Report on a Collection of Chaetognaths from Banco Chinchorro, Mexican Caribbean Sea

The most abundant species in the study area were: Sagitta enflata (74.7%), S. hispida (7.8%), and S. serratodentata (6.5%). Nine species of planktonic chaetognaths—S. enflata, S. hispida, S. serratodentata, Krohnitta subtilis, K. pacifica, Pterosagitta draco, S. hexaptera, S. tenuis, and S. bipunctata—were identified in plankton samples collected from near the surface at Banco Chinchorro, Mexico during September 1999 and March 2000. Most plankton samples were collected during the night. Highest mean chaetognath density occurred in the forereef area (5352 org/1000 m³), and lowest values in the reef lagoon (541 org/1000 m³). Cluster analysis of the stations revealed two types of assemblages, one of high densities and the other with low densities. Values of the ShannonWiener diversity index were statistically greater at the reef lagoon zone (2.2 bits ind⁻¹) than in the forereef (1.3 bits ind⁻¹).