Predicting Trophic Interactions and Habitat Utilization in the California Current Ecosystem

Abstract

Abstract : While specifically focusing on trophic interactions affecting habitat utilization and foraging pattern of California sea lions (CSL) in the California Current Large Marine Ecosystem (CCLME), the long-term goal of our modeling approach is to better understand and characterize biological hotspots (i.e., the aggregation of multiple marine organisms over multiple trophic levels) off the U.S. west coast and in other regions where similar fully-coupled ecosystem models may be implemented. As such, our research represents a major step towards a predictive model that can provide fundamental knowledge about: (1) the spatial and temporal distribution of key marine organisms over multiple trophic levels, and (2) natural and anthropogenic variability in ecosystem structure and trophic interactions. The main research objective is to quantify habitat utilization and trophic interactions in the CCLME by considering patterns of covariability between environmental variables (e.g., temperature, primary production) and foraging patterns and success of middle (forage fish) and higher (sea lions) trophic level organisms. Since our numerical experiments are designed to isolate patterns of variability on seasonal to interannual timescales during normal and extreme years, we focus our analysis on identifying shifts in habitat utilization (e.g., shelf vs. offshore foraging) in the CCLME. We will also explore which features and environmental properties control foraging success in different sub-regions of the CCLME (e.g., onset and duration of upwelling season on the shelf, eddy variability).