Transforming sustainable aquaculture by applying circularity principles

Abstract

A circular economy is considered one way to reduce environmental impacts of human activities, by more efficient use of resources and recovery, resulting in less waste and emissions compared to linear take‐make‐dispose systems. Muscat et al. developed five ecological principles to guide biomass use towards a circular economy. A few studies have demonstrated environmental benefits of applying these principles to land‐based food systems, but to date, these principles have not been explored in aquaculture. The current study expands on these principles and provides a narrative review to (i) translate them to aquaculture, while identifying implications for the main species and production systems, and (ii) identify the main pathways to make aquaculture more circular. We show that the underlying concepts of the ‘safeguard’, ‘entropy’, and ‘recycle’ principles have been well researched and sometimes well implemented. In contrast, the ‘avoid’ and ‘prioritise’ principles have been explored much less; doing so would provide an opportunity to decrease environmental impacts of aquaculture at the food‐system level. One example is prioritising the production of species that contribute to food and nutrition security, have low environmental impacts and thinking at wider food system scale to avoid feed‐food competition in aquaculture. We identified six priorities that could make aquaculture more circular: (i) increase production and demand for the most essential species, (ii) decrease food loss and waste at farm and post‐harvest stages, (iii) support nutrient recycling practices at multiple scales, (iv) adapt aquafeed formulations, (v) inform consumers about benefits of species of low trophic levels and other environmentally friendly aquatic foods, and (vi) address urgent research gaps.

Circularity Assessment in Aquaculture: The Case of Integrated Multi-Trophic Aquaculture (IMTA) Systems

“…As part of the present study, nutrient management and the use of resources were identified as the two principal attributes through which IMTA systems contribute most to circularity. In line with Chary et al [10], nutrients and resource use are fundamental pillars embedded in the principles applicable to aquaculture (safeguard and regenerate, avoid, prioritize, reuse and recycle, and entropy). In this sense, a set of metrics was defined for the evaluation of nutrient recycling and resource use efficiency, with the aim of providing a comparison of circularity performance between the monoculture and IMTA scenario for each laboratory.…”

“…This means that the system can better deal with the frequent electricity outages if the recirculation rate is high, as less water needs to be heated to 25 • C. The Brazilian IMTA lab is an intensified system that is comparatively worse than pond systems in terms of energy consumption. The energy indicator reflects the entropy principle recognized by Chary et al [10]. However, this study does not consider energy sources, as they would not necessarily reflect the performance of multi-trophic production.…”

“…In addition to the definition, the range of examples is also very extensive for aquaculture, and no previous studies are available that provide the state of the art of the real and current implementation of the circular economy in the sector [10]. The concept of circular aquaculture can be addressed in many ways [11], but generally, circularity in aquaculture includes the adoption of practices regarding waste management [12][13][14], the recycling of nutrients [15][16][17][18], or the incorporation of novel ingredients in feeds derived from the bio-economy [19,20].…”

Development and application of low-cost and environment-friendly techniques for fish sperm cryopreservation

“…One of them is the use of the circular economy, which aims to prevent resource depletion, close energy and materials loop uses, and facilitate sustainable development (Prieto-Sandoval et al, 2018). This entails optimizing resource utilization to enhance efficiency and minimize waste generation and emissions by aquaculture (Chary et al, 2023). This ambitious effort requires innovating and advancing sustainable techniques within the industry (FAO, 2022).…”