The role of the actors in the trade network structure of fishing products: The case of the shark market

In this paper we study the influence of the structure of relationships in the commercial network of fishery products in the economic performance and profits distribution among actors, taking the shark market in Mexico as a case study. For this, fishermen, permit holders and traders were interviewed in the local, regional and main markets for shark products in Mexico. With the information obtained, a weighted network of the shark market was built, the main centrality indices and the monetary contribution of each actor to the commercial system in terms of economic profits were calculated. Through a stepwise multiple regression analysis, the variables that positively affect economic profits were identified. Our results show that shark fin exporters obtain the highest net unitary profits, while traders of shark meat and fillet presented the highest net profits. The organization of the actors (type), the quantity traded (Kg), the out-degree and out-closeness are the variables that positively affect the economic performance of the shark market. These findings agree with standard economic networks theory about the consequences of competitive and monopolistic market structure on the distribution of the economic returns of the food commercialization. The quantitative analysis of weighted networks in the trade of shark products gives rise to new insights to understand how economic profits are generated and distributed in a commercial system and how the actors involved are favored by said activity.