Description
Coral reef ecosystems are increasingly threatened by anthropogenic stressors. In particular, plastic pollution can cause entanglement injuries, habitat smothering, and can be consumed when mistaken for food. Although physical impacts of plastic pollution have been studied, the behavioral effects on fish communities remain largely unexplored. We examined the behavioral responses of Stegastes nigricans, a territorial herbivorous damselfish, to plastic trash that can enter coastal waters in Mo’orea, French Polynesia. We conducted 109 thirty-minute experimental trials, video recording behavioral responses (circling, hovering, biting, charging, removing, camera interaction, and “ambient activity”) to three different sized empty chip bags and two experimental controls, one with nothing and the other a common seaweed. Results revealed that fish exhibited significantly (p = 0.002-1.000) higher levels of aggressive behaviors, inspecting, biting, charging and removing all items placed in their territories. We also observed a trend of increased interactions with the smallest trash, which we believe is due to the fact that this trash is smaller than the fish. The presence of trash amplified overall aggressive behavior, demonstrated by increased aggression towards objects outside of the territory, like the camera, raising concerns that fish may spend excessive time reacting to trash instead of engaging in essential activities like growth and reproduction. This study highlights the need to expand on behavioural studies on the threat plastic waste poses to fish and other marine life.