Diadema antillarum is a shallow-water sea-urchin from the tropical Atlantic whose populations almost disappeared in 1983-84, because of widespread mortalities, which reached 87-100%. In Venezuela, urchin population densities before the mortality event were comparable to those of other Caribbean regions; however, later abundancies remain unknown. Daytime samplings were carried out on different dates, evaluating areas that ranged between 22 and 565 square meters. For this, transects were placed with a variable length that depended on the extension of the coral or rocky community present, as well as the distribution of Diadema populations. The sea urchins were quantified using a 1 square meter quadrant as a sampling unit, which was placed along the transect, spaced according to the size of the evaluated area and the characteristics of the coral or reef community (Table 1). Diadema density was referred to as the number of urchins per square meters.