Mass mortality of diadematoid sea urchins in the Red Sea and Western Indian Ocean.

Sea urchins are primary herbivores on coral reefs, regulating algal biomass and facilitating coral settlement and growth. Recurring mass mortality events (MMEs) of Diadema species Gray, 1825 have been recorded globally, the most notorious and ecologically significant of which occurred in the Caribbean in 1983, contributing to the shift from coral to algal-dominated ecosystems. Recently, first evidence of Diadema setosum mass mortality was reported from the eastern Mediterranean Sea.