Age: A CORAL killer that has wreaked havoc along the Great Barrier Reef is threatening part of the "coral triangle" – the world’s richest centre of coral reef biodiversity. Marine surveys in Halmahera, Indonesia, last month revealed the crown of thorns starfish has almost completely destroyed some of the region’s stunning reefs. The predatory starfish feeds on corals by spreading its stomach over them and secreting an enzyme that breaks down the coral tissue. About …