Effects of cooperation and different characteristics of Marine Protected Areas in a simulated small-scale fishery

Marine fisheries are a critically important source of food, nutrition, and employment for millions of people. As the global population increases, new and expanding pressures are created on fish resources. Marine Protected Areas (MPAs) have been widely promoted as valuable tools for rebuilding or maintaining fish stocks around the world. The success of MPAs, however, widely depends on their particular configuration and management and their effectiveness is often object of contentious debates in both scientific and political arenas. Since fisheries management is a collective action problem, some forms of human cooperation in terms of fishing behaviour can lead to sustainable fisheries and can represent, in theory, a complementary or even an alternative approach to the establishment of no-take marine reserves. We present here a new Agent-Based Model (ABM) that captures the main characteristics of an idealised small-scale fishery. We then use the model to investigate the combined effects of different fishing strategies (expressed by a cooperative trait associated to fishing effort) and various configurations of no-take reserves (including presence or absence of MPA, size of MPA, age of MPA, i.e. time elapsed since its establisment, and distance between two MPAs) on fish abundance and catch under an overfishing regime. Our results show that high cooperation without an MPA can be as effective as lower levels of cooperation combined with an MPA in maintaining fish stocks and catches at relatively high levels. The mobility of our fish agents implies that, contrary to current belief, these results may not be limited to sedentary species. We also found that the greatest impacts on fish abundance and catch are produced by the size of an MPA and the time elapsed since its establishment. Furthermore, the distance between two MPAs has no significant effect, regardless of the cooperation levels characterising the fishing agents. Despite its simplicity, the ABM presented here provides insights on the most plausible effects that combinations of different MPA designs and human cooperation strategies can produce on overexploited small-scale fisheries. When appropriately adapted with a realistic, fishery-specific parameterisation, this model can constitute a valuable tool for evaluating the impact of different resource management strategies. We make the model available as open-source software with the aims of fostering reproducibility, transparency, and flow of ideas.