Egypt Red Sea - Nakari House Reef-South (Marsa Nakari)
Part of the regional summaries: Egypt and Red Sea
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Egypt (NOAA CRW virtual station)Nakari House Reef-South, the first stop of the September 2024 Egypt survey leg, captured a graded sequence on a single dive — Anderson's field notes run from live corals and survivors through dying Acropora to dead Seriatopora hystrix and dead corals, documenting bleaching mid-collapse on one reef in one day. Published cover was 25% with 50% of coral tissue bleached; a nearby Reef Check station at essentially the same spot has averaged 36% hard coral across seven survey years (14 surveys) since 2010.
شعاب منزل نكاري الجنوبية، أول محطة في جولة المسح المصرية في سبتمبر 2024، التقطت تسلسلًا متدرجًا في غطسة واحدة - تتدرج ملاحظات أندرسون الميدانية من مرجان حي وناجين إلى Acropora محتضرة ثم Seriatopora hystrix ميتة ومرجان ميت، موثقةً الابيضاض في منتصف الانهيار على شعاب واحدة في يوم واحد. وبلغت التغطية المنشورة 25% مع ابيضاض 50% من نسيج المرجان؛ وقد بلغ متوسط محطة Reef Check قريبة في الموقع نفسه تقريبًا 36% من المرجان الصلب عبر سبع سنوات من المسوح (14 مسحًا) منذ 2010.
ترجمة هذا الملخص بالذكاء الاصطناعي؛ النص الإنجليزي هو المعتمد.
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Note: NOAA's regional station series averages 1.6°C warmer than the satellite pixel nearest this site (1.1 km away), which is used here instead.Eleven independent survey stations 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.
4 of the 20 photographs on this page are shown beside the text that discusses them under "Site description" below.
Site description
Setting
The southern arm of the Marsa Nakari house reef, and the first dive of the September 2024 Egypt leg with Red Sea Diving Safari.
General benthic features
Coral pinnacles and towers rise from a sand slope, with low bommies and open sand between them (e.g., Image 1, Image 3).
The colonies are knobby and encrusting Porites, olive and yellow-green Goniastrea/Favites heads, corymbose and staghorn Acropora stands, fine-branched Seriatopora hystrix, and Pocillopora (e.g., Image 2, Image 4).
Coral cover
- Reference: Mayfield (2025)
- Data file: (Mayfield, 2025-appendix A)
- CoralNet submission package (accession #5546)
- 25% ± 17% SD across 102 photographs.
Stressors
The site record reports 50% of coral tissue bleached at about 25.5°C-weeks DHW on the survey date (20 September 2024; NOAA Coral Reef Watch, Egypt virtual station), and adds a standing note for the Egypt leg: nearly all corals at these sites showed some degree of bleaching. What makes this dive worth reading closely is not the reef but the sequence Anderson photographed on it. Anderson's field notes on these frames run from live corals and resilient Acropora survivors through dying Acropora, Pocillopora, and Porites to mostly dead and dead Acropora, dead Seriatopora hystrix, and dead corals — a graded series from healthy through dying to dead, on one reef on one day.
Comparisons with other data
The site record also carries an external cross-reference: Reef Check's Marsa Nakari South station sits 0.10 km away and reports a mean of 36% hard coral across seven survey years (2010–2025; 14 surveys). The two are reported side by side and deliberately not averaged — different methods (CRD photographic point count vs Reef Check point-intercept transect), and at 0.10 km they are almost certainly the same reef.
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) | 25.1 | |
| In-house DINOv3 | 46.1 | n = 30 |
| CoralSCOP unedited | 25.9 | n = 119 |
| CoralSCOP edited | 28.0 | n = 107 |
| Claude (edited photos) | 23.9 | n = 103 · SE 1.7 |
| Reef Check 2025 (same site, mean of 2 same-day surveys) | 29.1 |
The four computer-vision methods disagree by 22.2 pp (23.9–46.1%) and read on both sides of the published point count (25.1%); 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).
See a more detailed, stand-alone version of this table.
Independent surveys nearby
| Agency / program | Year(s) | Stations / distance | Link |
|---|---|---|---|
| MERMAID project “Egyptian Red Sea Initiative - Egypt” | 2026 | 2 stations, 0.37–2.93 km | Records ↓ |
| Reef Check | 2003–2025 | 9 stations, 0.10–4.61 km | Records ↓ |
Coral Reef DiagnosticsYear-average (illustrative only, programs differ)Within 5 km, 11 independent survey stations recorded hard coral cover in 52 surveys between 2003 and 2026. Of the 8 stations surveyed in more than one year, 6 declined (by 2.0–14 points) and 2 increased (by 4.0–5.0 points) between their first and latest surveys. Two stations share the longest span (2010–2025); one, Marsa Nakari South (Reef Check, 0.10 km away), went from 37% in 2010 (mean of 2 surveys) to 29% in 2025 (mean of 2 surveys). Since 2021, station-year means average 44% (range 27–58%; n = 9 station-years from 16 surveys). This site's own estimate (25%) sits 2 points below the recent range of station-year means up to 2 km away (27–58%); the methods differ, so the comparison is context, not a like-for-like test.
Collected by other programs using different methods (Reef Check uses point-intercept transects; MERMAID is a data platform: each MERMAID row names the organization that did the survey, and its method is in the row's hover text), 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.
Show all 52 independent surveys
| Agency | Site / location | Date | Hard coral cover (%) | Distance | Link |
|---|---|---|---|---|---|
| Reef Check | Samaka Mogeha (North Marsa Nakari) | 2003–2005 | 43–49% (range of yearly means; 3 surveys) | 1.18 km | — |
| Reef Check | Checkpoint | 2003–2013 | 22–43% (3 surveys) | 3.63 km | — |
| Reef Check | Marsa Tondoba/3 Sisters | 2005–2012 | 39–61% (3 surveys) | 2.29 km | — |
| Reef Check | Gotta Nakari | 2005–2006 | 9.4–23% (range of yearly means; 3 surveys) | 2.70 km | — |
| Reef Check | Marsa Nakari South | 2010–2025 | 29–40% (range of yearly means; 14 surveys) | 0.10 km | — |
| Reef Check | Marsa Nakari North | 2010–2025 | 27–47% (range of yearly means; 13 surveys) | 0.22 km | — |
| Reef Check | Marsa Um Tondoba- 3 Sisters | 2014 | 52% | 4.61 km | — |
| Reef Check | Shaab Nakari, north-east side | 2017–2024 | 51–59% (range of yearly means; 6 surveys) | 2.88 km | — |
| Reef Check | Dream Lagoon Marsa Alam | 2022–2024 | 53–58% (range of yearly means; 4 surveys) | 1.55 km | — |
| MERMAID project “Egyptian Red Sea Initiative - Egypt” | House Reef Marsa Nakarii | 2026 | 41% | 0.37 km | MERMAID |
| MERMAID project “Egyptian Red Sea Initiative - Egypt” | Gotta Nekarii | 2026 | 54% | 2.93 km | MERMAID |
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.