End-to-End Modeling: An Emerging Tool for Ecosystem-Based Fisheries Management

End-to-end models are receiving increasing attention as a quantitative tool for investigating marine ecosystem responses to climate variation and fisheries management. End-to-end models typically combine submodels of physics (hydrodynamics), lower trophic levels (nutrient-phytoplankton-zooplankton, NPZ), and upper trophic levels (fish, birds, fishers) into a single modeling framework. Such models are attractive because they can simulate a wide variety of effects, including ecosystem responses to interannual environmental variation, changes in fishing, and episodic and long-term trends in climate conditions. We present a 3-dimensional, fully coupled, sardine and anchovy model of the California Current that consists of four coupled submodels: hydrodynamics, Eulerian nitrogen-phytoplankton-zooplankton, individual-based full life cycle fish submodel, and an agent-based fishing fleet submodel. Our analysis demonstrates that the technology is available for developing and using 3-dimensional fully-coupled multispecies end-to-end models. We use the model to illustrate the features, challenges, and future directions in end-to-end modeling, as analyses expand from exploratory analyses to tactical management. The time is now for development and testing of these end-to-end models so we are ready with models of sufficient and documented confidence for wide-spread usage within the next decade.