D10.7: Storyline on Fishery pilot study

About this document This document presents a fisheries-focused storyline developed within the nextGEMS project, based on high-resolution Earth System simulations (HR-ESM). It examines the effects of climate change on West African marine ecosystems and fisheries, ranging from historical knowledge (CIMP) to new insights (HR-ESM). The storyline supports African-led policy initiatives, including the Blue Belt Initiative, African preparation for UNOC-3, and the SRFC Strategic Plan. Work package in charge WP10 Executive summary This document presents a science-informed storyline for the potential impacts of climate change on marine ecosystems and fisheries in the southern Canary Current Large Marine Ecosystem (sCCLME), developed within the framework of the EU-funded nextGEMS project. West African fisheries are undergoing profound transformations under the dual pressures of climate change and human exploitation. The region’s coastal ecosystems, particularly those within the southern Canary Current Large Marine Ecosystem (CCLME), are highly productive but increasingly vulnerable to shifting oceanographic conditions, warming waters, and declining upwelling intensity. Over the past decade, a series of landmark collaborative research programs have laid the foundation for understanding these dynamics and improving climate-resilient fisheries governance. By leveraging high-resolution storm-resolving Earth System Models (SR-ESMs) and deep learning algorithms, we reconstructed changes in sea surface chlorophyll-a (SSC) as a proxy for primary productivity. These outputs were linked to fisheries indicators such as small pelagic biomass and zooplankton prey fields using regionally calibrated ecological models and long-term acoustic observations. In this context, a storyline refers to a physically consistent, regionally grounded narrative that links projected ocean–climate conditions to ecological responses and fisheries impacts. It serves as a tool to translate complex simulations into decision-relevant information, and this deliverable reflects both scientific advances and the stakeholder co-development process that helped shape and interpret the results.Notably, early warning signals of ecosystem shifts have been detected in the region, underlining the urgency for adaptive management. Compared to coarse-resolution CMIP-based models, nextGEMS simulations provide enhanced spatial detail and more realistic scenarios for upwelling dynamics, mesoscale variability, and ecosystem stressors. These improvements make it possible to explore differential ecological responses (e.g., changes in distribution and productivity of Sardinella aurita), which were previously unresolved. However, significant uncertainties persist across all stages (from model inputs and AI reconstructions to biological species responses), necessitating sustained monitoring and iterative modelling to reduce these knowledge gaps. The storyline approach developed here translates complex climate and biogeochemical dynamics into a regionally relevant narrative that supports proactive governance. It does not offer prescriptive forecasts, but rather an exploratory framework to inform risk assessment, prioritise data gaps, and guide policy dialogue. This deliverable highlights novel outcomes from nextGEMS that go beyond previous initiatives, particularly in their use of SR-ESMs and AI-based ecological reconstructions. Through science-policy sessions, stakeholder workshops, and high-level consultations, the storyline has also been actively shared with regional institutions and decision-makers. Ultimately, it underscores the value of sustained co-development and calls for the institutionalisation of early warning systems and science-policy platforms to support climate-resilient fisheries strategies in Northwest Africa.