Fish for food or food for fish? Use of material flow analysis to optimize protein availability of seafood products for human consumption

Abstract

The growing pressure on pelagic resources and the dilemma of redirecting high-nutritional whole fish to aquafeed, stress the need for quantitative evidence to maximize marine-protein availability for human consumption. This study compares two scenarios with anchovy (Engraulis spp.) and tuna (Thunnus spp.): 1) minimally processed marine biomass for direct human consumption (DHC); and, 2) whole-fish reduced into fishmeal and fish oil (FMFO) for aquafeeds (indirect human consumption), with trout (Oncorhynchus mykiss) as the farmed species. A material flow analysis was performed using 1 t of cleaned pelagic-fish ready for DHC as functional unit, with system boundaries spanning from wild fisheries landings to fish on the plate. Mass-protein balances were modeled with STAN software. Net relative protein-return, energy-return, and the relative-profitability indicators were calculated for each product-process. Results show that all indicators applied favor DHC, even under optimized feed conversion rates. In terms of protein efficiency, these findings corroborate that DHC of pelagic fish outperforms its use as aquafeed, making it the preferred strategy, especially in contexts of food insecurity and limited supplies of high-biological value protein.