Figure 2 shows the surface temperature over the shelf. Off San Juan del Sur there is a decrease in temperature towards the shore which may have been caused by the prevailing northeasterly "Papagayo". Otherwise there is only a variation in surface temperature of abt 1°C over the whole of the Nicaraguan shelf. The hydrographic profiles off San Juan del Sur and Golfo de Fonseca are shown in Figure 3. There is a transition layer between about 30 and 100 m of depth with a temperature drop of abt. 10°C and a drop in oxygen content to about 1 ml/l. The parts of the shelf deeper than abt. 100 m is thus covered by cool oxygen deficient bottom water. This may affect fish distribution.
The sea surface temperature off El Salvador (Figure 2) shows a slightly increasing trend towards the shore and northwards. The hydrographic profile off Acajutla is shown in Figure 3.
In the offshore part the transition layer With a temperature drop of abt 10°C is located between 30 and 50 m of depth. Over the shelf the transition layer is less sharp extending down to about 100m.
