Assessment of demersal fishes and icthyoplancton in the Colombian Caribbean Sea, including oceanographic conditions part III: research cruiser INPA-VECEP/UE/DEMER/9604 (april, 1996)

Abstract

To evaluate the demersal fish availability in the Colombian Caribbean Sea, we completed the third of three oceanographic cruises on april 8th –22nd 1996, in order to sample during three different oceanographic seasons: moderate upwelling (June 1995, INPA-VECEP/UE/DEMER/ 9507); no upwelling (October-november 1995, INPA-VECEP/UE/DEMER/9510); strong upwelling (april 1996, INPA-VECEP/UE/DEMER/9604). During the last cruise, we took 26 fishing haul samples, and 42 oceanographic and icthyoplankton samples in the study area (from Puerto Estrella to Islas del Rosario). The higher catch per unit effort (CPUE) values were registered in the NE zone (124.4 kg/0.5 h). The average density of the entire area was 4.74 t/mn2, for a total biomass of 12932 t. The predominant resources were snappers (Lutjanidae), whose estimated biomass was 3612 t. The most abundant commercial species were the mutton snapper (Lutjanus analis) and the lane snapper (L. synagris), followed by the porgies (Calamus spp.). The highest average values for zooplankton biomass and egg number were recorded in the NE zone while in the Central zone we encountered the highest average value of larvae. Comparing the present results with those of the previous surveys, we found an increase in the demersal fish resources, as well as increased zooplankton biomass and egg number. These findings were coupled by strong and extended upwelling in the NE area (between Punta Gallinas and Manaure), event that caused an salinity increase (36.8) and a temperature decrease (23.5°C).