Abstract
The objective of the IMTA-Effect project, sup¬ported by EU ERANET-COFASP, was to provide new knowledge to sustain development of IMTA using experimental and modeling approaches. Seawater ponds (fish + filter feeders + depo¬sit feeders or macroalgae) were studied by IPMA in Portugal and HCMR in Greece. Rice-fi¬sh culture was studied by ISEM in Madagascar, and freshwater ponds in semi-separate systems for carp polyculture were studied by UDJG and Romfish in Romania, and for Azolla-Gourami in Indonesia. A compartmented IMTA that added planted lagoons to fish polyculture in freshwa¬ter ponds was studied by INRAE in France. Fi¬nally, RAS were studied by separating each spe¬cies into specific tanks by AUA in Greece and by ISEM (fish and macroalgae) and Ifremer (marine fish, phytoplankton, oysters, and ragworms) in France. The case studies showed that IMTA’s adapted management of interactions among species of different trophic groups improved the aqua¬culture system. Compared to a reference fish monoculture, the overall productivity of the sys¬tems can increase due to the production of other products or services. The efficiency of delivering feed to fish increases overall by recycling in the system loop, which decreases the environmental impacts. IMTA also diversifies aquatic products, which can increase the robustness of aquatic farms. We demonstrated the key role of prima¬ry producers (plants, micro- and macroalgae) as the engine of nutrient recycling. One advance of the IMTA-Effect project was made in system modeling. We characterized the energy distribu¬tion (DEB) of ragworms and modeled the food web structure in pond systems using Ecopath with Ecosim, combined with the use of C and N isotopes, which trace the fate of nutrients in the food web. The IMTA-Effect project was an op¬portunity to strengthen the knowledge and dif¬fusion of new practices in the aquaculture sector, thus opening new perspectives for development.