Long-term coral reef monitoring programs have been established and used efficiently in many parts of the world to assess the state of coral reefs under increasing anthropogenic pressures and natural disturbances, as well as to evaluate the efficiency of established marine protected areas (MPAs) or other conservation strategies. Over the past decade, Red Sea coral reefs have experienced two major bleaching events in 2010 and five years later, in 2015/2016, with severe coral loss along the central and southern Saudi Arabian coast. With this study we present the first characterization of fish community changes through time in the Red Sea. Fish abundance data from twenty-three reefs from two different regions in Saudi Arabia, central (Thuwal) and south-central (Al Lith), surveyed between 2008 and 2019 were examined. A significant decline of hard coral was observed on nearshore reefs in both regions following two bleaching events. The results revealed a persistent cross-shelf partitioning of fish communities before and following a substantial drop in coral cover. Offshore reef fish communities appeared to be more stable and homogeneous through time, whereas nearshore reef fish communities had less similar composition throughout the study period. Species-specific analyses revealed the decline in the abundance of several obligatory corallivorous species, a contrasting response from most herbivore fish species that generally experienced an increase in their abundance since 2008. These findings indicate that the bleaching events from this period had less effect on communities as a whole, but instead cause changes in abundance in several key species, mostly affected by coral loss and subsequent algal increase. While a well-structured and standardized long-term monitoring system is yet to be established for Saudi Arabian coral reefs, our findings provide a sound baseline of fish assemblages over the last decade. These findings are critical for future studies as well as effective conservation strategies in the face of ongoing coastal developments, overfishing and climate change.
|Date of Award
- Biological, Environmental Sciences and Engineering
|Michael Berumen (Supervisor)