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 x m2/nm2 reflecting surface and represents an indicator of density of pelagic fish. An arbitrary scale has been used to illustrate different levels of concentration. The acoustic data will later be used for biomass estimates.
Over most of the East Coast Shelf only very scattered recordings were made indicating a general low level of fish density. They usually consisted of traces of small schools or single fish not far off the bottom. Identification with bottom trawl was only possible in restricted areas, and showed that over the outer parts of the shelf the recordings should be attributed to Carangids and snappers with some Spanish mackerels and barracudas. An area of higher densities was found inshore south of the Manzanilla Bank and a pelagic trawl haul indicated that this was dominated by anchovies, sardines, hairtails and demersal fish. This fish stretched southwards along the coast past Pt.Galeota and further off the South Coast. It seems to be associated with low salinity Orinoco water.
During the passage up along the Northwest Coast some fish concentrations were located inshore off the north coast of Trinidad identified as anchovies and sardines with some Carangids, barracudas and demersal fish and off the northwest coast of Tobago where anchovies were caught with some Spanish mackerel and barracudas.
