Multiscale variability of the Chaetognatha along a Caribbean reef lagoon system

We studied the distributional patterns of the chaetognath community along a large reef system of the western Caribbean during 3 seasons using a multiscale hierarchical sampling design. Hydrographical and biological parameters were measured at 3 different reef lagoons (100 km scale) and in a field of 10 km at each lagoon. Biological data were analyzed using a nested multivariate analysis of variance, and hydrographical data were analyzed with T-S graphics. Results showed seasonal differences of both hydrographical and biological data. Spatially, the chaetognath composition appeared to be relatively homogeneous over the 100 km scale at least during dry and rainy seasons, when neritic forms are widely dominant; however, during the season of northerlies a shift in the chaetognath composition occurred, with oceanic forms becoming dominant. Hydrographical conditions and chaetognath composition were variable within lagoons. It is inferred that the observed seasonal patterns of the reef chaetognath community at the 100 km scale is affected by: (1) the largescale physical processes including the seasonal strength of the Yucatan Current and the variation of the sea level within the lagoons and (2) the local geomorphology of the reef lagoon, including the structure and height of the reef crest. The differential effect of these factors in the 3 reef lagoon systems determines the extent of the oceanic influence and structural profile of the chaetognath community. Multiscale studies on other taxa and a quantitative evaluation of predation in the community should be developed in order to provide significant insights into the processes involved in the dynamics of the reef zooplankton. Understanding the local variability patterns will help in developing effective management and protection actions for the reef ecosystem.