Mass coral bleaching makes it difficult for some reef fish species to identify competitors. This was reported by the press service of Lancaster University.
Researchers studying reefs in five regions of the Indo-Pacific have found that the butterflyfish’s ability to identify competing species and respond appropriately to them is impaired following massive coral death caused by bleaching. As a result, they make bad decisions that make it harder for them to avoid unnecessary fights by wasting their limited energy resources.
Scientists believe these changes could affect the survival of the species, as further global warming is more likely to exacerbate the bleaching problem.
Researchers conducted more than 3,700 observations and compared their behavior on 38 species of butterflyfish on the reefs before and after coral bleaching. After the death of corals caused by bleaching, signaling between fish of different species began to deteriorate and encounters between different species turned into chases in more than 90% of cases compared to 72% before bleaching. The researchers also found that the distance of these chases increased after bleaching: The fish began to expend more energy chasing their opponents.
Researchers believe environmental disturbances affect fish behavior because coral deaths are forcing species to change their diet and habitat. Therefore, these large-scale environmental changes disrupt the well-established evolutionary relationships that have allowed multiple fish species to coexist without major conflict.