Abstracts:

Waves affect escape performance in juvenile coral reef fishes: Locomotion is an integral component of predator-prey interactions and fundamental to the survival of mobile organisms. In fishes, for example, the fast-start escape response is used for escaping from predators. This behaviour is critical for juvenile reef fishes as predation is one of the dominant factors influencing their survivorship and distribution in nature. In shallow coastal habitats, wave action is a powerful physical force thought to exert significant effects fish locomotor performance. My PhD research examines how complex, wave-driven water flows can influence the outcome of predator-prey relationships. Using laboratory experiments and high-speed kinematic analyses, I examined how unsteady, wave-driven water motion affects the fast-start performance of juvenile coral reef fishes. I compared three species with contrasting body morphologies since deep bodies are thought to improve postural control and maneuverability compared to fusiform bodies. Unsteady flow had little effect on maximum escape velocities but dramatically altered response times for some species and not others. Since response latency is a major determinant of escape success, postural disturbances from unsteady water motion might reduce the ability of some coral reef fishes to evade predators during settlement. This could have important implications for the distribution, abundance and recruitment of juvenile fishes on the reef, across both spatial and temporal scales.

Waves shape intraspecific variation in a widespread damselfish: Wave-driven water flow is a major environmental factor limiting the distribution and abundance of marine organisms in shallow aquatic habitats. Distribution patterns of many coral reef fishes have been linked to their swimming performance across wave energy gradients, suggesting that species are limited to specific habitats according to these features. Yet, some widespread species are routinely found across habitats ranging from sheltered lagoonal fringing reefs to the exposed crests of barrier reefs. How are these species able to thrive in such a broad range of wave environments? As part of my PhD research, I am exploring the swimming performance of the spiny chromis, Acanthochromis polyacanthus, a common and widespread damselfish on the Great Barrier Reef in Australia. Using a combination of behavioural observations, morphological measurements, respirometry and rearing experiments, I will describe the intraspecific adaptations that allow this species to persist across such a diversity of flow environments as well as suggest proximate mechanisms contributing to this variation. Studying natural populations distributed across steep environmental gradients provide excellent opportunities for understanding factors contributing to diversity and the capacity of species to respond to environmental fluctuations..

Biographies:

Dom completed a joint master’s degree at McGill University in Canada and the Smithsonian Tropical Research Institute in Panama; he is currently in the final year of his PhD at the Australian National University. His research focuses on fish and invertebrates, both in marine and freshwater systems, and he has worked on invasive species, predation and host-parasite interactions. Currently, his thesis examines how complex water flows affect locomotion and predator-prey interactions in coral reef fishes.

Sandra completed her BSc Honours and MSc degrees in biology at McGill University, Canada. Her Masters thesis explored intraspecific variation and ecomorphology in East African cichlid fishes. In 2010, Sandra commenced her PhD at the Australian National University and is using techniques in ecomorphology, ecophysiology and behavioural ecology to explore inter- and intraspecific phenotypic variation in coral reef fishes in response to biotic (mostly parasite) and abiotic (mostly wave) gradients.