The production of marine finfish and shrimp requires the use of nutritionally balanced aquafeeds. Aquafeeds have become increasingly expensive, incorporate a growing number of specialty ingredients that are promoters of growth, health, and survival, and are ultimately key to achieve a superior farming performance. However, not all feed provided is converted into biomass of the target species being cultured. A non-negligible part of aquafeed nutrients often end up being wasted, as part of the feed provided is not eaten, and fared species are not able to assimilate 100% of all ingested nutrients (with these being commonly excreted through their faeces). These nutrients are present in culture water in the form of particulate organic matter (POM), dissolved organic matter (DOM) (including dissolved organic nitrogen [DON] and phosphorus [DOP]) and dissolved inorganic nutrients (including dissolved inorganic nitrogen [DIN] = NOx-N + NH4-N and dissolved inorganic phosphorus [DIP] = PO4–P). Unless an integrated multi trophic aquaculture framework is put in place, farmers will not fully recover the nutrients they have already paid for in aquafeeds. Coastal lagoons food webs can be successfully mimicked and allow farmers to sequester ingredients available in the productive environment before these are lost through effluent water. Polychaetes (e.g., Hediste diversicolor) and gammarid amphipods (Gammarus locusta) can be successfully cultured to incorporate POM and even perform a trophic upgrade of such nutrients (e.g., by biosynthesizing de novo long-chain polyunsaturated n-3 fatty acids). Ascidians (e.g., Phallusia mammillata) can be successfully employed to incorporate DOM, while halophyte plants (e.g., Salicornia ramosissima and Atriplex portulacoides) and seaweeds (e.g., Ulva spp. And Gracilaria spp.) can be employed to incorporate DIN and DIP. The biomass of these extractive species produced under this IMTA framework can be valued in in different value-chains, for food, feed, pharma and more. Overall, farmers able to use this nature-based solution will be able to benefit from circularity and frame their production under a blue-bioeconomy paradigm.
This study was performed under project “BLUE BIOECONOMY PACT” (Project Nº. C644915664-00000026), co-funded by the Next Generation EU European Fund, under the incentive line “Agendas for Business Innovation” within Component 5—Capitalization and Business Innovation of the Portuguese Recovery and Resilience Plan (RRP), as well as project “PUFAPODS Merging blue and green food systems - Using marine gammarid amphipods supplied with plant food processing side streams to produce n-3 LC-PUFA” which is supported by FCT/MEC https://doi.org/10.54499/LA/P/0094/2020).