Figure 4 illustrates the distribution of all fish as observed with the acoustic integration system. This will mainly show the pelagic species, but some demersal fish which lifts off the bottom, especially at night, will also be included. The units of acoustic reflection is 0.1 × m2/nm2 reflecting surface. This unit is not directely proportional to fish density, since small sized fish gives a higher acoustic reflection per unit weight than bigger fish, but in gross terms the figures give a fair picture of the main distributional features of the pelagic fish in the area. An arbitrary scale has been used to illustrate different levels of concentration. The acoustic data will later be used for biomass estimates.
The acoustic registrations around the Guajira Peninsula were predominatly made from anchovies (Engraulis eurystole), sardinella (S. aurita), threadfin herring (Opisthonema oglinum), and mackerels (Scomber japonicus, Sarda sarda). The resources were not substantial, and formed more occasional patches than uniform aggregations of greater extent. Further west the acoustic registrations were scarce, with only three small patches exceeding a very scattered general picture.
