IMIS

The three multidisciplinary research surveys on board the R/V Vizconde de Eza (Secretaría General de Pesca Marítima) were performed in the seamounts of Ewing and Valdivia Bank (Walvis Ridge) as a collaborative work between Spain and Namibia trough the Instituto Español de Oceanografía (IEO) and the National Marine Information and Research Centre of Swakopmund (NatMIRC). Studies on biodiversity, acoustic and geophysics, hydrography, and seabird and cetacean observations were conducted. A total of 15 823 km² were surveyed with a multibeam echosounder and 1462 km of seismic profiles, using an ultra-high resolution parametric sounder. The depth ranged between 218 m at the outcrop in the South-eastern sector of Valdivia Bank and 3000 m in the southern part of our study. A total of 210 species of fish, 60 crustaceans and 32 cephalopods were recorded. Species diversity increased by depth and four assemblages by depth strata were found: shallower (200-300 m); slope (300 - 800 m); upper deep (800 - 1300 m); and deep (1300 - 2000 m).