MapGES 2020 Cruise Report: Exploration of Azores deep-sea habitats, summer 2020

Main objective: to explore deep-sea areas of the Azores for which there is currently little or no information available on the composition and diversity of its benthic fauna in order to better understand the distribution of Vulnerable Marine Ecosystems (VMEs) and commercial fish species in this region.

Methodology: The main device used during this cruise corresponds to the Azor drift-cam, the low-cost drifting camera system designed and developed at IMAR which allows the recording of high-quality underwater video images down to 1000 m depth. The system was deployed both from a fishing vessel and from the research vessel N/I Arquipélago, from the University of the Azores.

Chief scientist: Telmo Morato

Scientific team: Telmo Morato, Carlos Dominguez-Carrió, Sérgio Gomes, Gerald H. Taranto, Manuela Ramos, Laurence Fauconnet, Luis Rodrigues, Marina Carreiro-Silva

Cruise summary: The MapGES_2020 survey was divided in 3 different legs, which were planned to explored different areas of the Azores archipelago around the central group of islands (Table 1, Figure 1). Overall, almost 100 dives were accomplished in 8 different underwater features, which includes 6 shallow seamounts and 2 island slopes.

• Leg 1, 22 to 31 August 2020. This leg aimed to survey the slopes and small seamounts around the island of Garciosa, with one day also allocated to survey Ilha Azul seamount, an area later completed in Leg 2. The importance of Leg 1 went beyond the amount of new areas explored, but corresponded to the first time that the whole Azor drift-cam system was moved between islands using a regular ferry line and also the first full survey on board of a local fishing vessel not based in Faial island. During Leg 1, 32 dives on the slopes of Graciosa and 4 dives in Ilha Azul seamount were successfully completed (Figure 1), covering more than 17 km of seabed.
• Leg 2, 24 September to 1 October 2020. This leg also aimed to survey deep-sea areas on the northern side of the central group. After 7 days of work on board of the research vessel N/I Arquipélago, 5 different seamounts were explored, as well as the slopes on the western side of Terceira island, popularly named Serreta (Figure 1). During Leg 2, 37 dives were accomplished, covering more than 20 linear km of seabed.
• Leg 3, 20 to 26 November 2020. This leg planned to explore two underwater features south of Faial and Pico islands, for which some previous knowledge was available, especially in its deeper areas. During Leg 3, 26 dives were accomplished, 13 in Condor de Fora and 13 in Baixo de São Mateus seamounts (Figure 1), adding an extra 13.3 km of seabed surveyed.

Main achievements:

1. Accomplishment of almost 100 new underwater video transects between 100 and 800 m depth, most of them in areas of the Azores that had never been explored before and for which no information regarding the composition of its benthic communities was available.
2. Discovery of diverse coral gardens and sponge grounds whose presence was unknown to science and that may fit the FAO criteria to be considered Vulnerable Marine Ecosystems (VMEs).
3. Successfully perform a 10-day survey with the Azor drift-cam on board of a local fishing vessel not based in Faial island, with dives to almost 800 m depth. This achievement demonstrates the great capacity of this tool, fully designed and developed at IMAR, to (a) rapidly assess the diversity of deep-sea benthic communities from small local vessels and (b) be moved between areas with ease.