Evolution of the global seafood trade network and regional vulnerabilities to shocks
Food systems are increasingly global and seafood is among the most highly traded commodities. Global trade allows countries to overcome regional shocks to food supply, but reliance on international food trade exposes countries to higher risks from external perturbations. Countries which are nutritionally- or economically-dependent on international trade of a commodity may therefore be adversely affected by such perturbations. Both the benefits and risks associated with international trade are tied to the structure of the trade network. We characterized the evolution of the global seafood trade network and modeled environmental and policy perturbations (e.g. fishery collapse, natural disaster, or export ban) in order to identify regions most vulnerable to shocks. Network analysis methods were applied to bilateral trade data to quantify changes in network connectivity and structure. Shock propagation was then modelled based on the seafood trade network structure and gross domestic product. We assessed vulnerability to shocks in the network by comparing changes in national fish supplies to indices of nutritional fish dependency.
From 1994 to 2012 there was an 80% increase in the average number of trade partnerships and the total value of traded seafood increased by a factor of 2.6. These changes indicate an increasing globalization of seafood products. Additionally, across the network we found: increased influence of Thailand and China, strengthened intraregional trade, and increased exports from South America and Asia. This quantification of the structure over time suggests future changes in the network and identifies influential countries that may be important for deriving future environmental and food security benefits. By modelling shocks in the network, we found that: 1) net exporters are most exposed to shocks, 2) Northern Europe and Eastern and Southeast Asia have the most significant influence on the network, and 3) Central and West Africa are the most vulnerable to shocks within the network. Establishing the global seafood network provides a way to assess changes in the intensity and distribution of food harvest from aquatic systems. Understanding how shocks are transmitted identifies regions with the highest vulnerability to diminished food security within the seafood commodity trade network. Further development and extension of the analysis presented is an important step in building a more resilient food system.