Mass coral bleaching events are making it harder for some reef fish to identify competitors, new research reveals.

Warmer ocean temperatures due to climate change mean some of the biggest coral reefs in the world have now been bleached.

Scientists from the University of Lancaster studied reefs across five Indo-Pacific regions and found that the ability of butterflyfish to identify competitor species and respond appropriately was compromised after widespread loss of coral caused by bleaching.

The study notes that this change means reef fish make poorer decisions that leave them less able to avoid unnecessary fights, using up precious limited energy.

Dr Sally Keith, a Senior Lecturer in Marine Biology at Lancaster University, said: “By recognising a competitor, individual fish can make decisions about whether to escalate, or retreat from, a contest – conserving valuable energy and avoiding injuries

“By looking at how behaviour responds to real-life changes in the environment and by seeing that those changes are the same regardless of location, we can start to predict how ecological communities might change into the future.

“These relatively small miscalculations in where to best invest energy could ultimately push them over the edge.”