A protocol for the intercomparison of marine fishery and ecosystem models: Fish-MIP v1.0

Abstract

Geosci. Model Dev. Discuss., https://doi.org/10. 5194/gmd-2017-209 Manuscript under review for journal Geosci. Model Dev. Abstract. Model intercomparison studies in the climate and earth sciences communities have been crucial to build credibility and coherence for future projections. They have quantified variability among models, spurred model development, contrasted within-and among-model uncertainty, assessed model fits to historical data, and provided ensemble projections of future change under specified scenarios. Given the speed and magnitude of anthropogenic change in the marine environment, and consequent effects on food security, biodiversity, marine industries and society, the time is ripe for 15 similar comparisons among models of fisheries and marine ecosystems. Here, we describe the Intercomparison Project (ISIMIP), a cross-sectoral network of climate impact modellers. Given the complexity of the marine ecosystem, this class of models has substantial heterogeneity of purpose, scope, theoretical underpinning, processes considered, parameterizations, resolution (grain size) and spatial extent. This heterogeneity reflects the lack of a unified 20 understanding of the marine ecosystem, and implies that the assemblage of all models is more likely to include a greater number of relevant processes than is any single model. The current Fish-MIP protocol is designed to allow these heterogeneous models to be forced with common Earth System Model (ESM) CMIP5 outputs under prescribed scenarios for historic (from 1950s) and future (to 2100) time periods; it will be adapted to CMIP6 in future iterations. It also describes a standardized set of outputs for each participating Fish-MIP model to produce. This enables the broad characterization of 25 differences between, and uncertainties within, models and projections when assessing climate and fisheries impacts on marine ecosystems and the services they provide. The systematic generation, collation and comparison of results from Fish-MIP will inform understanding of the range of plausible changes in marine ecosystems, and improve our capacity to define and convey strengths and weaknesses of model-based advice on future states of marine ecosystems and fisheries. Ultimately, Fish-MIP represents a step towards bringing together the marine ecosystem modelling community to produce consistent 30 ensemble medium-and long-term projections of marine ecosystems.

Twenty‐first‐century climate change impacts on marine animal biomass and ecosystem structure across ocean basins

“…Historical (1970–2005) and future (2006–2100) projections of unfished global marine animal biomass (total animal biomass, biomass >10 cm, biomass 10–30 cm, and biomass >30 cm; vertebrates and invertebrates of trophic level >1, except for zooplankton) under different climate change scenarios were extracted from the Fisheries and Marine Ecosystem Model Intercomparison Project (Fish‐MIP v1.0; Tittensor, Eddy, et al, ; Data access: http://doi.org/10.5880/PIK.2018.005). The projections included outputs from six different global marine ecosystem models (Supporting Information Table S1): BOATS (Carozza et al, ; Carozza, Bianchi, & Galbraith, ), Macroecological (Jennings & Collingridge, ), DPBM (Blanchard et al, ), DBEM (Cheung et al, ), EcoOcean (Christensen et al, ), and APECOSM (Maury, ).…”

“…The projections included outputs from six different global marine ecosystem models (Supporting Information Table S1): BOATS (Carozza et al, ; Carozza, Bianchi, & Galbraith, ), Macroecological (Jennings & Collingridge, ), DPBM (Blanchard et al, ), DBEM (Cheung et al, ), EcoOcean (Christensen et al, ), and APECOSM (Maury, ). Each marine ecosystem model was forced with standardized output from two Earth system models (ESMs; Supporting Information Table S2) and greenhouse gas emissions scenarios (Representative Concentration Pathways, RCPs) following the Fish‐MIP simulation protocol (Tittensor, Eddy, et al, ). ESM outputs were derived from the CMIP5 database (https://esgf-node.llnl.gov/search/cmip5/) and bracketed a wide range of projected climate system changes, with GFDL‐ESM2M representing moderate and IPSL‐CM5A‐LR strong changes in, for example, sea surface temperature (SST) and oceanic net primary productivity (NPP) (Bopp et al, ).…”

“…As projections including fishing impacts were only available for three marine ecosystem models, and spatially explicit future fisheries projections are as yet unavailable, we chose to focus on runs under a no‐fishing scenario, thus isolating climate change effects on marine animal biomass (Tittensor, Eddy, et al, ).…”

“…To address this limitation, it is important to compare models and to combine them into ensemble projections, which can lead to a better understanding of the sources of uncertainty, provide more coherent projections to policy‐makers that properly account for this uncertainty, and thus advance the field of marine ecosystem modeling. While such comparisons are technically challenging, they can inform our understanding of the strengths and weaknesses of each modeling approach and help to guide further model improvements and ultimately improve projections of plausible futures (Schellnhuber, Frieler, & Kabat, ; Tittensor, Eddy, et al, ).…”

“…Here, we used models in the Fisheries and Marine Ecosystem Model Intercomparison Project (Fish‐MIP), an international network that brings together different marine ecosystem modeling approaches (Tittensor, Eddy, et al, ), to better understand and forecast long‐term climate change impacts on fisheries and marine ecosystems at ocean basin scales. Specifically, we analyzed how consistent or different mean trends and the spread of model projections were across ocean basins.…”