RRS Discovery DY200, 23 September – 12 October 2025. AtlantiS, PISCES, REDRESS, RISC, MARS and JNCC survey at Greater Haig Fras and The Canyons MCZs

Expedition DY200 combined at-sea activities and observations for a series of funded projects with equipment trials for the Marine Autonomous and Robotics (MARS) facility at the National Oceanography Centre in Southampton. The work was part of a wider effort to increase our understanding of deep-water benthic habitats of conservation interest, particularly of their long-term variability and their resilience to anthropogenic impacts.

For the NERC-funded National Capability programme AtlantiS (“Atlantic Climate and Environmental Strategic Science”, NE/Y005589/1), AUV and towed camera surveys were carried out at two of the programme’s long-term benthic observation sites: the Greater Haig Fras and The Canyons Marine Conservation Zones (MCZs). For the Horizon Europe-funded project REDRESS (“Restoration of Deep-sea habitats to Rebuild European Seas”; GAP No 101135492), 15 artificial reefs were deployed in The Canyons MCZ. They will be revisited in the coming years. To support this future monitoring effort, and to aid the already ongoing monitoring effort in the MCZ in general, an extensive programme of towed camera deployments was carried out for the Joint Nature Conservation Committee (JNCC).

In parallel, the expedition enabled a range of more technical operations: the recovery of two moorings deployed during DY196 in the area for the NERC-funded PISCES project (Processes drIving Submarine Canyon fluxES; NE/W005441/1), the recovery of a hydrophone lander deployed during JC278 for a NOC-internally funded project, and most importantly, extensive trials with the Autosub5 AUV, with the aim to train several new members of the team in the deployment, recovery, mission planning and execution of the Autosub5 missions. In addition, a new AUV anchoring system was tested as well.

Wherever possible, the AUV trials were planned in a way that the data obtained added value to the projects mentioned. Overall, the team completed 14 AUV missions, 29 SeaSpyder camera tows, 9 CTD casts and 8 anchor tests, as well as recovering the requested equipment successfully and deploying the 15 ecoreefs. EM710 multibeam echosounder data were also collected on the transits. The new data provide once again a new time-point in the long-term time-series of the Greater Haig Fras MCZ and The Canyons MCZ, and will enable the evaluation of long-term changes in those areas, particularly in The Canyons MCZ that was closed to bottom fishing just 3 years prior in 2022.