Saudi Red Sea - Abu Ejeiah (Thuwal)
Part of the regional summaries: Saudi Arabia - Jeddah / KAUST (Thuwal) / Rabigh, Saudi Arabia, and Red Sea
2024-02-23
2024-07-26
2024-10-04
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Al Madinah and Makkah (NOAA CRW virtual station)Abu Ejeiah is a steep offshore Thuwal reef surveyed repeatedly through the 2023-24 Red Sea bleaching event, its coral concentrated in dense pocilloporid and small-Acropora clusters on ridges separated by wide aprons of bare rubble and pavement — a mosaic that keeps published cover modest (15%). Its photographs from September 2023, February 2024, and July 2024 all show a slope crowded with fish, the July frames with scattered bleached colonies and patches among mostly pigmented coral, and the paper reports bleaching ranging from 13% to 69% of coral tissue across the four visits.
أبو عجيعة شعاب بحرية شديدة الانحدار قبالة ثول، مُسحت مرارًا خلال حدث ابيضاض البحر الأحمر في 2023-24، ويتركز مرجانها في عناقيد كثيفة من البوسيلوبوريات وAcropora الصغيرة على حواف تفصلها مساحات واسعة من الأنقاض والرصيف العاري - فسيفساء تبقي التغطية المنشورة متواضعة (15%). وتُظهر صورها من سبتمبر 2023 وفبراير 2024 ويوليو 2024 جميعًا منحدرًا يعجّ بالأسماك، وفي إطارات يوليو مستعمرات ورقع مبيضّة متناثرة بين مرجان مصطبغ في معظمه، وتفيد الورقة بأن الابيضاض تراوح بين 13% و69% من نسيج المرجان عبر الزيارات الأربع.
ترجمة هذا الملخص بالذكاء الاصطناعي؛ النص الإنجليزي هو المعتمد.
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Note: NOAA's regional station series averages 1.9°C warmer than the satellite pixel nearest this site (2.3 km away), which is used here instead.Two independent survey stations are described below; 1 of them is shown with the program’s logo — click one to see how far it is from this site. The other one has no mapped position.
8 of the 19 photographs on this page are shown beside the text that discusses them under "Site description" below.
Site description
Setting
A steep offshore fringing reef in the Thuwal complex, worked repeatedly between September 2023 and October 2024 with Coastline (KAUST) and photographed on all four visits.
General benthic features
The reef itself is a consolidated limestone slope that drops steeply into blue water, and the photographs read as a mosaic rather than a continuous carpet: dense clusters of pocilloporids (Stylophora- and Pocillopora-type, several in the deep magenta and lavender color forms characteristic of the central Red Sea) and small corymbose Acropora sit on ridges and buttresses, separated by wide aprons of coralline-crusted pavement and coral rubble that carry almost nothing (e.g., Image 1, Image 7, Image 8, Image 9).
Massive corals are the other structural element — cream-and-olive Porites boulders, encrusting-to-columnar Goniastrea and other faviids, Astreopora-type domes, and small fungiids wedged into the pavement (e.g., Image 3, Image 4, Image 5).
Soft coral is present but minor, mostly xeniid and low leathery colonies. The July 2024 frames show the same steep living slope crowded with fish, with branching, tabular, and massive colonies and scattered bleached colonies and patches across the wall and slope, among mostly pigmented coral; only a few frames are rubble flats.
Coral cover
- Reference: Mayfield (2025)
- Data file: (Mayfield, 2025-appendix A)
- CoralNet submission package (accession #5546)
- 15% ± 14% SD across 417 photographs.
- This is the published CoralNet point count from Anderson's own paper (most frames annotated by CoralNet's AI, trained and checked by the author), and it is not re-derived here.
Stressors
The site is part of the published 2023-24 Red Sea bleaching series (Mayfield 2025, Environments 12:248).
Fish and other fauna
September 2023 and February 2024 show a busy slope crowded with fish with schooling anthias and chromis pouring over the ridge, and dolphins recorded in Anderson's dive log and field notes from the same days (e.g., Image 2); a blue-fin trevally (Caranx melampygus) hunting the base was photographed in July 2024.
Comparisons with other data
Robitzch & Berumen (2020) surveyed a nearby station (Al Fahal, reef 2), 0.05 km from the pin. Within 5 km, two independent stations recorded station-year means of 26–40% hard coral cover between 2013 and 2015; the nearest of these, Khalil et al. (2017), 1.05 km away, read a mean of 26% in 2013.
Dive record
Three logged dives with Coastline (KAUST) between September 2023 and October 2024: 2 September 2023, 23 February 2024, and 4 October 2024; the July 2024 visit has no dive-log entry. The photographed visits are visibly different.
