Maricoltura Mar Grande is proving that aquaculture can be both productive and environmentally responsible

Taranto, Italy, 20 January 2025 |

Cultivo Multitrófico Maricoltura Mar Grande

In the shimmering waters of the Ionian Sea, just 600 metres off the coast of Taranto, a fish farm is reshaping the future of aquaculture. Maricoltura Mar Grande, renowned for producing of 100 tonnes of European seabass (Dicentrarchus labrax) and seabream (Sparus aurata) annually, is leading a pioneer and revolutionary shift towards sustainable marine farming through Integrated Multi-Trophic Aquaculture (IMTA).

The facility consists of 15 floating cages, each measuring 22 metres in diameter and with depths ranging from 7 to 12 metres. The farm operates in one of Italy’s most significant coastal marine ecosystems, nestled along the Apulian coast, an area characterised by its biodiversity and economic reliance on marine resources.

This innovative system integrates traditional fish farming with bioremediators—organisms such as sponges, mussels, macroalgae, and polychaetes—that act as natural cleaners. By absorbing organic waste and recycling nutrients, these organisms prevent eutrophication, a damaging process caused by nutrient overload that triggers algal blooms and deteriorates water quality.

The initiative, part of the EU-funded REMEDIA Life project, is the result of a collaboration between researchers from several Italian institutions. Over a four-year study (2018–2021), scientists monitored two distinct zones within the facility: one implementing the IMTA system and the other employing conventional monoculture practices.

Seasonal sampling was conducted during summer and winter across all years, with additional data collected in the summer of 2021 to deepen the analysis of IMTA outcomes.

The findings were remarkable. Organic matter in the sediment under the IMTA zone was 20% lower than in the monoculture area. Species richness rose significantly, increasing from 83 taxa in 2018 to 104 taxa in 2021, with notable growth in sponges, mussels, and macroalgae. Opportunistic species like capitellid worm (Capitella capitate)—a species that thrives in polluted environments—declined substantially in the IMTA zone, highlighting the system’s ability to enhance environmental health.

The IMTA system acts as an underwater garden, with filter feeders such as mussels (Mytilus galloprovincialis) and sponges (Sarcotragus spinosulus, Aplysina aerophoba) removing particulates from the water. Meanwhile, macroalgae (Chaetomorpha linum, Gracilaria bursa-pastoris) absorb dissolved nutrients like nitrogen and phosphorus. Together, these species create a thriving marine ecosystem that boosts biodiversity and minimises the environmental footprint of fish farming.

The system also introduced greater trophic complexity into the ecosystem. Filter-feeding species increased from 23 taxa in 2018 to 65 taxa in 2021, while previously absent predators and omnivores became prominent, reflecting a more balanced and interconnected food web.

Beyond ecological gains, the IMTA system offers significant commercial benefits. High-value by-products like sponges, with applications in medicine and biotechnology, and macroalgae, widely used in cosmetics and pharmaceuticals, have enabled the farm to diversify its revenue streams.

Furthermore, the enhanced biodiversity has opened new opportunities for underwater tourism, with the visually rich marine habitat attracting eco-tourists and divers—a unique blend of sustainability and economic innovation.

As the Mediterranean grapples with the challenges of climate change and growing demands for sustainable food production, Maricoltura Mar Grande presents a replicable model for balancing productivity with marine conservation.

For now, the waters of Mar Grande serve as a beacon of hope, showcasing how science and innovation can shape a more sustainable future. Whether this approach will ripple across the industry remains uncertain, but the tide of change is already here.

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