Spatial variation of Snapper and Grouper larvae in Yucatan Shelf

Abstract

The objective was to analyze the abundance and distribution of snappers and groupers in the Yucatan shelf. We analyzed forty-five samples of ichthyoplankton that were taken from oceanographic research (Yucatan03-A) during September 2003. Superficial tows were made with a Bongo net. A total of 3,963 organisms were collected, they belong to 50 fish families. Three families (Carangidae, Gobiidae y Clupeidae) represented more than 50% of the density. Lutjanidae and Serranidae families were within the nine most abundant families, with a total density of 713.8 ±60 org./100 m3 . Serranidae family is represented by species of the genus Anthias, Diplectrum, Epinephelus, Liopropoma, Serranus and Epinephelus fulvus, whereas Lutjanidae is represented by Lutjanus analis, L. campechanus, L. griseus and L. synagris. The highest density species was L. synagris, representing 28.9% of material reviewed, followed by E. fulvus, L. analis and L. campechanus. The analysis of the cluster of stations allowed identifying three oceanographic zones at a horizontal level: West, Center and Upwelling (in the East). The groupers larvae were distributed mainly in the Center whereas snappers larvae were distributed in the East of the shelf, this suggests that the spawning of these families occurred in different parts of the shelf, avoiding in this way the competition for food in their first larval stages. The current of Yucatan promotes an Ekman transportation that produces an upwelling that generates an increment of phytoplankton, zooplankton and ichthyoplakton that favors the fish recruitment, a fast growth and a diminution of their larval stage.