Abstract

Emergy analysis is a thermodynamically based approach to assess the performance of systems and it is a useful tool for environmental decision-making. The kelp resource (Lessonia nigrescens Bory) is the basis for one of the main benthic fisheries of northern Chile, in both economic and social terms. The Atacama coastal kelp fishery is most important at the national level. To better understand the long-term changes in the environmental and socioeconomic factors that govern the sustainability of the resource, emergy synthesis was used to evaluate the performance of the L. nigrescens kelp fishery, based on data from 2000, 2014, and 2018. These emergy assessments show that over this period, the empower base (R) supporting intertidal kelp beds decreased 41%, the annual emergy used in the fishing effort (F) increased by an order of magnitude, and the total emergy used in the fishing system (Y) decreased by 39%. The values of the Landings/Fishing Effort Ratio (EYR) showed a general tendency to decrease, as the Emergy Investment Ratio (EIR) increased. The economic exchange of emergy indicates that in 2014 the extractors/collectors operating the algae fishery obtained the greatest emergy gain by trading. The analysis of the emergy indicators explained the long-term changes in the sustainability of the kelp resource and the emergy balance of the economic transactions over the last 20 years. In addition, the emergy evaluation results can be used as a complement to traditional planning methods, to design and implement system-based, resource management measures to ensure a sustainable and healthy kelp fishery.