Benthic habitat diversity in coarse sediment under high macrotidal environment

EUNIS (European Nature Information System) is the habitat typology of reference in Europe but it must be implemented by new observations, particularly for the more detailed levels of the classification in coarse sediments which were historically less explored because of sampling difficulties. Two surveys in 2010 and 2011 permitted to sample twelve rectangular areas in the mid part of the Channel dominated by coarse sediment habitats in a high hydrodynamic environment strongly influenced by tidal currents (see Trentesaux et al., this conference for the map). During the survey, four longitudinal side-scan sonar (SSS) profiles were realised (~10 nm length) in each area allowing a real time selection of sampling areas. A minimum of four 0.25 m² Hamon grab sampling stations for quantitative macrofaunal and sediment analysis and two video footages (ROV Seabotix LBV200) were selected in each area (see figure). The main objectives of this study were to re-assess the EUNIS typology along an east-west gradient in the English Channel, and to find a way to integrate acoustic information in the description and mapping of the habitats which is not yet taken into account