Notes on the Gracious Sea Urchin Tripneustes gratilla (Echinodermata: Echinoidea) in Pag-asa Island, Kalayaan, Palawan, Philippines

Abstract

The Gracious Sea Urchin Tripneustes gratilla is one of the most heavily exploited sea urchins in the Philippines. However, knowledge about its status in Palawan especially in Pag-asa Island, Kalayaan is wanting. The study was conducted to determine the size structure, population density and test diameter-weight relationship of T. gratilla in Pag-asa Island, Kalayaan. Transect surveys at the intertidal area of the island revealed an average density of 3,500 ind.ha-1. The test diameter ranged between 2.6 and 8.8 cm, and body weight ranged between 8 and 248 g. Other than T. gratilla, four other echinoid species were recorded but in very less number. While it appears that T. gratilla is under exploited in Pag-asa Island, policies affecting its sustainable utilization are suggested.