Humphead Parrotfish

Photo: Mark Rosenstein · CC BY-NC

Huge schools of humphead parrotfish surge through the pass at dawn and dusk, their combined biting of dead coral producing an audible crunching and generating several tonnes of white sand per school per year. Individual fish reach 130 centimetres and move in tight formations of 20 to 50 animals, bulldozing across the reef crest in a way that shapes the physical structure of the surrounding reef. Mayotte is one of the few Indian Ocean sites where truly large schools of this endangered species still occur regularly.