The Gulf of Cariaco is a subrectangular body of water, 62.5 km long (E-W) and 8.95 km of average width (N-S). It is situated in a semiarid zone in the eastern part of Venezuela, and with its enclosed body of water, is referred to here as the "Cumana Shelf".
Beathymetry showed that the submarine topography is structurally controlled, especially through the coast, where the Cariaco fault to the north, and the El Pilar fault zone to the south, are located. The absence of the shel in the mouth of the gulf is basically dur to the submarine canyon of the Manzanares river.