A Theoretical Framework for Ecosystem-Based Management of Shared Demersal Fish Stocks in the Gulf of Guinea: Integrating Socio-Ecological System Theory with Fisheries Dynamics

Ecosystem-based fisheries management in multi-jurisdictional shared stock systems requires theoretical frameworks that reconcile ecological complexity with institutional governance realities. This research develops an original socio-ecological system theory-informed framework for managing shared demersal fish stocks in the Gulf of Guinea, integrating Ostrom's design principles with the Ecopath with Ecosim ecosystem modelling platform. The framework is constructed through three linked components: a multi-species biomass dynamic model parameterised with original trawl survey data; an adaptive governance analysis of existing bilateral and multilateral fisheries arrangements among Nigeria, Benin, and Togo; and a participatory stakeholder scenario analysis of alternative management trajectories. The theoretical contribution centres on a formalised feedback architecture connecting ecological state indicators to governance response thresholds, which the study terms the Ecological-Institutional Feedback Loop model. Ecosystem modelling incorporating 22 functional groups reveals strong trophic couplings between small pelagics and demersal species, implying that single-species management systematically fails to capture indirect effects. Governance analysis identifies the absence of binding transboundary stock assessment protocols as the primary institutional failure. Stakeholder scenario modelling demonstrates that coordinated harvest reductions of 25 percent under the proposed framework would increase long-run profitability compared to current trajectories for all stakeholder groups. The framework advances ecological theory by embedding institutional adaptation mechanisms within a food web model, creating the first dynamic governance-ecology coupling for West African shared stocks. The study calls for adoption of the framework within the Gulf of Guinea Commission's fisheries working group. Keywords: ecosystem-based management, socio-ecological systems, Gulf of Guinea, shared stocks, Ostrom.