Possible effects of changes in sea level on coral communities, and the abundance and distribution of territorial reef fish

Reef flats are among those habitats which are most susceptible to climate change. Climate change is predicted to impact coral reef flats by changing various characteristics including sea levels. This research investigated the... [ view full abstract ]

Reef flats are among those habitats which are most susceptible to climate change. Climate change is predicted to impact coral reef flats by changing various characteristics including sea levels. This research investigated the effects on reef fish assemblages of these changes by using the hydrodynamic effects of engineering works as a surrogate for the effects of future climate change. Data were collected around Heron Island situated on the leeward side of the western end of Heron Reef platform. Due to engineering works related to reef rim blasting and creation of the channel to improve access to the island, the area around the channel was first affected by a decrease in sea level. Following two-stage construction of the bund walls to reduce the low-tide run-off through the channel caused the local sea level rise that were analogous to changes predicted as a consequence of climate change. This research provides the analysis of the influence of changes in the characteristics of coral reef environment on coral cover, and the abundance and distribution of reef fish to detect the response of teleost reef fish to the changes in coral cover conditions likely to result from sea level rise. Pomacentridae and Chaetodontidae families were selected as target species for the fish survey as the indicators of the state of corals due to their strong associations with coral colonies and territoriality. The results confirmed the influence of the hydrodynamic effects of engineering works (channel and the bundwalls) as a surrogate for the effects of future climate change on coral conditions. The complexity of coral-reef habitats was considered in terms of live coral and a structural complexity. The response of teleost reef fish was not related to the changes in sea level directly but was strongly related to coral conditions. The results demonstrated a positive correlation between the percent area of live corals and target fish abundance. This research can provide the basis for future investigations for better understanding the processes and effects analysed in this research.