The Western and Central Pacific Ocean (WCPO) tuna fishery is the largest and one of the most productive in the world, contributing about 59% to the 2010 global tuna production. However, recent stock assessments showed a decreasing trend in the stock levels of big eye, yellowfin and skipjack tuna; and high fishing mortality of juvenile bigeye and yellowfin tuna, often caught along with adult skipjack. Major fishing states in the WCPO, including the Philippines, recognize the importance of addressing this ecological sustainability problem because it has an impact on their economies. Thus, policies have been implemented to address these problems. However, the result of these policies has been a mixture of successes and failures. An important reason for failure is the poor understanding of the behaviour of tuna fishery actors and the dynamics of tuna fishery system.
Fishery systems are complex adaptive systems, where fishermen behaviour is influenced by ecological, economic, social and political factors. This research aims to provide policy insights on what and how factors influence fisher behaviour towards economic and ecological sustainability of the tuna fishery through the use of Agent-Based Modelling (ABM). The project will also explore fishers’ response to direct regulations and market-based policies. In ABM, decision-makers are modelled explicitly as agents in a complex environment. As a result of nonlinear feedbacks between actors and their environment, ABMs typically display sensitivity to initial conditions, path-dependence and adaptability of actors. This makes their analysis rather challenging. This research will use sensitivity analysis to identify what factors are important in understanding fisher behaviour and its implications. Such factors provide promising opportunities for further investigation or as direct policy targets. The ABM structure will be based on key-informant interviews, regular stakeholder workshops, vessel records and industry reports.