Abstract:
Studies on the density and gut contents of 3 dominant sea urchin species Echinothrix diadema, Echinothrix calamaris and Diadema setosum, were conducted in a shallow-water coral reef at the Redang Island Marine Park, Terengganu. Gut contents of sea urchins were analyzed for organic and inorganic fractions. The inorganic fractions were further separated into calcium carbonate and non-soluble residual. The feeding rates of the three dominant sea urchins were compared in three different environmental components. The data obtained were used to estimate the role of sea urchins on the carbon balance in reefs and their role in food web. The total sea urchin density was 16 individuals /100m2 . Echinothrix diadema exhibited the highest density at 10 individuals /100m2 , followed by E. calamaris with densities of 4 individuals /100m2 and D. setosum at 2 individual /100m2.
