Bleached staghorn coral in the Gobal Strait
under stress , and as part of a last-ditch attempt at survival , the coral expels its symbiotic algae , turning a skeletal white . The sight of a bleached reef is eerily beautiful , but the coral can only survive for so long without its zooxanthellae . The exact period is variable ; it could be anywhere between three and six weeks . But if the coral cannot stabilise and re-establish its algae , it dies .
At the time of my visit , the bleaching on the northern reefs was the most widespread I have ever witnessed in the Red Sea , but other locations were even worse . Our liveaboard host , marine biologist Dr Elke Bojanowski , told us that all the shallow coral on the offshore islands had bleached . Elke ’ s observations were subsequently confirmed by the Hurghada Environmental Protection and Conservation Association ( HEPCA ). Founded in 1992 , HEPCA is a respected non-governmental organisation devoted to the protection of marine life in the Red Sea .
Surveys , causes and the future
I sought out HEPCA ’ s Chief Scientific Advisor , Professor Mahmoud Hanafy , to ask if the phenomenon had indeed become more widespread . He said that in the previous bleaching events of 2012 , 2020 and 2023 , areas north of Qusier ( a coastal city in Egypt ’ s deep south ) had not experienced severe bleaching . “ This year and for the first time , all of the Egyptian reefs in the Red Sea are showing severe bleaching ,” Prof Hanafy said .
The corals affected are primarily shallow water stony corals , mainly species of Millipora , Montipora and Porites , the species most sensitive to heat stress . Also this year , high levels of bleaching were recorded in Acropora corals .
HEPCA has tagged more than 500 severely bleached coral colonies to assess their recovery rates based on species , geographical location and water depth . Evaluations are planned for November , but there is some encouraging news already , as field observations have shown clear signs of recovery .
Egypt has been held up as a location where reef building corals are especially resilient ; diving and scientific communities alike will be hoping that any lasting damage from this year is minimal . Prof Hanafy says : “ I have always strongly believed , along with other scientists , that the corals of the Egyptian Red Sea could be among the last coral refuges globally , largely due to the unique hydrodynamic patterns in the northern region . However , this year ’ s event suggests that these patterns might be changing . If true , it could make Egyptian corals more vulnerable to heat stress and bleaching in the future , something I sincerely hope does not happen .” �
■ With thanks to M / Y Scuba Scene and tour operator Oyster Diving oysterdiving . com
Sea anemones also suffer from bleaching
HEPCA ’ s Professor Mahmoud Hanafy on coral bleaching
“ This year ’ s bleaching event is notably different from the previous occurrences in 2012 , 2020 , and 2023 , which followed a consistent pattern along the Egyptian coast of the Red Sea . In past events , the northern region — covering the Gulf of Suez , Gulf of Aqaba , and Northern Egyptian Red Sea — experienced minimal bleaching , while the potential for bleaching increased further south , peaking around Marsa Alam .
The question of why Egyptian Red Sea corals show higher heat tolerance is still being studied . Some suggest evolutionary or genetic factors , but regional differences challenge this idea . I propose that reduced bleaching in the northern Red Sea is due to :
1 . Hydrodynamic patterns : The current flows from south to north at the northern extremity , creating a turbulence zone that mitigates temperature rise , protecting the area from severe bleaching .
2 . Wind patterns : Predominant northern and north-eastern winds push warmer surface water south , allowing cooler deep water to replace it in coral reef areas .
3 . Evolutionary adaptation : Corals in this region experience extreme temperature fluctuations , which may have increased their tolerance to heat stress .
This year , signs of changing water currents have been observed , including unusually low tides in July and weak winds and currents in June and July , resulting in calm seas . These shifts raise concerns about whether climate change might affect hydrodynamic patterns , potentially leading to more severe bleaching in the future .”
45