Effects of Habitat Connectivity and Complexity on the Distribution of Inshore Reef Fish Communities

Coastal seascapes that are comprised of highly connected and complex habitats typically support a greater diversity and abundance of fish. Nearshore reef systems that are close to the coastline and therefore nearby human disturbances are, however, under significant and increasing threat from further disturbance such as commercial and recreational fisheries. In this study, inshore rocky reef fish communities were surveyed at 65 sites in eastern Australia, using baited remote underwater video stations (BRUVS) and unbaited remote underwater video systems (RUVS) with the aim of determining the spatial and habitat influences of fish communities on inshore rocky reefs and to identify whether the spatial patterns driving fish communities were consistent between BRUVS and RUVS. BRUVS were found to identify a greater abundance and diversity of fish and a greater abundance of fish from different functional groups (e.g. herbivores, omnivores, zoobenthivores and piscivores) than RUVS. Additionally, BRUVS and RUVS identified different spatial features that modified the structure of the assemblage; however, it was found that BRUVS and RUVS consistently identified seascape effects including positive impacts of reef extent and complexity and connectivity to other habitats and negative impacts associated with proximity or the extent of urbanisation nearby. The results show that the relative importance of the seascape is a constant between sampling methods, but the methods used here do not identify those patterns consistently. We did however see that fish communities were consistently more abundant and diverse on reefs that were larger in extent and more complex, while being mediated by urbanisation.