Trophic dynamics, growth and survival of juvenile salmon in coastal lake and marine ecosystems

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Pacific salmon are an important fisheries resource for Canada and the Pacific rim countries, with significant links to both regional and national economies, and social and cultural heritage of costal communities and First Nations. In recent decades the productivity of Pacific salmon has been declining, with several stocks all but disappearing. Although the underlying mechanisms are still unclear, there is a growing sense that such declines may be linked to the variability in temperature, nutrients, the quantity and quality of zooplankton, forage fish and predator assemblages in coastal marine and freshwater ecosystems. Currently there are significant uncertainties in the prediction and forecast of annual adult salmon returns, which can lead to significant loss of business and negative socio-economic consequences for coastal communities. I propose to understand and model the large-scale variability in feeding, foodweb and resource ecology of juvenile salmon at the scale of coastal Pacific ecosystems of BC. It is critical to improving Canada's ability to forecast and predict the growth, survival and associated adult returns of Pacific salmon with greater confidence. I also propose to identify the major processes that determine size- and age-distribution of sockeye fry in 10-12 sockeye lakes, and test how other cohabiting zooplanktivores (e.g. stickleback and Mysis) alter foodwebs and resource partitioning by sockeye fry. We hypothesized that variable lake or ocean conditions through shifts in the quality and quantity of prey may affect foodweb dynamics, trophic interactions and diet overlaps within and among species as a function of size, and eventually leading to variable growth and survival of juvenile Pacific salmon. This research program is expected to produce new insights and better understanding of foodweb dynamics and trophic interactions of juvenile Pacific salmon, which will lead to better management strategies for one of Canada's precious natural resources.