Based on analyses of the echo diagrams the type of bottom along the course tracks was classified as follows: 1: smooth even bottom; 2: more uneven but probably still trawlable bottom; 3: rough not trawlable bottom, and 4: very steep bottom. Figure 5 shows these observations for the whole shelf. The bathymetric features of the nautical charts are inaccurate in many areas. Thus the shallow bank area off the shelf in the south east part of the Tehuantepec Gulf at abt LN 14° 25', LW 93° 10' could not be located and probably does not exist.
