Cap Sicié : Artificial reefs to revive the marine environment

The Remora* project aims to help marine biodiversity re-establish itself in areas where it had disappeared due to pollution. A pilot ecological recovery operation that is proving extremely promising.
The essential
Successfully bring about the ecological recovery of formerly polluted areas.
Bring back flora and fauna in areas where life had disappeared following pollution.
Veolia's response
Immerse artificial reefs so that they serve as a habitat, larder and growth area for young fish.
Published in the dossier of November 2017

Ecological recovery

The Remora project consisted in immersing two identical 360-m3 artificial reefs at a depth of 15 meters off the coast of Toulon in April 2015. Each composed of 18 modules of various shapes such as hedges, tepees and rollers, they were deliberately arranged in order to be able to assess the technical and operational feasibility of a restoration action. The first was placed under the influence of the 60,000 m3 of treated wastewater – rich in organic matter and therefore in nutrients for fauna – discharged every day by the Amphitria sanitation plant; the second, sheltered from the currents, is located at Cap Vieux. The aim is to compare the action of each reef on the return and development of fauna and flora. To date, Remora has entered the five-year active scientific monitoring phase.
Since spring 2016, the first scientific observations have been encouraging: the habitat is improving. The different modules seem to be playing their role of attracting a host of fish, crustaceans, and echinoderms – starfish, sea urchins, sea cucumbers, etc. Above all, pioneering species of seaweed such as coralligenous algae, which can exceed 10 centimeters in certain places, are beginning to colonize along the synthetic fibers. The program is also expanding its assessment mission to include these two reefs’ surroundings, especially the neighboring Posidonia meadow, an invaluable ecosystem particularly for its ability to sequester and store carbon in underwater sediments.
This collaborative project, led by the Pôle Mer-Méditerranée hub and co-funded by the Rhone-Mediterranean and Corsica Water Agency and the Veolia foundation, also relies on the skills of water treatment and ocean environment professionals: the artificial reef designer DBS, the engineering company specializing in marine environments ERAMM, the Paul Ricard Oceanography Institute (IOPR), a local marine survey company (IXSurvey), and Veolia, which runs the Amphitria plant.

Sometimes nature needs a helping hand. Especially when it has been damaged due to humanity’s actions in the past. Helping biodiversity reassert itself is the aim of the Remora project launched in 2011 by several partners including the Veolia foundation, the Rhone-Mediterranean and Corsica Water Agency and the Paul Ricard Oceanography Institute (IOPR). The initial results are extremely encouraging. Since the 1990s, the quality of coastal waters has made huge progress. At the time, the city’s wastewater was discharged directly into the sea with heavy environmental consequences. The introduction of a wastewater system has made it possible to considerably limit this pollution and restore highly satisfactory water quality. However, as the marine environment had been destroyed, seaweed, fish and crustaceans had disappeared. Hence the idea of recreating a habitat conducive to the reappearance of biodiversity.

Artificial reefs

The experiment was conducted at Cap Sicié in Toulon harbor (Var department, France). This area enjoys very good quality water thanks to the Amphitria wastewater treatment plant operated by Veolia. In April 2015, two artificial reefs were installed at a depth of 15 meters, one near the discharge point for the treated water, the other slightly further away to be able to compare developments. These lightweight structures, which are relatively inexpensive to immerse, are formed of fiberglass and epoxy resin rods attached to concrete blocks. These reefs serve as a habitat, larder and even a nursery for the different species that find refuge there.
Two years later, results have exceeded expectations. “We are pleasantly surprised by the reaction of the marine environment. We find lifecycles and certain animals – squid, cuttlefish, crustaceans and fish – are reproducing in these reefs,” observes Pierre Boissery, an expert on the Mediterranean Sea and Coast at the Rhone-Mediterranean and Corsica Water Agency. “This is confirmation that water quality is no longer hindering a return to biodiversity.”

Deux ans plus tard, les résultats dépassent les attentes.

« Nous sommes agréablement surpris par la réaction du milieu marin. On retrouve des cycles de vie et certains animaux – calamars, seiches, crustacés et poissons – se reproduisent dans ces récifs, observe Pierre Boissery, en charge de l’expertise pour la mer et le littoral méditerranéen au sein de l’Agence de l’eau Rhône-Méditerranée-Corse. Cela confirme que la qualité de l’eau n’est plus un frein au retour de la biodiversité. »

Four-phase restoration


The Remora project falls firmly within the Paul Ricard Oceanography Institute’s longstanding mission: knowledge and protection of the ocean. The IOPR originally fought to improve water quality. “Forty years ago, there was no wastewater treatment plant and raw water was discharged directly into the sea,” recalls Patricia Ricard, its president. Once this battle was won, it was logical for the IOPR to tackle the question of restoring biodiversity via the Remora project. “We have contributed our skills in terms of biology, our knowledge of nature and the depth of marine habitats. For its part, the Veolia foundation initiated the project and helped fund it with the Rhone-Mediterranean and Corsica Water Agency. It’s great interdisciplinary work combining skills in microbiology, marine biology, engineering and chemistry.” The results can be seen by all. In Port- Cros, for example, there were only four groupers left in 1963. Today there are over 700.
“Environmental pollution is therefore not irrevocable, restoration is possible!” enthuses Patricia Ricard.

The experiment can therefore be reproduced, as long as the four phases necessary for successful restoration are followed: first of all, set aside remarkable spaces where biodiversity is preserved; then improve sanitation to restore the quality of the water discharged into the sea; next, set up integrated management, in which everyone works together to limit the impacts on the marine environment: hotels, technical services, yachtsmen, farmers, etc. It is only at this point that the ecological ocean environment restoration can begin. “The sea is a good girl: it is resilient if we avoid pollutants,” highlights Patricia Ricard, President of the IOPR (see boxed text).

The Remora project is already a success and it’s only the beginning! Veolia has just won a call for tenders for a large-scale ecological restoration project near Cassis in the Bouches-du- Rhône department.

“The technologies will be different, but the rationale remains the same: recreating a habitat to encourage the repopulation of previously polluted areas,” states Emmanuel Plessis, Veolia’s Development Director in Provence. “We are moving from an R&D phase to its reproduction on a wider scale, involving the fishermen concerned.”

More generally, the Group is going to provide a worldwide service supplementing its wastewater projects with an ecological restoration offering.

“In Europe, the law of August 8, 2016 on biodiversity recovery holds great potential for us,” concludes Emmanuel Plessis.


5 years’ immersion of two artificial reefs
2 campaigns/year: at the end of winter for the materials’ resistance and hold; in the spring and fall for monitoring the fixed biomass and fish.
1st results from the 2015 and 2016 campaigns:

  • water quality is no longer a factor limiting the restoration of ecological functions;
  • in a sandy environment where the Posidonia meadow had disappeared, renewed growth of fauna and flora specific to attached species in shallow coastal waters on the artificial reefs.


Find out more:
> www.institut-paul-ricard. org/Reconquete-d-un-milieu-degrade
> Pole-Mer-Mediterranee/Actualites/News/ Essai-pilote-de-restauration-ecologiqueen- milieu-marin-cotier-degrade-tel-est-lobjectif- du-projet-Remora