MEPS 589:179-192 (2018)  -  DOI: https://doi.org/10.3354/meps12423

ABSTRACT: The ability to understand the functioning of ecosystems requires an understanding of the role individual or groups of species play within that environment. Defining ecological roles is challenging in complex ecosystems such as coral reefs. While it is well known that multiple reef-associated shark species coexist on a single reef, their patterns of space use and interactions have been difficult to define. Here we used acoustic telemetry data to analyse activity space, depth use and spatial networks to examine the interplay of these species relative to their roles in coral reef ecosystems. Integration of multiple analyses revealed that species with similar sizes and similar diets displayed clear spatial segregation, both between habitats and depth. This distribution is likely to reduce competition for prey among these species. In contrast, species that are dietary generalists or that have unique diets moved more broadly and overlapped with all other species. These results suggest competition for prey may be a driving factor in the distribution and space use of reef-associated sharks, revealing complex, interdependent functional roles within these systems. Results of this analysis demonstrate the advanced information that can be obtained through application of multiple methods and directed, simultaneous study of multiple species.

KEY WORDS: Acoustic tracking · Carcharhinus · Galeocerdo · Triaenodon · Hemigaleus · Network analysis · Kernel utilisation distribution · IMOS Animal Tracking Facility