In Situ Observation on the Mass Aggregation of Edible Sea Urchin Stomopneustes variolaris in Shingle Island, Gulf of Mannar

Abstract

This study report significant observation on the mass aggregation of sea urchin species Stomopneustes variolaris from Shingle Island. S. variolaris is well known edible sea urchin species to coastal population. Intensive underwater surveys were conducted during the period of January and February, 2019 at different sites of Mandapam group of Islands in Gulf of Mannar. S .variolaris were found underneath and periphery of the dead reef, on the algal bed and on the exposed substratum. The density of the species 6-9 individuals / m 2 was observed during the survey. Adult and young S. variolaris were recorded during the survey but juvenile was not observed as they usually hide within the dead rocks. The mass aggregation appears to be due to seasonal occurrence that exploit intensive grazing on macroalgae during the post monsoon in Gulf of Mannar. This study also discussed the commercial importance of this edible sea urchin species which could be an important food sources for the coastal population of Gulf of Mannar.