An individual will depend on the outcomes of their interactions with conspecifics and heterospecifics to both survive and thrive in its environment. Interactions are the cause for much of the behaviour we see in the natural world and animals have the capacity to both detect and create signals across various sensory modalities. This multimodal signalling allows for more complex interactions with others. It is especially important in dynamic environments where important information between signaller and receiver might be lost. Coral reef environments are both a hotspot of interactions and one of the most heavily impacted ecosystems by anthropogenic change. Anthropogenic stressors alter environments in unprecedented ways, there is therefore increasing urgency to better understand how multi-stressor impacts change behavioural interactions between individuals. In this thesis, I combine behavioural observations with manipulative field experiments to firstly explore how wild species of coral reef fish use their multisensory interactions, and secondly how interactions with conspecifics and heterospecifics are impacted by multiple stressors. In Chapter 2, I demonstrate that the social context experienced by individual Ambon damselfish (Pomacentrus amboinensis) can affect their behavioural responses and multimodal displays towards conspecific and predatory threats. In Chapter 3, I demonstrate that both the individual behaviour and social interactions of orangefin anemonefish (Amphiprion chrysopterus) are impacted by the multiple stressors of anemone bleaching and acute motorboat noise. Anemonefish anti-predator behaviour tended to be less appropriate when exposed to dual stressors and motorboat noise significantly affected behaviour towards conspecifics and heterospecifics at bleached but not unbleached sites. In Chapter 4, I demonstrate that cleaner wrasse (Labroides dimidiatus) heterospecific cleaning interactions with their clients are significantly impacted by chronic habitat degradation and acute motorboat noise exposure. In the onset of motorboat noise, both stressors impacted cleaner wrasse investment in cooperative behaviours, responsiveness to clients and cleaning behaviour. Immediately after the cessation of motorboat noise, both stressors continued to impact cleaner wrasse cooperative and antagonistic interactions, indicating that dual stressor impacts can have delayed effects. This research demonstrates that coral reef fish behaviour and interactions are complex and flexible across multiple sensory modalities but also that both positive and antagonistic interactions are impacted by a changing world.
Fish Interactions in Coral Reefs: from Multiple Senses to Multiple Stressors
Davidson, I. K. (Author). 5 Dec 2023
Student thesis: Doctoral Thesis › Doctor of Philosophy (PhD)