SPRAT: A spatially-explicit marine ecosystem model based on population balance equations

Authored by Arne N Johanson, Andreas Oschlies, Wilhelm Hasselbring, Boris Worm

Date Published: 2017

DOI: 10.1016/j.ecolmodel.2017.01.020

Sponsors: No sponsors listed

Platforms: No platforms listed

Model Documentation: ODD Mathematical description

Model Code URLs: Model code not found

Abstract

To successfully manage marine fisheries using an ecosystem-based approach, long-term predictions of fish stock development considering changing environmental conditions are necessary. Such predictions can be provided by end-to-end ecosystem models, which couple existing physical and biogeochemical ocean models with newly developed spatially-explicit fish stock models. Typically, individual-based models (IBMs) and models based on advection-diffusion-reaction (ADR) equations are employed for the fish stock models. In this paper, we present a novel fish stock model called SPRAT for end-to-end ecosystem modeling based on population balance equations (PBEs) that combines the advantages of IBMs and ADR models while avoiding their main drawbacks. SPRAT accomplishes this by describing the modeled ecosystem processes from the perspective of individuals while still being based on partial differential equations. We apply the SPRAT model to explore a well-documented regime shift observed on the eastern Scotian Shelf in the 1990s from a cod-dominated to a herring-dominated ecosystem. Model simulations are able to reconcile the observed multitrophic dynamics with documented changes in both fishing pressure and water temperature, followed by a predator-prey reversal that may have impeded recovery of depleted cod stocks. We conclude that our model can be used to generate new hypotheses and test ideas about spatially interacting fish populations, and their joint responses to both environmental and fisheries forcing. (C) 2017 Elsevier B.V. All rights reserved.

Tags

Dynamics global change fisheries Climate-change Food webs Size-spectrum End-to-end Pelagic fish Cod Atlantic End-to-end modeling Population balance equation Fish stock prediction Ecosystem-based management