Assessment of Seasurface Temperature Affecting Coral Bleaching in the Eritrean Southern Red Sea

Abstract

Coral reefs, a spectacular marine ecosystem, have species diversity that significantly exceeds any other marine environment. However, they are among the most heavily degraded and sensitive marine ecosystems. In the literature, there is little information about coral reef distribution and oceanographic factors influencing reef health. To generate preliminary data on the Eritrean southern Red Sea, to serve as a baseline for future coral reef management and monitoring initiatives, two sites from around Massawa, and one around Dahlak Island, Eritrea were selected to collect data on coral reef distribution and bleaching which was used as a benchmark for the data obtained from a satellite. A line intercept transect method was employed to survey the benthic communities. Three imagery classification methods (MLC, Random Forest, and SVM) were employed to assess the distribution of the different benthic habitats. The SVM model had the highest classification accuracy of 74%. The study showed that there was a remarkable decline in live coral cover between the years 2013 and 2020. Results from MANOVA and ANOVA tests illustrate a significant difference in live and dead coral coverage among the three sites. Furthermore, time series analysis on the sea surface temperature (SST) and sea surface temperature anomaly (SSTA) data indicated a significant increase in sea surface temperature around the southern red sea, and it is predicted that this trend will continue in the next 10 years. Results from this study indicate that the reefs around Massawa show a rapid decline in live coral cover, hence, the study calls for the instigation of management plans towards the conservation of coral reefs in the region.