Applying Agent-Based Modelling to Simulate Fisher Behaviour and Emergent Stock Dynamics in the Artisanal Fisheries of the South South Zone

This research applied agent-based modelling to simulate the behavioural decisions of artisanal fishers and the emergent population dynamics of target fish stocks in coastal fisheries systems of Nigeria's South South geopolitical zone, covering Rivers, Bayelsa, Delta, Edo, Akwa Ibom, and Cross River states. Traditional fisheries stock assessment models treat fishing effort as an aggregate variable, failing to capture the heterogeneous, adaptive responses of individual fishers to ecological conditions, market signals, and social influences. An agent-based model was constructed in the NetLogo simulation environment, incorporating fisher agents with adaptive behaviour rules governing target species selection, gear choice, spatial effort allocation, and exit-from-fishing decisions. Fish stock agents followed age-structured population dynamics calibrated from available stock assessment data. The model was parameterised and validated against 10 years of disaggregated landing data. Scenario simulations examined the emergent consequences of gear restrictions, closed seasons, and alternative income programmes on stock recovery trajectories. Results demonstrated complex nonlinear relationships between individual fisher adaptation and population-level outcomes. Gear restriction policies produced rapid short-term effort displacement to unregulated areas, counteracting intended stock recovery effects. Closed season policies achieved greater stock recovery when coupled with alternative income support that reduced re-entry incentives. Social network connectivity among fishers was a critical model parameter, with high connectivity amplifying both positive and negative collective responses to management signals. The study demonstrates the original application of agent-based modelling to Nigerian coastal fisheries and recommends its adoption as a supplementary scenario planning tool within regional fisheries management frameworks. Keywords: agent-based modelling, fisher behaviour, stock dynamics, South South Nigeria, fisheries simulation