Hellenic Centre for Marine Research (HCMR)

The Greek Demo Site in the NW Thermaikos Gulf—one of the Mediterranean’s most intensive mussel-farming zones—hosts an innovative collaboration between research institutes and the aquaculture industry to restore sediment health and transform waste into valuable resources. Located within the protected Axios–Loudias–Aliakmon Ramsar/Natura 2000 system, the area faces sustained organic enrichment, habitat degradation, and the loss of natural benthic cleaners due to overexploitation and climate-driven mass mortality events.

To address these pressures, scientists, echinoderm fishers, and the mussel-farming company Mydia O Spyros are jointly implementing the Holothuria Blue Parks pilot. Native sea cucumbers (Holothuria tubulosa, H. mammata) are deployed directly beneath mussel-farm (Mytilus galloprovincialis) lines as natural bioremediators, enhancing bioturbation, increasing oxygen availability, and converting organic waste into high-value biomass for food, nutraceutical, and cosmetic markets. The pilot combines stainless-steel seabed structures and basket systems that simulate natural conditions, with monitoring running from 2025 to 2026. A second pilot—Water Column Remediation with Microalgae—is launched in 2026. Using low-cost floating bioreactors integrated with the natural plankton community, the approach targets nutrient removal, CO₂ uptake, and biodegradation of contaminants while generating high-value microalgal biomass.

Ongoing work focuses on engineering optimization, targeted consortia selection, real-time monitoring, upscaling, and full environmental and economic assessment. Beyond sediment and water column recovery, the initiative seeks to explore circular-economy pathways: valorizing mussel shells (>95% CaCO₃) for industrial and environmentally beneficial uses, and evaluating epibionts and microbial communities.

The Greek Demo Site through the 2B-BLUE HUB aims to be one of the leading testbeds for integrating low-trophic species, circular-economy innovations, and industry–science partnerships to build a more resilient and sustainable Mediterranean Blue Economy.