These artificial reefs are located 200 m from the mouth of the city of Marseille's wastewater discharge at Cortiou. Sandrine Ruitton and Delphine Thibault of the EMBIO team dived there on Thursday 28/10/21 and observed a pile of macro-waste at the foot of the reefs, probably as a result of last week's heavy rain. In addition to this waste, the surface of the sediment was covered with a whitish film due to bacterial decomposition. The MIO has been carrying out seasonal monitoring of the ichthyofauna and benthic invertebrates on these artificial reefs for the past 4 years.