The sustainability of shrimp aquaculture: An emergy-based case study in the Gulf of Guayaquil thirty years later

As farmers increase production levels and expand their ponds, the aim of this research is to employ the emergy accounting methodology to assess the sustainability of Ecuadorean shrimp aquaculture in 2021 and compare these results to a previous study from 1991. Emergy accounting estimates the environmental support to any process in the biosphere according to the solar energy (solar emjoule sej) required for the production of products or services. After examining a typical shrimp farm in the Gulf of Guayaquil, this study found: 1) There is greater annual yield but no better emergy efficiency, nor more sustainability or less stress on the environment in comparison with a previous emergy analysis of shrimp farming in Ecuador in 1991. 2) Despite strong dependence on commercial feed, Ecuador's semi-intensive shrimp farming (10 individuals per m2) receives a large contribution of natural renewable resources (% Renew), which results in an overall emergy sustainability (ESI) that is similar to both extensive/organic and super-intensive culture systems in Brazil. 3) When shrimp farming in Ecuador is compared to other systems with commodities for export, it is found that systems with greater contribution from Nature over purchased resources (% Renew), as is the case of organic coffee culture in Peru, may become a more economically and environmentally desirable activity in the long-run. These findings reveal the decreasing sustainability trend within the current shrimp farming production system in Ecuador and encourages society to consider alternatives that do not underestimate the renewability of the inputs to the system.