Coral bleaching occurrence along the Egyptian coast of the Red Sea during the summer heat stress period, 2020 | ||||
| Egyptian Journal of Aquatic Biology and Fisheries | ||||
| Article 2, Volume 25, Issue 5, September and October 2021, Page 17-37 PDF (1.46 MB) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/ejabf.2021.196904 | ||||
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| Author | ||||
| Muhammad Y. A. Dosoky et al. | ||||
| Abstract | ||||
| The Red Sea is considered one of the few environments that accommodate a wide diversity of thermotolerant corals. However, the recent bleaching events had revealed that some Red Sea coral species may be under threat and may face a more dramatic future. Here, we investigate the pattern of bleaching in hard corals inhabiting the Egyptian coast of the Red Sea (from Hurghada, at the north, to Wadi El-Gemal, at the south) during the 2020 summer heat stress period. Field data on the cover, number of colonies, and severity of the bleaching were collected using the line-intercept transect method from three geographical sectors (each contains two study sites), two depth ranges (0-5m and 10-15m), and two reef systems (inshore and offshore reefs) during the period from September to October 2020. The results indicated that the bleaching symptoms of different severities had appeared on 32.74% (460/1405) of the total examined colonies (36.66% of the total coral cover). Our survey, however, revealed that corals in the southern reefs (Sector_3) were more susceptible to bleaching than those present in the north (Sector_1). We also noted that the bleaching intensity was more concentrated between 0-5m, while colonies beyond 10m were more sheltered. In contrast, the results revealed that both inshore and offshore reefs were vulnerable to bleaching with no effect for the distance from the shore on coral resistance. Furthermore, the results indicated that coral genera like Millepora, Montipora, Pocillopora, Acropora, and Porites showed high bleaching cover and severity whereby they may be more threatened by the thermal stress than the others. In the light of these results, the current study provides field evidence on the potential role of the northern reefs as a refugium for the Red Sea corals and suggests that the high latitudinal reefs may be the last to decline due to climate change. On the other hand, the recorded bleaching pattern at the southern coasts, albeit less acute, may raise the concern on the vulnerability of these reefs to the heat stress than was expected. | ||||
| Keywords | ||||
| Coral bleaching; Bleaching severity; Thermotolerant corals; Global change; Red Sea; Egypt | ||||
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