The WALTERS SHOAL oceanographic cruise is part of the project "Conservation and Sustainable Use of Underwater Mountain Ecosystems and Hydrothermal Sources in the South West Indian Ocean. Beyond Areas of National Juridiction", led by the Global Program for the Marine and Polar Environment of the IUCN (International Union for the Conservation of Nature) and supported by the French Fund for the Global Environment (FFEM). The overall objective of the project is to improve the conservation of biodiversity and underwater ecosystems and hydrothermal springs in the southwest Indian Ocean by deepening scientific knowledge, strengthening governance and improving Integrated management beyond areas under national juridiction. The target area is the Walter's Shoal discovered in 1962 by the South African ship SAS Natal. It is a huge underwater mount that rises to -15 m (some sources also say 18 m) at the southern end (33 ° S) of the Madagascar Ridge. Its area delimited above the isobath 500 meters is estimated at 400 km2. The Walters Shoal is one of the rare structures of the Indian Ocean (with the Saya de Malha bank, in the north of Mauritius) simultaneously culminating in the photic zone and being located in international waters: it is this particularity that has led to the choice of a scientific target for the project "Conservation and sustainable exploitation of the ecosystems of seamounts and hydrothermal springs in the southwest of the Indian Ocean beyond areas of national jurisdiction". The Walters Shoal Cruise is organized in two main scientific components: 1) The benthic component is focused on the inventory of the benthic fauna and flora according the methods performed by the MNHN in the context of the Tropical Deep Sea Benthos program. The sampling will occur in the depth range of 50-2000 m. The results will be compared to those obtained in the South Madagascar thanks to the ATIMO VATAE expedition (2010) performed by MNHN. The exploration of the fauna of the Walters Shoal will be essential for providing data for the conservation management of this seamount. The benthic compartment could be composed of large distribution species from either South Africa or South Madagascar and able of colonization thanks to the pelagic larval dispersion. The fauna and flora of Walters shoal should be composed by a mixture of endemic species, non-endemic species harboring either a strong genetic structuration (weak connectivity) or without genetic structuration (strong connectivity). 2) The pelagic component will investigate the signature of the physical processes resulting from interactions between currents and topography and originating the biological productivity around the Walters Shoal. It will also perform an inventory of migrating megafauna (seabirds and marine mammals) on the studied site. The environmental characteristics comprising the planktonic component (micronecton, zooplankton) will be compared to other regions on the Indian Ocean (Mozambic channel, Reunion Island) and the Mad-Ridge seamount. The related project is FFEM-SWIO "Conservation and Sustainable Use of Seamount and Hydrothermal Source Ecosystems in the Southwest Indian Ocean beyond Areas of National Jurisdiction".