Aquaculture Sustainability Assessed by Emergy Synthesis: The Importance of Water Accounting

Abstract

Aquaculture is one of the protein production activities with the most significant potential for global development. It is one of the fastest growing in recent years, mainly because of its efficiency in transforming feed into meat. However, the increase in aquaculture production raises some concerns, especially regarding the proper use of natural resources such as water, which is fundamental in aquaculture production systems. On the other hand, numerous systems, models, and production techniques have been developed and used to manage resources and reduce the negative impacts of the activity. However, it is not known which production systems and management practices are more sustainable, although the development and application of these technologies are crucial and profoundly influence this aspect of production. Emergy is a method that considers the contribution of nature and economy in the creation of the product and service, excluding the strictly monetary character present in conventional economic evaluations, being a model used to measure the level of sustainability in productive systems. In this sense, this study characterized the use of emergy analysis in aquaculture systems and discussed the main applications and potential uses, in addition to identifying the importance of water in the production and better destination of this resource for the economic and sustainable development of aquaculture. The systematic review methodology identified 17 articles using emergy analysis to assess environmental, economic, and social sustainability. The production systems evaluated vary between monocultures and polycultures at different production levels (intensive, semi-intensive, extensive). When all these particularities are transformed into the same unit (emjoule or solar joule), it is possible to compare different scenarios. As a primary resource of nature, water deserves more attention in the emergy accounting of aquaculture systems. It was shown the importance of a more detailed water analysis considering its effective use, impact (alteration or variation in its quality), and flow for a correct emergy analysis as a tool to promote the maintenance of the aquaculture activity over the years, which has in the water its most significant wealth.