Coral Reef Diagnostics

Maldives - Fesdhoo wreck

Reef Check Foundation
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Part of the regional summaries: Maldives - Central (Male Atolls / Ari / Vaavu) and Maldives

05
Coral Health Index: TBD
Photo: Anderson Mayfield/Coral Reef Diagnostics
Country
Maldives
Survey date(s)
2017-05-25
Coordinates
3.9995, 72.7861
Coral cover
2.1%
Claude computer vision (20 edited photos) · other methods below · median 0.0%
Observations
shipwreckcrown-of-thorns
Heat stress
Most recent heat load record
30.1°C0.0°C-weeks
26 Oct 2026 · Bleaching Watch
5-year thermal stress load
5-year mean max. degree heating weeks (DHW)
2.2°C-weeksi
2021–2025
NOAA Coral Reef Watch — Maldives virtual station
i 5-year mean max. DHW is the mean of the annual maximum DHWs over the five complete years named above, not conditions today.
More infoMaldives (NOAA CRW virtual station)
Photographs
32
Site summary
Read this summary in:

A thoroughly feral wreck, its structure grown over with sponges, hydroids, and a doorway-sized sea fan, its hold filled with a single shifting mass of glassy sweepers and garden eels swaying on the sand nearby.

Max. depth dived
27.4 m
sample-sheet maximum
Sea surface temp. (satellite)
29.6°C
satellite sea surface temperature (SST) on the survey date (NOAA Coral Reef Watch, Maldives), not an in-water reading; it is the warmest-pixel (90th percentile) reading in the station area and can run 1–1.5°C above the reef

Four independent survey stations shown with the program’s logo — click one to see how far it is from this site.

16 of the 32 photographs on this page are shown beside the text that discusses them under "Site description" below.

1369151617181921262728303132

Photo credit & attribution

Site description

Setting

A small sunken ship gone thoroughly feral. The deeper frames show the wreck in gloom (e.g., Image 25).

25Image 25

General benthic features

Its masts and bollards have swelled into shaggy pillars of sponge and hydroid, a tan sea fan the size of a door spreads from the hull, and inside, the hold breathes with a single organism-like mass of glassy sweepers — thousands of translucent fish that part and reseal around a diver's light (e.g., Image 7, Image 11, Image 14, Image 22, Image 25, Image 2, Image 5, Image 8).

7Image 711Image 1114Image 1422Image 222Image 25Image 58Image 8

Orange cup corals and crimson sponges paint the sheltered steel, a gray table coral has claimed the bow like a flag, and out on the sand a colony of garden eels sways half-out of their burrows, sinking away as divers drift near (e.g., Image 12, Image 13, Image 4, Image 10, Image 23, Image 24).

12Image 1213Image 134Image 410Image 1023Image 2324Image 24

Look for the giant clam's spotted mantle among the coralline-pink rubble, and the long black spines of an urchin tucked into the wreckage (e.g., Image 20).

20Image 20

Coral cover

Stressors

On this dive (25 May 2017), Anderson's field sheet records nine crown-of-thorns starfish (COTS) seen, and all nine were collected; a crown-of-thorns starfish appears in the photographs from this dive (e.g., Image 29).

29Image 29

Comparisons with other data

We found no other surveys at this site as of 2026. Within 5 km, four independent stations recorded station-year means of 1.9–44% hard coral cover between 2011 and 2025; the nearest, Montefalcone et al. (2020) at Fesdu Wreck, 1.25 km away, read 21% in 2016.

CV model comparison

Mean 2.1%, median 0.0% across 20 photos.
More infoA few colony-focused photos raise the mean; the median is the typical photo. 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.
Headline: Claude computer vision, a blind point count of this site's own photographs.
More infoOther rows are for comparison only and are never averaged. No diver transect exists for these photos, so agreement between rows is not accuracy.
MethodHard coral cover (%)Photos (n) ± SE
In-house DINOv315.1
CoralSCOP edited13.8
Claude (edited photos)2.1n = 20 · SE 2.1

The two computer-vision methods agree within 1.3 pp (13.8–15.1%) and read 11.7–13.0 pp above Claude's blind point count (2.1%); 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

Data availability near this site
Agency / programYear(s)Stations / distanceLink
Montefalcone et al. (2020)20161 station, 1.25 kmRecords ↓
Reef Check2011–20252 stations, 2.73–3.65 kmRecords ↓
XL Catlin Seaview Survey2015–20171 station, 2.94 kmRecords ↓
Hard coral cover over time — this site and every independent station within 5 km. Programs are shown separately because they use different methods at different stations; the lines are not one comparable series.
0%12%24%36%48%201120182025Reef Check 2011: 44%Reef Check 2013: 44%Reef Check 2015: 38%Reef Check 2016: 5.8%Reef Check 2017: 1.9%Reef Check 2018: 1.9%Reef Check 2023: 25%Reef Check 2025: 40%XL Catlin Seaview Survey 2015: 14%XL Catlin Seaview Survey 2017: 8.1%Montefalcone et al. (2020) 2016: 21%Coral Reef Diagnostics 2017: 2.1%Year-averaged across all programs: illustrative only; the programs differ in stations and method, so no trend is claimed (8 years)
Reef Check XL Catlin Seaview Survey Montefalcone et al. (2020) Coral Reef DiagnosticsYear-average (illustrative only, programs differ)

Within 5 km, 4 independent survey stations recorded hard coral cover in 22 records between 2011 and 2025. Of the 3 stations surveyed in more than one year, 2 were scored by divers or by people annotating photographs: 2 declined (by 4.0–42 points) between their 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, Kudafalhu (Reef Check, 2.73 km away), went from 44% in 2013 (mean of 3 surveys) to 40% in 2025 (mean of 2 surveys). Since 2021, station-year means average 33% (range 25–40%; n = 2 station-years from 4 records). This site's own estimate (2.1%) sits 18.9 points below the one survey station up to 2 km away (21%); 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.

Independent survey data near this site
AgencySite / locationDateHard coral cover (%)DistanceLink
Reef CheckKudafalu2011–20171.9–44% (range of yearly means; 7 surveys)3.65 km—
Reef CheckKudafalhu2013–20251.9–44% (range of yearly means; 12 surveys)2.73 km—
XL Catlin Seaview Surveytransect 370082015–20178.1–14% (2 surveys)2.94 kmdoi:10.14264/uql.2019.930
Montefalcone et al. (2020)Fesdu Wreck201621%1.25 kmdoi:10.3389/fmars.2020.00587

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

  1. 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
  2. Gonzalez-Rivero M, et al. (2019). Seaview Survey photo-quadrat and image classification dataset. The University of Queensland (UQ eSpace) data collection. DOI