A Life-Cycle Modeling Approach to Investigate Cumulative Effects on Fraser River Sockeye Salmon Dynamics

In recent decades, the productivity of many Fraser River Sockeye Salmon (Oncorhynchus nerka) populations has declined, reaching record lows in 2009. Interestingly, over the same period, one population has exhibited substantial growth, while a few others have not exhibited any systematic trends. More recently (2010-2014), Fraser River Sockeye Salmon productivity has improved. Cumulative effects within and across life stages have been suggested as major factors influencing the dynamics of Fraser River Sockeye Salmon populations. This research will use life-cycle models to investigate the influence of cumulative effects on the dynamics of 18 Fraser River Sockeye Salmon conservation units (CUs), which are comprised of one or more populations. The models will be parameterized using data sets collected by various agencies over the past 50 years and by academic partners over the last decade. We will use modern statistical methods in model parameterization, including integrated, multi-level and state-space modeling approaches. Stochastic simulations of these models will be used to assess how potential management responses could influence the abundance and status of the CUs. Our research will generate invaluable results and tools to assess how cumulative effects and management actions will influence the future sustainability and diversity of Fraser River Sockeye Salmon CUs.