Kuwait Diving Team: Coral Bleaching Rate in Arwan Very Low and Within Annual Average

By Zuhra Al-Kazemi, Kuwait City, Sept 30 (KUNA) — The Kuwaiti diving team affiliated with the Environmental Volunteer Foundation (Al-Mubra) confirmed on Wednesday that the level of coral bleaching in the Arwajan reef patch is very low and within the annual bleaching rate.

Mahmoud Ashkanani, the team’s environmental projects manager, told KUNA that coral and reef monitoring is ongoing, particularly following the end of the marine heatwave period that lasted from July 21 to late August.

Ashkanani explained that inspections revealed the bleaching was limited to only four coral species: *Acropora muricata* (honeycomb coral), *Acropora cytherea* (grooved acropora), *Acropora gemmifera* (smooth acropora), and *Pocillopora damicornis* (grooved cauliflower coral).

He added that the team observed a black band phenomenon in a colony of *Acropora cytherea*, a disease known as "Black Band Disease." This appears as a distinct band separating living tissue from dead tissue. The black band consists of microscopic microbes made up of various bacteria that release hydrogen sulfide compounds and other toxins, depriving coral tissues of oxygen, poisoning them, and causing immediate death.

Regarding factors that stimulate the emergence of these microbes, Ashkanani stated they are linked to rising water temperatures. "Thermal stress and deteriorating water quality reduce coral immunity, making them susceptible to these bacterial attacks," he said.

The team recommends continued scientific monitoring and warns divers to avoid touching the black band with hands or equipment to prevent the transmission of bacterial infections to other healthy coral colonies.

Ashkanani noted that the coral condition there is thriving, according to monitoring data from the Coral Watch program at Australia’s University of Queensland. The colors indicate coral health and recovery. Although levels have not yet returned to those seen before 2010, they serve as a strong indicator that corals are adapting to record-high temperatures.

Water temperatures were recorded at 33.3 degrees Celsius near the surface, with a low of 31.6 degrees Celsius at a depth of 10.2 meters. Most colonies experiencing total bleaching are located at depths greater than 8 meters, while those near the surface, at around 2.6 meters, are in the shallowest parts of the reef and appear healthy and vibrant.

Ashkanani pointed out that Kuwait’s reefs have suffered several major bleaching events over the past three decades, specifically in 1998, 2010, 2015, 2016, and 2020.

He explained that bleaching occurs when zooxanthellae, algae that live within coral tissues, are expelled due to heat-induced stress. This causes the coral to lose its color, which it derives from these algae, becoming translucent and revealing the white calcium carbonate skeleton beneath.

Furthermore, corals lose more than 75 percent of their food supply, which is provided by the algae through photosynthesis. This process involves absorbing carbon dioxide from the water and light, converting them into carbohydrates. If conditions do not return to normal, the coral will die, with the duration of stress directly impacting mortality.

The Arwajan reef is Kuwait’s second-largest coastal reef patch after the Al-Zour patch. Located 14.5 kilometers southeast of Al-Fahaheel and nine kilometers east of the Abdullah Port coast, it has an oval shape, a maximum length of 625 meters, a width of 480 meters, a perimeter of 1.8 kilometers, and an area of 221,000 square meters.

Its reefs are characterized by the Acroporidae family, particularly *Acropora cytherea*, featuring large sizes, significant heights, and dark colors that distinguish them from similar species in other reefs. Their sizes vary, with some peaks of these coral masses reaching just one meter below the water surface in the shallowest areas. The reef also features knobby hump coral.

Additionally, the team noted the presence of green sea fan coral and sea pen coral on the sandy bottom surrounding the reef to the west. A navigational beacon and the wreckage of a trailer are located on the eastern side at a depth of ten meters.

Ashkanani mentioned that the team identified more than 19 species of coral and over 36 species of organisms and fish. They also installed and secured six mooring buoys along the eastern boundary for recreational use and established two artificial coral colonies in the surrounding area.

(End) Z.H. / A.N.D.