Nutrition and Environment Interactions in Aquaculture

With the expansion of aquaculture and its increasing role in the global food system, the complex interactions between fish culture systems and the environment have come under intense scrutiny. On one side, environmental factors can influence or constrain aquaculture operations and on the other, aquaculture exerts a wide range and degree of impacts on the surrounding environment. Feeds and feeding practices are a vital cog in this bidirectional relationship between aquaculture systems and the aquatic environment. Particularly, the increasing use of nutrient-dense pelleted feed in modern intensive aquaculture has led to major environmental concerns. Nutrient loading and loss are a function of the production environment, species, system design as well as feed efficiency and composition. Using nutrient mass balance methods and bioenergetic approaches, the waste output from aquaculture facilities can be estimated and predicted. Subsequently, the management and control of aquaculture waste output should begin with changes in diet formulation and feeding strategies. Pivotal advances in feed manufacturing technology have substantially decreased the production of dietary origin waste in aquaculture. Likewise, the application of digital technologies and the use of smart feeding systems are transitioning feed management from an experience-driven to a knowledge-driven process. As the focus on environmental sustainability increases, there is also a greater emphasis on the use of feed resources in a responsible and environmentally efficient manner. This includes limiting the inclusion of fish meal and fish oil sourced from overexploited wild fishes, and increasing the use of novel plant, animal, and micro-organism-based raw materials which have less ecological costs. Life cycle assessments suggest that fish feed and ingredients are critical determinants of the environmental impact of aquaculture. Conversely, the impact of environmental changes on the nutritional requirements of fish and the biological efficiency of feed compositions is less understood. Overall, the aquaculture industry should be prepared to reconfigure and respond to newer environmental concerns over time, through innovations in feed and feeding.