ECOCEAN, OW, EFGL, Centre de Recherche sur les Écosystèmes Marins (CREM – UPVD/CNRS)
TRL:
8
Funding:
ECOCEAN, OW, EFGL, Agence de l'eau RMC
Knowledge sharing
The biodiversity data collected during the monitoring activities has been shared with scientists, different stakeholders and the general public via various public events — such as the OCEaN side event: Beyond Turbines: Powering the future and booting marine nature. Information about the project is also available on Ecocean’s website alongside a brochure with the most important findings is available online.
To understand the potential of nature-inclusive designs (NIDs) for floating structures to enhance biodiversity in Mediterranean Sea, with a particular focus on crustaceans, molluscs, and juvenile and adult fish populations in the open sea and coastal areas.
Short description
The Biodiversity Observation Buoy (BoB) was a floating structure located in the French part of the Mediterranean Sea (approximately 16.5 km from the coast) between 2019 and 2023. This buoy was part of the Connexstere project, which aimed to support marine biodiversity and ecological recovery through the deployment of artificial structures. BoB was equipped with 16 Biohuts®, which are boxes filled with natural substrates (oyster shells, rocks, and/or coconut fibres) and covered with mesh. Environmental monitoring took place regularly from the beginning of the project until its decommissioning in June 2023. Underwater footage and bioacoustics were used for data collection. These monitoring actions were carried out by experts from the Center for Marine Ecosystem Research at the University of Perpignan and the Ecocean team, with the support of Ifremer and France Energies Marines.
During its life at sea, BoB delivered impressive results which directly contributed to the development of NIDs for future floating structures. For example, the integration of Biohuts® at the floating offshore wind project (EFGL) installed in the Golfe of Lion by Ocean Winds in the summer 2025.
The key findings were:
1. Invasive species: No invasive species were detected on the structure.
2. Biodiversity increase: A significant biodiversity increase was observed in and around BoB in comparison to traditional buoys without Biohuts®. Five different coastal fish species (post-larvae) settled in the floating artificial habitat. The results showed that the level of fish populations was similar to the numbers observed in other coastal habitats where Biohuts® where introduced, such as around artificial reefs and ports.
3. Molluscs presence: A high quantity of molluscs was observed inside the Biohuts®. Large numbers of black scallops and a few king scallops were found. Additionally, a high density of sea urchins was detected, with approximately 20 times more urchins found where Biohuts® were introduced compared to the surrounding natural coastal environments.
4. Connectivity and ecosystem development: With appropriate collection and analysis of data, the pilot project revealed the development of biodiversity connectivity between the coast and the location of the buoy (16.5 km offshore). The bioacoustics monitoring programme lasted 18-month and showed increased fish vocalisations, with activity mainly occurring at night, similar to coastal areas. The number of species attracted to BoB exceeded expectations, confirming the potential of NID solutions in floating structures for nature enhancement and the development of ecosystems. However, the small size of BoB limited the presence of small fish, such as Sparidae, which is expected to differ in larger projects such as floating wind farms.
© Ecocean
© Ecocean
© Ecocean
© Ecocean
© Ecocean
