Abstract
Recent results indicate that density dependent processes in Atlantic salmon during early stages occur on spatial scales much smaller than those usually considered to be the spatial scale of populations and hence the units of population dynamics. However, the mechanism behind and consequences of this strong density dependence is poorly understood. The project aims to improve current understanding of how populations of Atlantic salmon are regulated through density dependent processes by testing the potential underlying mechanisms empirically. Two large-scale field experiments will be conducted that test whether energetic costs and/or predation costs due to high initial density are the mechanisms responsible for local density dependent survival. These and other data will be used to parameterize and existing spatially explicit behavior- and habitat-based population model to examine population consequences of habitat characteristics and behavioral decisions across environmental gradients. The model will be evaluated against a third large-scale field study that examine the importance of local vs. population scale density, and used as a tool for developing predictions relating 1. natural temporal and spatial variation in Atlantic salmon productivity, and 2. consequences of different management strategies for productivity under various environmental scenarios.
Norway