The DEMETRA 25 cruise on board of the R/V Gaia Blu was carried out on 21^st September – 2^nd October in the Gulf of Naples (Mediterranean Sea) over the three areas explored and selected during the ECOREST II: Dohrn Canyon, Magnaghi Canyon and the adjacent Cuma Channel. Different members of the REDRESS consortium were on board: UNIVPM, CNR and SZN. Scientists of UNIVPM monitored the 3D printed eco-reefs and the Artificial Structures for Deep-Sea recruitment and Ecosystem Restoration (ASDERs) through ROV surveys, also collecting data on the first year of recruitment by retrieving one Artificial Reef Monitoring Structure (ARMS) per structure. ROV operations were fundamental also for the recovery of the sensors (micro-CTD, hydrophones and current meters) and the HD cameras, from which UNIVPM and SZN scientists retrieved the collected environmental data, soundscape recordings and videos. All these instruments were then maintained and re-deployed. Sampling of seawater (Niskin bottles) and sediment cores (box-corer and multi-corer) were carried out to better characterize the biochemistry and diversity (through eDNA analyses) of both the water column and the sediment of the canyons’ areas. ROV explorations were coordinated by the CNR navigation scientists to progress with the mapping of target cold water coral habitats of the Dohrn Canyon, leading to the discovery of a huge extended reef of mainly Desmphyllum pertusum and Madrepora oculata at ca. 500 m depth.