Sustainable intensification of small-scale aquaculture systems depends on the local context and characteristics of producers

Abstract: Aquaculture has been the fastest growing food production sector globally due to its potential to improve food security, stimulate economic growth, and reduce poverty. Its rapid development has been linked to sustainability challenges, many of which are still unresolved and poorly understood. Small-scale producers account for an increasing fraction of aquacultural output. At the same time, many of these producers experience poverty, food insecurity, and rely on unimproved production practices. We develop a stylized mathematical model to explore the effects of ecological, social, and economic factors on the dynamics of a small-scale pond aquaculture system. Using analytical and numerical methods, we explore the stability, asymptotic dynamics, and bifurcations of the model. Depending on the characteristics of the system, the model exhibits one of three distinct configurations: monostability with a global poverty trap in a nutrient-dominated or fish-dominated system; bistability with poverty trap and well-being attractors; multistability with poverty trap and two well-being attractors with different characteristics. The model results show that intensification can be sustainable only if it takes into account the local social-ecological context. In addition, the heterogeneity of small-scale aquaculture producers matters, as the effects of intensification can be unevenly distributed among them. Finally, more is not always better because too high nutrient input or productivity can lead to a suboptimal attractor or system collapse.