Mass coral bleaching events caused by ocean warming are devastating reef ecosystems, causing welfare harm to corals and the billions of animals that depend on them.
Coral bleaching creates a cascade of welfare harms. Corals themselves, as animals, likely experience physiological stress during bleaching events - their zooxanthellae expelled, they are essentially starving while expending energy on immune responses to disease. The fish, octopuses, sea urchins, starfish and other reef residents lose the structural complexity that provides food and refuge from predators. Mass bleaching followed by reef death creates an impoverished urchin or algal rubble habitat supporting a fraction of the reef's former animal diversity and abundance. The welfare of billions of individual reef animals - in pain, stressed, starving or killed by reef collapse - makes climate-driven coral bleaching one of the largest animal welfare crises in history.