Integrated multi-trophic aquaculture systems: energy transfers and food web organization in coastal earthen ponds

• Published in: Aquaculture Environment Interactions
• Main Authors: Gamito, Sofia, Quental-Ferreira, Hugo, Parejo, Aida, Aubin, Joël, Christensen, Villy, Cunha, Maria Emilia
• Other Authors: Centre of Marine Sciences Faro (CCMAR), University of Algarve Portugal, Faculdade de Ciências e Tecnologia Faro (FCT), Universidade do Algarve (UAlg), Instituto Português de Investigação do Mar e da Atmosfera (IPMA), Sol Agro et hydrosystème Spatialisation (SAS), Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut Agro Rennes Angers, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Institute for the Oceans and Fisheries, University of British Columbia (UBC)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2020
• Subjects: Integrated multi-trophic aquaculture systems; IMTA; Earthen pond ecosystems; Ecosystem energy transfer; Ecopath models; Sustainable aquaculture; [SDV]Life Sciences [q-bio]; Imta; Crassostrea gigas
• Online Access: https://hal.inrae.fr/hal-04576737; https://doi.org/10.3354/aei00375

International audience Three Ecopath models were built to reproduce 3 experimental treatments carried out in earthen ponds located in Olhão, southern Portugal, to understand the energy transferred and the ecosystem state in integrated multi-trophic aquaculture (IMTA). These earthen ponds behave as simplified ecosystems or mesocosms, with well-defined borders, where the relationships between trophic groups can be described through ecosystem modeling. Different combinations of species were produced in these ponds, corresponding to the 3 treatments: (1) fish, oysters and macroalgae (FOM); (2) fish and oysters (FO); and (3) fish and macroalgae (FM). The managed species were meagre Argyrosomus regius , white seabream Diplodus sargus , flathead grey mullet Mugil cephalus , Japanese oyster Crassostrea gigas and sea lettuce Ulva spp. The results showed that the total amount of energy throughput was 15 to 17 times higher when compared with an equivalent naturalized system. The high biomass and low recycling indicated an immature system with low resilience and low stability that demands high rates of water renewal and aeration to maintain good water-quality levels for finfish production. The addition of oysters and macroalgae in the FOM treatment appeared to improve the water quality, since oysters controlled the excess of phytoplankton produced in the ponds by ingesting a fair amount of the phytoplankton, while the macroalgae helped in the absorption of excess nutrients and created a habitat for periphyton and associated macroinvertebrates. Some ecosystem attributes of the FOM ponds approached the values of the naturalized model, suggesting a possible path towards more sustainable aquaculture.