Mass mortality of regular sea urchin Salmacis virgulata L. Agassiz and Desor, 1846 at Dhanushkodi, Southeast coast of Tamil Nadu, Gulf of Mannar, India

Abstract

Mass mortality of sea urchin, <em>Salmacis virgulata</em> scattered over the periphery of Dhanushkodi beach, was observed on February 13, 2019. More than 100 numbers of recently dead and dying specimens were found within a 10 m² area on the sandy beach. Beach profiles indicated several hundreds of exoskeletons of previously dead <em>S. virgulata</em> were washed ashore and buried in sand and withering seagrass. The causative agent responsible for mass mortality of <em>S. virgulata</em> is yet to be discovered. However, observations on wave approach toward shore indicated possible evidence that it could be due to a combination of strong nearshore waves and currents. This observation raises a critical research concern to investigate etiology of <em>S. virgulata </em>for species conservation.