Saudi Red Sea - Anderson's Reef-II (Jeddah)
Part of the regional summaries: Saudi Arabia - Jeddah / KAUST (Thuwal) / Rabigh, Saudi Arabia, and Red Sea
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Al Madinah and Makkah (NOAA CRW virtual station)A Jeddah reef whose set piece is a bommie the size of a small building upholstered in lilac, mauve, and gold soft corals, with anthias and glassfish swarming above it. The surrounding hard coral is dense and colorful, including a very large branching Acropora colony with a broad bleached margin; the site record reports 19% of coral tissue bleached in August 2024.
شعاب في جدة أبرز ما فيها كتلة مرجانية بحجم مبنى صغير مكسوة بمرجانيات لينة بلون الليلك والبنفسجي الفاتح والذهبي، تحوم فوقها أسراب الأنثياس والأسماك الزجاجية. والمرجان الصلب المحيط كثيف وملون، ومنه مستعمرة Acropora متفرعة كبيرة جدًا حافتها العريضة مبيضّة؛ ويفيد سجل الموقع بابيضاض 19% من نسيج المرجان في أغسطس 2024.
ترجمة هذا الملخص بالذكاء الاصطناعي؛ النص الإنجليزي هو المعتمد.
One independent survey station shown with the program’s logo — click one to see how far it is from this site.
One other CRD dive site with its own page within 5 km shown in orange — click a marker to open its page.
5 of the 20 photographs on this page are shown beside the text that discusses them under "Site description" below.
Site description
General benthic features
The set-piece here is soft coral. A diver alongside gave scale to a bommie the size of a small building, its entire crown upholstered in arborescent soft corals — lilac, mauve, cream, and pale gold Dendronephthya/Scleronephthya-type colonies with polyps fully extended in current — with a shimmering cloud of anthias and glassfish suspended over it. The hard coral reef around it is dense and warm-toned: pocilloporids in salmon, rose, apricot, and lilac packed shoulder to shoulder down the slope, tan and gold corymbose Acropora, blue-gray and cream Porites lobes, and faviid domes (e.g., Image 1, Image 2, Image 3, Image 4), and a very large branching Acropora (Anderson's identification) (e.g., Image 6).
Seen from above, that very large Acropora shows a striking two-tone pattern — olive-gold in the center and a broad bleached margin all the way round (Anderson) (e.g., Image 6).
Coral cover
- Reference: Mayfield (2025)
- Data file: (Mayfield, 2025-appendix A)
- CoralNet submission package (accession #5546)
- 21% ± 16% SD across 174 photographs.
Stressors
The site record reports 19% of coral tissue bleached at about 11.9°C-weeks DHW on the survey date (3 August 2024; NOAA Coral Reef Watch, Madinah-Makkah (Saudi Arabia) virtual station) — close to Reef-I's figure, and the two sit close enough to read as one reef system sampled twice.
Comparisons with other data
Apart from our own published survey shown here, we found no other surveys at this site as of 2026. Within 5 km, one independent station, Khalil et al. (2017), 3.81 km away, read a mean of 31% in 2013.
Dive record
The second of the two 3 August 2024 dives off Jeddah with Al-Haddad SCUBA, on the neighboring reef about 500 m north of Reef-I.
CV model comparison
More info
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) | 21.0 | |
| In-house DINOv3 | too few photos (n=3) | |
| CoralSCOP edited | 24.9 | n = 174 |
| Claude (edited photos) | 19.1 | n = 175 · SE 1.1 |
The two computer-vision methods agree within 5.8 pp (19.1–24.9%) and read within 3.9 pp of the published point count (21.0%).
In-house DINOv3: this method was run on 3 of 175 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.
Independent surveys nearby
Within 5 km, 1 independent survey station recorded hard coral cover in 2013. The most recent nearby survey is from 2013, so these values predate recent heat stress. This site's own estimate (21%) is not compared with these surveys: none lies within 2 km.
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 | 31% (2 records) | 3.81 km | doi:10.7717/peerj.3410 |
Data & links
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
- 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
- Mayfield AB (2025). Using Tourist Diver Photos to Assess the Effects of Marine Heatwaves on Central Red Sea Coral Reefs. Environments 12:248. PDF