Abstract
Integrated Multi-Trophic Aquaculture (IMTA) is an emerging approach that promotes environmental sustainability, economic resilience, and social acceptability in aquaculture. By co-culturing species from different trophic levels—typically fed organisms such as Atlantic salmon (Salmo salar), extractive shellfish such as blue mussels (Mytilus edulis), and seaweeds—IMTA systems recycle waste nutrients into valuable biomass. Fed species release soluble inorganic nutrients (e.g., ammonia, phosphates) and organic particulates, which are subsequently utilized by seaweeds and filter-feeders, reducing eutrophication and improving water quality. This nutrient cycling not only provides environmental remediation but also enhances overall productivity and biodiversity.
Commercial-scale IMTA projects, notably in the Bay of Fundy (Canada), Norway, Scotland, and Ireland, have demonstrated the feasibility of combining salmon, mussels, and kelp in synergistic production systems. In India, initial efforts by ICAR-Central Institute of Brackishwater Aquaculture (CIBA) and ICAR-Central Marine Fisheries Research Institute (CMFRI) have explored IMTA models integrating shrimp, milkfish, pearl oysters, seaweeds (Gracilaria, Kappaphycus), and mussels in coastal waters of Tamil Nadu and Kerala. These systems highlight IMTA’s potential for nutrient recycling, livelihood diversification, and improved farm profitability under tropical conditions.
Economically, IMTA diversifies revenue streams and reduces market and environmental risks compared to monocultures. Socially, it enhances the public perception of aquaculture by addressing concerns about environmental impact. Scientifically, IMTA builds upon traditional polyculture practices but introduces modern principles of trophic integration, nutrient recovery efficiency, and ecosystem-based management.
In conclusion, IMTA represents a viable pathway for sustainable aquaculture development, balancing ecological health with commercial viability. Scaling up requires further optimization of species combinations, trophic ratios, and governance frameworks to ensure long-term sustainability.
Keywords: Integrated Multi-Trophic Aquaculture (IMTA), Atlantic salmon, blue mussels, seaweed, shrimp, India, sustainability