Population Distribution of Tripneustes ventricosus in a Coral Reef Lagoon

Authors: Salvatore Caldarello & Katarina Norte

The West Indian Sea Egg, Tripneustes ventricosus, finds habitat in coral reef lagoons at an unequal distribution. Population density and size distribution trends were observed in the natural setting. Three hypotheses were formed upon these observations: population density increased as we approached the reef crest, population density was selective for substrate, and average urchin size increased as we approached the reef crest. Data was collected by 25 meter transect lines in parallel approaching the reef crest. All the Tripneustes ventricosus that lay along the transect lines were recorded on what substrate they reside on and a random subset of Tripneustes ventricosus along each transect were measured. Patterns were interpreted from the data collected including: increasing population density near the algal crest, a preference for coral substrate over grass and grass over sand, and increasing size of Tripneustes ventricosus upon approach of the reef crest.

Finding Tripneustes ventricosus along the transect line