Preliminary report of the multidisciplinary research cruise on the Walvis Ridge seamounts (Atlantic Southeast-SEAFO)

Abstract

A total of 10285 Km2 (2780 Nm2) were covered using the multibeam echosounder, 1381 km2 from the Ewing seamount and 8904 km2 corresponding the Valdivia Bank. The area of study was divided in the following zones: Ewing, Valdivia North, Valdivia Central, Valdivia West and Valdivia South, which correspond to the principal submarine mounts that have been cartographied. A total of 50 CTD stations were taken recording conductivity, temperature, pressure, oxygen and fluorescence data, with an initial sampling protocol consisting of two perpendicular radial over each main target seamount, in a 2’x 2’ grid. At the end of the survey, in places not initially foreseen, the hydrographic stations were placed at trawl locations. The fauna and sediment samples were obtained by carrying out a-30-minute trawl using a LOFOTEN bottom trawl net. A total of 24 trawls were carried out from which; one was null (doors snagging); another only took 18 minutes of trawling at the top of a seamount.