeye salmon life cycle, leads to considerable inter-annual variation in sockeye salmon returns. The importance of smolt outmigration from Chilko Lake, ocean residence, and the return migration of adults are described in detail. A conceptual model is presented that connects ecosystem inputs and processes to the survival of sockeye salmon.
