Area-based management has been promoted to mitigate risks beyond the boundaries of aquaculture farms. However, there remains no objective measure of the scale at which area-based management can most effectively control systemic production risks. There is also a lack of understanding of how the social connectivity between farmers operating in a given landscape or ‘area’ affects the shared risk perceptions and strategies of shrimp farmers. This paper addresses this gap by introducing a socio-spatial index (SSI) that enables the objective definition of area-based management based on the spatial extent of the social connectivity of shrimp farmers. The study explores how the SSI translates into individual and shared risk behaviour by using structural equation modelling. The results indicate that the SSI provides a generic measure for the socio-spatial extent of area-based aquaculture management and a specific means of determining the probability of farmers adopting shared mitigation strategies related to key risks like disease. The SSI provides the assessment and further development of spatially explicit risk management strategies for promoting responsible aquaculture production.