Maldives - Anantara Dhigu house reef
Part of the regional summaries: Maldives - Central (Male Atolls / Ari / Vaavu) and Maldives
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Maldives (NOAA CRW virtual station)Anantara Dhigu's house reef is carpeted in tabletop corals running to the edge of visibility, and a honeycomb moray swam free across the open reef. The January 2016 photos catch the reef just months before the 2016 El Niño bleaching, with a few small colonies already showing recent mortality.
Anantara Dhigu ގެ ހައުސް ރީފުގައި، ލޮލަށް ފެންނަ ހިސާބަށް ދެން ޓޭބަލް ހިރިގާ ކާޕެޓެއް ފަދައިން ފަތުރިފައި ހުރެއެވެ. އަދި honeycomb moray އެއް ހުޅުވިފައިވާ ފަރުމަތިން މިނިވަންކަމާއެކު ފަތާފައި ދިޔައެވެ. 2016 ގެ ޖަނަވަރީގެ ފޮޓޯތަކުގައި ފެންނަނީ 2016 ގެ El Niño ހިރިގާ ހުދުވުމުގެ މަސްތަކެއް ކުރިން ފަރު ހުރި ގޮތެވެ. އޭރުވެސް ބައެއް ކުދި ކޮލޯނީތަކުގައި އަލަށް މަރުވެފައިވާ ނިޝާނާ ފެނެމުން ދިޔައެވެ.
AI translation of this summary; the English is authoritative. (low confidence)
Five independent survey stations shown with the program’s logo — click one to see how far it is from this site.
Nine other CRD dive sites with their own pages within 5 km shown in orange — click a marker to open its page.
10 of the 25 photographs on this page are shown beside the text that discusses them under "Site description" below.
Site description
General benthic features
In January 2016, the top of this house reef held tabletop corals by the hundred, tiered like café parasols and running unbroken to the edge of visibility (e.g., Image 1, Image 24, Image 25).
Slip over the edge and the slope turns wilder — rubble and pink coralline crusts, ledges daubed with red sponge, orange anthias swirling mid-water, and a river of silvery fusiliers passing overhead (e.g., Image 3, Image 4).
Coral cover
- Reference: Claude CV point count (this site's photos)
- Coral cover: 22% — a blind Claude computer-vision point count of 44 of Anderson's edited photographs (20 points per photo; water, fish, and obstructions excluded). Other computer-vision methods are listed in the method table.
Stressors
Months later the 2016 El Niño would bleach these reefs catastrophically. A cushion star, an armless pentagonal sea star that feeds on coral, rests on the rubble in one frame (e.g., Image 10); no crown-of-thorns starfish appear in the photographs.
Several small branching colonies already carry white sections, recent mortality of unstated cause (e.g., Image 13).
Fish and other fauna
The dive belonged to a honeycomb moray: boldly patterned in giraffe-print black and white, it posed for portrait after portrait and then did something morays rarely do in daylight — slid fully out of its hole and swam free across the open reef (e.g., Image 6, Image 7, Image 22).
A spiny lobster's banded antennae gave away its hiding place under an overhang, and a sea cucumber sprawled across the coral.
Comparisons with other data
Migliaccio (2024) and Bin Mohamad & Migliaccio (2025) surveyed this site (Anantara reef system) after the 2024 bleaching. Within 5 km, five independent stations recorded station-year means of 5.5–76% hard coral cover between 2015 and 2025; the nearest, Montefalcone et al. 2026 at Kuda Giri Wreck, 1.21 km away, read 39–43% between 2024 and 2025.
CV model comparison
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Mean and median agree. No computer-vision method yet estimates coral cover accurately on new images, so treat this as indicative rather than a measurement; it is revised as the methods improve.More info
Other rows are for comparison only and are never averaged. No diver transect exists for these photos, so agreement between rows is not accuracy.| Method | Hard coral cover (%) | Photos (n) ± SE |
|---|---|---|
| In-house DINOv3 | 24.4 | |
| CoralSCOP edited | 37.6 | |
| Claude (edited photos) | 22.1 | n = 44 · SE 2.6 |
The two computer-vision methods disagree by 13.2 pp (24.4–37.6%) and read 2.3–15.5 pp above Claude's blind point count (22.1%); the headline is Claude's blind point count because no transect or manual count exists here.
