Ecosystem-based approach to aquaculture (EAA) strategies require understanding of the relationship between aquafeeds and aquaculture species to maximise consumer growth performance, quantify elemental flow of nutrients, and minimise waste output. A new bridging framework, Geometric stoichiometry (GS) unifies the disciplines Nutritional geometry (NG) and ecological stoichiometry (ES) by extending the equations of ES to include core NG concepts by using macromolecules as currencies and dietary regulation to balance nutrient deficits and excesses by the consumer. We explore the feasibility of using this approach to investigate how different formulated feed ingredients affect consumer intake to maintain C:N homeostasis, growth and waste output using opportunistically available test cases for slipper lobster (T.australiensis) and Atlantic salmon (Salmo salar).
Model outputs indicate that different crude protein sources (aquafeed ingredients) and dietary inclusion levels contribute to the most variation in consumer intake and growth performance. Based on a selected number of ingredients, the model predicted highest nitrogenous waste output for soybean meal and lowest for krill meal despite soybean meal containing lower levels of crude protein. We highlight next steps for refining the GS model for use in aquaculture applications, including targeted nutrition experiments to obtain feed and species-specific parameters and integration into ecosystem models.