A - Objectives

The objective of this campaign is twofold: (1) Support to Public Policies for all MSFD and habitat extent measurement (descriptor 6); (2) Research for the genetic part.

The main objective is to carry out high resolution mapping of all coral populations. The currently known distribution consists of observations made from Comex's ROV Achille (Medseacan and Marum Campaigns, 2009), these observations made it possible to locate populations at the head of the canyon (Fabri et al., 2014; Fiala-Medioni et al., 2012). However, these dives did not make it possible to map the extent of the populations (reduced camera field). For this purpose a methodical and exhaustive acquisition on the various sites is necessary. This mapping is technically possible with the Ariane H-ROV.

The second objective of this campaign is to collect coral samples to analyze the connectivity between the Lacaze-Duthiers population and the one of Cassidaigne canyon, and those of the Atlantic, this in the framework of the European project H2020-ATLAS (Arnaud-Haond et al., 2017, Becheler et al., 2017a, Becheler et al., 2017b, Dubois et al., 2016).

B - Results

Results from the video analysis will produce the distribution and density maps of the two coral species, which form vulnerable ecosystems in a fragmented habitat (Davies et al., 2017). This information will complement the lack of knowledge on deep ecosystems reported by the MSFD. Results will provide data and information for the project IDEM (Implementation of the MSFD in the Deep Sea Mediterranean).

The results concerning the population genetics will feed the project ATLAS (European Project H2020: A Trans-Atlantic assessment and deep-water ecosystem-based spatial management plan for Europe 2016-2020), which although focused on the Atlantic ecosystems includes a significant part of data acquisition for the understanding of present and past connectivity links (oceanographic and biological) with the Mediterranean, and the way in which these influence the populations at the scale of the two ocean basins.

In addition, the two coral reef builders are part of the eDNAbyss project (call for major France Genomics project) and the sequencing of their genome is planned at Génoscope in this context. Sequencing genomes requires a large amount of DNA from a single individual (here a single colony without suspicion of anastomosis of fragments of different origins). Obtaining fresh tissues that can be packaged specifically for this purpose will probably be necessary at least for L. pertusa for which the samples in the collection do not have sufficient level of quality or quantity.