The Taumotou Archipelago, is considered as a potential area for the occurrence of cobalt rich ferromanganese crusts. A detailed seismic and seabeam survey carried out on the northern extension of the plateau has identified topographic highs along 2 main structural directions N 80E and N 150E. In this area, two sites have been surveyed with seabeam, 3.5 kc, and SAR side looking sonar; in addition, dredging and bottom photographs survey have been performed. For all the polymetallic crusts sampled dredged between 1,600 and 600 m, we confirm the enrichment in cobalt as a depth function; the increase in cobalt content is maximum at the outer part of the samples.