The 2016 global coral bleaching event made some reef fish too weak to fight for food, researchers say, after seeing a major reduction in aggression between members of territorial, coral-eating species.
Scientists led by Sally Anne Keith, a marine biologist at Lancaster University, documented 3,828 encounters between 38 species of butterflyfish on 17 reefs in the central Indo-Pacific region, before and after the bleaching event.
“Aggression between butterflyfishes decreased by two-thirds following large-scale coral mortality, despite no significant change in fish abundance or community composition,” they said in a report in the journal Nature Climate Change.
“Reduced aggression could indicate the breakdown of territories among butterflyfishes, as individuals roam further to obtain enough resources, rendering investment in aggressive defence too costly and potentially causing a shift from interference to exploitative competition,” they said.
