Beyond Description: A Size-Based Approach to Assess Intra and Inter-Specific Diet Overlap and Predator Foraging Behaviour

Size-based approaches have been recently used to describe and better understand general allometric patterns in predator-size prey-size relationships across piscivorous and teuthivorous fish species.  However most of these efforts have been primarily descriptive. Here, we will further develop this approach in novel ways to quantify size-based diet overlap and feeding behaviour using three case studies.  The first compares diets across predators from a size-based perspective to assess whether niche overlap is avoided when prey types overlap but predator-size prey size relationships differ.  The second uses predator-prey size scatters to infer foraging behaviour. The third quantifies similarities in intra-specific predator-size prey size relationships even when diets differ across populations to assess whether prey size is more constraining than prey type for some predators. These quantitative size-based approaches allow the incorporation of diets into predictions about ecosystem responses to exploitation and climate change, and provide critical linkages in multispecies and ecosystem models.