According to new research, mass coral bleaching events make it difficult for some reef fish species to identify competitors.
Scientists studying reefs in five Indo-Pacific regions discovered that after widespread coral bleaching, butterflyfishes’ ability to identify competitor species and respond appropriately was compromised. Because of this change, they make poorer decisions. These decisions made it more difficult for them to avoid unnecessary fights.
The researchers behind the study believe that these changes could have an impact on species survival as global warming increases the likelihood of coral loss.
The research is described in the paper “Rapid resource depletion on coral reefs disrupts competitor recognition processes among butterfly species.” It was published in the journal Proceedings of the Royal Society B.
The researchers compared the behaviours of 38 different species of butterflyfish on reefs before and after coral bleaching events.
Signaling between fish of different species became less common after the coral mortality event. Encounters escalated to chases in more than 90% of cases. The distance of these chases also increased after bleaching. Fishes were expending more energy chasing away potential competitors than they would have previously.
Environmental disturbances are affecting fish recognition and responses. Because bleaching events force fish species to change and diversify their diets and territories. As a result of these large-scale environmental changes, long-established and co-evolved relationships that allow multiple fish species to coexist are being disrupted.
Dr. Sally Keith, Dr. Lisa Boström-Einarsson, Dr. Ian Hartley of Lancaster University, Dr. Jean-Paul Hobbs of the University of Queensland and Prof. Nathan Sanders of the University of Michigan are the paper’s authors.