The coral reef in the Gulf of Eilat – Aqaba is a unique ecological system that provides diverse habitats extending to a depth of approximately 150 m and hosts thousands of species of fish and invertebrates. The coral reef is a fringing reef along the coastline, formed by biogenic construction (using calcareous animals), and it is one of the northernmost coral reefs in the world (Loya, 2004; Dubinsky & Stambler, 2011; DiBattista et al., 2016; Eyal et al., 2019).
In the Red Sea, approximately 365 species of scleractinian corals (hard corals) are documented, with a high endemic rate of about 5.5% (DiBattista et al., 2016), of which approximately 138 species have been recorded in the Gulf of Eilat (Kochzius, 2002). These corals engage in symbiosis with mutualistic algae called zooxanthellae (of the Symbiodinium genus), with only two genotypes, Clades A and C (Karako-Lampert et al., 2004). Around 30 species of soft corals (octocorals) have been recorded in the northern Gulf, and it has been found that species richness in mesophotic reefs (30-150 m) is higher than in shallow reefs (Shoham & Benayahu, 2017; Liberman et al., 2022).
The prominent coral predators (corallivores) in the Gulf of Eilat are snails of the genus Drupella, particularly the species Drupella cornus, and the crown-of-thorns starfish (Acanthaster planci) (Shafir et al., 2008; Stambler, 2013).
The live coral coverage percentage in the northern Gulf has been continuously monitored since 2004 and reached a maximum of about 26.4% in 2013. In the years that followed, it fluctuated between 24-25.3%. In March 2020, a powerful southern storm occurred, damaging the shallow reefs, and a decrease of approximately 1.5% live coral coverage per year was recorded over two consecutive years. Currently, the average live coral coverage in the Gulf stands at 22.6±3.2% (Shaked & Genin, 2023).
In recent decades, massive coral mortality has been documented across oceans following heatwaves, where sea temperatures were measured to be 1-2˚C above the local maximum summer temperature, leading to coral bleaching and death. The coral reefs in the Gulf of Eilat have shown resilience to climate change, attributed to evolutionary selection favoring genotypes resistant to higher temperatures (due to the arrival of corals in the northern Gulf from warmer areas of the southern Red Sea). Studies in the northern Gulf have examined the physiology of corals and changes in the energy reserves of both corals and their symbiotic algae under different scenarios of expected climate change. The findings show that common coral species in the Gulf of Eilat do not bleach and exhibit survival even at temperatures of about +5˚C above the local maximum summer temperature (Fine et al., 2013; Kochman-Gino & Fine, 2023). Therefore, the Gulf of Eilat serves as a refuge for coral reefs from climate change and a source for the dispersion of planulae (reproductive products) to southern reefs that have been affected in the Red Sea (Fine et al., 2013; Fine et al., 2019).
Despite the unique resilience of coral reefs in the Gulf of Eilat to climate change and their universal importance, these reefs face threats from local anthropogenic impacts, such as oil spills, nutrient enrichment, physical damage by divers, light and noise pollution, construction and development waste, plastic waste, heavy metal pollution, and more. Additionally, there are also natural stressors in the Gulf of Eilat, such as viral and bacterial infections, extreme low tides, and flash floods (Loya, 2004; Fine et al., 2019; Shaked & Genin, 2023).
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