See a more detailed, stand-alone version of this table.
Independent surveys nearby
| Agency / program | Year(s) | Stations / distance | Link |
|---|---|---|---|
| Montefalcone et al. (2020) | 2015 | 1 station, 1.21 km | Records ↓ |
| Montefalcone et al. 2026 | 2024–2025 | 1 station, 1.21 km | Records ↓ |
| Reef Check | 2022 | 1 station, 2.54 km | Records ↓ |
| XL Catlin Seaview Survey | 2015–2017 | 2 stations, 2.90–3.64 km | Records ↓ |
Coral Reef DiagnosticsYear-average (illustrative only, programs differ)Within 5 km, 5 independent survey stations recorded hard coral cover in 7 records between 2015 and 2025. Of the 2 stations surveyed in more than one year, 1 was scored by divers or by people annotating photographs: declined by 4.0 points between its first and latest surveys. The other 1 was scored by automated image analysis: changed by 7 points or less, inside the 7-point method-noise floor (inconclusive). The longest record, transect 37035 (XL Catlin Seaview Survey, 2.90 km away), went from 7.1% in 2015 to 5.5% in 2017. Since 2021, station-year means average 34% (range 19–43%; n = 3 station-years from 3 records). This site's own estimate (22%) sits 17 points below the recent range of station-year means up to 2 km away (39–43%); 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; the XL Catlin Seaview Survey uses photo-transects with automated image annotation), 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. Values above 70% are marked “best patch”: surveys often target the densest coral on a reef, so these may overstate the site as a whole.
| Agency | Site / location | Date | Hard coral cover (%) | Distance | Link |
|---|---|---|---|---|---|
| Montefalcone et al. (2020) | Cocoa Corner | 2015 | 76% best patch | 1.21 km | doi:10.3389/fmars.2020.00587 |
| XL Catlin Seaview Survey | transect 37035 | 2015–2017 | 5.5–7.1% (2 surveys) | 2.90 km | doi:10.14264/uql.2019.930 |
| XL Catlin Seaview Survey | transect 37036 | 2015 | 38% | 3.64 km | doi:10.14264/uql.2019.930 |
| Reef Check | Gulhi Island Backreef | 2022 | 19% | 2.54 km | — |
| Montefalcone et al. 2026 | Kuda Giri Wreck | 2024–2025 | 39–43% (2 surveys) | 1.21 km | doi:10.1007/s00338-026-02850-x |
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
- Montefalcone M, Morri C, Bianchi CN (2020). Influence of Local Pressures on Maldivian Coral Reef Resilience Following Repeated Bleaching Events, and Recovery Perspectives. Frontiers in Marine Science 7:587. PDF
- Montefalcone M, Bianchi CN, Morri C, Ahmed H, Pancrazi I (2026). Outcomes of the fourth global coral bleaching (2023–2024) in the Maldives. Coral Reefs. DOI
- Migliaccio O (2024). Coral gardening in a changing climate: Rapid assessment of the 4th recorded bleaching event at the Anantara Lagoon and reef system, South Male Atoll, Maldives. Journal of Marine Studies 2:2101. DOI
- Bin Mohamad E, Migliaccio O (2025). Post-bleaching patterns of Acanthaster planci, Culcita schmideliana, and Drupella spp. in coral nurseries and natural reefs, Kaafu Atoll, Maldives. Journal of Marine Studies 2:2301. DOI
- Gonzalez-Rivero M, et al. (2019). Seaview Survey photo-quadrat and image classification dataset. The University of Queensland (UQ eSpace) data collection. DOI