Egypt Red Sea - Marsa Nakari-North (Marsa Nakari)
Part of the regional summaries: Egypt and Red Sea
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Egypt (NOAA CRW virtual station)The northern arm of the Marsa Nakari house reef, sandy pavement with isolated colonies in the shallows dropping to a steep slope packed with branching, massive, and table corals, with a hunting lionfish. It was severely bleached in September 2024, with about 57% of coral tissue affected, at a published dive temperature of 31.5°C.
الذراع الشمالية لشعبة نزل مرسى نكاري، رصيف رملي تتناثر فيه مستعمرات منعزلة في المياه الضحلة ثم ينحدر إلى منحدر شديد مكتظ بالمرجانيات المتفرعة والكتلية والطاولية، مع سمكة أسد تصطاد. أصابه ابيضاض شديد في سبتمبر 2024 طال نحو 57% من الأنسجة المرجانية، عند درجة حرارة غوص منشورة بلغت 31.5°C.
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 (1.4 km away), which is used here instead.Seventeen 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 northern arm of the Marsa Nakari house reef, dived on the afternoon of 20 September 2024 with Red Sea Diving Safari.
General benthic features
The reef starts as sandy, coralline-crusted pavement with isolated colonies in the shallows, then drops down a steep slope carrying a dense, continuous coral framework of branching, massive, and table colonies — corymbose Acropora, pocilloporids, Porites, faviids, and encrusting Millepora-type fire coral (dead and overgrown with algae, which can make it look alive) (e.g., Image 1, Image 2, Image 3, Image 4) — with one large partly overgrown giant clam shell set into the pavement.
Coral cover
- Reference: Mayfield (2025)
- Data file: (Mayfield, 2025-appendix A)
- CoralNet submission package (accession #5546)
- 23% ± 14% SD across 195 photographs.
Stressors
The site record reports 57% 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). Anderson recorded the water temperature: two wrist shots of the dive computer read 32°C and then 31°C during the dive, averaging the published 31.5°C. Much of the pavement is old dead framework rather than recent loss, but scattered through it, in almost every wide-angle, are small stark-white colonies (e.g., Image 1, Image 3, Image 4). Anderson's field notes record the findings in detail: a badly bleached Acropora table, bleaching Porites, and dead Pocillopora, other pocilloporids, Porites, and fire coral.
Fish and other fauna
A lionfish (Pterois-type) hunts the patches.
Comparisons with other data
This site also carries an external cross-reference to Reef Check's Marsa Nakari North station 0.25 km away (a mean of 38% hard coral across seven survey years, 2010–2025; 13 surveys), reported side by side with the CRD figure and deliberately not averaged.
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, 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) | 23.3 | |
| CoralSCOP unedited | 28.4 | n = 205 |
| CoralSCOP edited | 29.0 | n = 188 |
| Claude (edited photos) | 22.7 | n = 172 · SE 1.1 |
The three computer-vision methods agree within 6.3 pp (22.7–29.0%) and read within 5.7 pp of the published point count (23.3%).
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, 0.11–2.79 km | Records ↓ |
| Reef Check | 2003–2025 | 15 stations, 0.25–4.78 km | Records ↓ |
Coral Reef DiagnosticsYear-average (illustrative only, programs differ)Within 5 km, 17 independent survey stations recorded hard coral cover in 72 surveys between 2003 and 2026. Of the 10 stations surveyed in more than one year, 6 declined (by 2.0–14 points) and 4 increased (by 4.0–13 points) between their first and latest surveys. Two stations share the longest span (2010–2025); one, Marsa Nakari North (Reef Check, 0.25 km away), went from 35% in 2010 (mean of 2 surveys) to 27% 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 (23%) sits 4 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 72 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) | 0.73 km | — |
| Reef Check | Checkpoint | 2003–2013 | 22–43% (3 surveys) | 3.19 km | — |
| Reef Check | Marsa Tondoba North | 2003–2014 | 39–53% (range of yearly means; 11 surveys) | 4.78 km | — |
| Reef Check | Marsa Tondoba/3 Sisters | 2005–2012 | 39–61% (3 surveys) | 1.88 km | — |
| Reef Check | Gotta Nakari | 2005–2006 | 9.4–23% (range of yearly means; 3 surveys) | 2.56 km | — |
| Reef Check | Tondoba Bay, outer reef North | 2005–2014 | 22–46% (range of yearly means; 5 surveys) | 4.59 km | — |
| Reef Check | Markas Ratz South | 2007 | 11% | 4.61 km | — |
| Reef Check | Marsa Nakari North | 2010–2025 | 27–47% (range of yearly means; 13 surveys) | 0.25 km | — |
| Reef Check | Marsa Nakari South | 2010–2025 | 29–40% (range of yearly means; 14 surveys) | 0.44 km | — |
| Reef Check | Marsa Um Tondoba North Entrance | 2013 | 14% | 4.69 km | — |
| Reef Check | Marsa Um Tondoba- 3 Sisters | 2014 | 52% | 4.15 km | — |
| Reef Check | Marsa Um Tondoba Lagoon | 2014 | 4.4% | 4.78 km | — |
| Reef Check | Marsa Um Tondoba Fringing Reef North | 2014 | 6.3% | 4.78 km | — |
| Reef Check | Shaab Nakari, north-east side | 2017–2024 | 51–59% (range of yearly means; 6 surveys) | 2.77 km | — |
| Reef Check | Dream Lagoon Marsa Alam | 2022–2024 | 53–58% (range of yearly means; 4 surveys) | 1.93 km | — |
| MERMAID project “Egyptian Red Sea Initiative - Egypt” | House Reef Marsa Nakarii | 2026 | 41% | 0.11 km | MERMAID |
| MERMAID project “Egyptian Red Sea Initiative - Egypt” | Gotta Nekarii | 2026 | 54% | 2.79 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.