Survey summary
Abu Ejeiah: surveyed 4 times, Sep 2023–Oct 2024; bleaching ranged from 13% to 69% of coral tissue across visits (CoralNet point counts; Mayfield 2025, Environments 12:248). Surveyed in partnership with Coastline (KAUST).
CV model comparison
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The reference is this dive site's own published CoralNet point count by the author (Mayfield 2025, Environments 12:248, Appendix A; most frames annotated by CoralNet's AI, trained and checked by the author). The computer-vision rows are this site's own values: Claude is a blind point count of all of the site's edited photographs, DINOv3 ran on the site's benchmark frames (the photographs the author annotated point by point), and CoralSCOP is the site's finished survey of its edited photographs. They are on different frame sets from the published count, a row under 30 frames is indicative only, and no computer-vision method yet estimates coral cover accurately on new images.| Method | Hard coral cover (%) | Photos (n) ± SE |
|---|---|---|
| Published point count (CoralNet-assisted) | 15.2 | |
| In-house DINOv3 | too few photos (n=4) | |
| CoralSCOP edited | 24.3 | n = 367 |
| Claude (edited photos) | 17.4 | n = 366 · SE 0.8 |
The two computer-vision methods agree within 6.9 pp (17.4–24.3%) and read 2.2–9.1 pp above the published point count (15.2%); the headline is the published point count because it is the site's published value (CoralNet-assisted: most frames were annotated by CoralNet's AI, trained and checked by the author).
In-house DINOv3: this method was run on 4 of 417 photos, under the 10 needed for a value, so it is not shown and is left out of any mean; every other row rests on its own photo count.
See a more detailed, stand-alone version of this table.
Dive history
| Date | Time in | Max depth (m) | Bottom time (min) |
|---|---|---|---|
| 2023-09-02 | 11:00 | 13.5 | 55 |
| 2024-02-23 | 10:44 | 18.6 | 53 |
| 2024-10-04 | 10:12 | 19.8 | 56 |
Independent surveys nearby
| Agency / program | Year(s) | Stations / distance | Link |
|---|---|---|---|
| Khalil et al. (2017) | 2013 | 1 station, 1.05 km | Records ↓ |
| Monroe et al. (2018) | 2015 | 1 station, 1.31 km | Records ↓ |
Coral Reef DiagnosticsYear-average (illustrative only, programs differ)Within 5 km, 2 independent survey stations recorded hard coral cover in 3 records between 2013 and 2015. The most recent nearby survey is from 2015, so these values predate recent heat stress. This site's own estimate (15%) sits 11 points below the range of these station-year means (26–40%); the methods differ, so the comparison is context, not a like-for-like test.
Collected by other programs using different methods, so these are context for the figures above, not a like-for-like comparison. Where a station was surveyed more than once, the cell shows either the range of its values or, as a single value, the mean of surveys made in one year. Station names are not dive-site names.
| Agency | Site / location | Date | Hard coral cover (%) | Distance | Link |
|---|---|---|---|---|---|
| Khalil et al. (2017) | — | 2013 | 26% (2 records) | 1.05 km | doi:10.7717/peerj.3410 |
| Monroe et al. (2018) | Al Fahal (Midshelf 1), Thuwal, central Saudi Red Sea | 2015 | 40% | 1.31 km | doi:10.1371/journal.pone.0195814 |
Data & links
- CoralNet image repository for this region ↗
- Photo portfolio ↗
- Photo portfolio ↗
- Coral Reef Diagnostics country page ↗
All images from Coral Reef Diagnostics. Data are from Coral Reef Diagnostics and the organizations named in the data sources above.
© Coral Reef Diagnostics.
References
- Mayfield AB (2025). Using Tourist Diver Photos to Assess the Effects of Marine Heatwaves on Central Red Sea Coral Reefs. Environments 12:248. PDF
- Khalil MT, Bouwmeester J, Berumen ML (2017). Spatial variation in coral reef fish and benthic communities in the central Saudi Arabian Red Sea. PeerJ 5:e3410. DOI
- Robitzch V, Berumen ML (2020). Recruitment of coral reef fishes along a cross-shelf gradient in the Red Sea peaks outside the hottest season. Coral Reefs 39:1565-1579. DOI
- Monroe AA, Ziegler M, Roik A, Röthig T, Hardenstine RS, Emms MA, et al. (2018). In situ observations of coral bleaching in the central Saudi Arabian Red Sea during the 2015/2016 global coral bleaching event. PLOS ONE 13:e0195814. PDF