Maldives - Dhigurah Arches (night dive)

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

Photo: Anderson Mayfield/Coral Reef Diagnostics

Country

Maldives

Survey date(s)

2017-05-23

Coordinates

3.5401, 72.9153

Coral cover

not reported

Night dive.

Observations

None tagged; see Stressors below

Heat stress

Most recent heat load record

30.1°C 0.0°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 info

Maldives (NOAA CRW virtual station)

Photographs

8 shown on this page

Site summary

Read this summary in:

A torch-lit night dive where reef life goes nocturnal: cup corals bloom into luminous green polyp bouquets, a long-armed brittle star drapes a boulder coral, and an octopus slips across the sand at the edge of the light. No coral-cover figure is published — these are close macro shots, not a wide reefscape.

Max. depth dived

16.8 m

sample-sheet maximum

Sea surface temp. (satellite)

29.7°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

Bottom time

45 min

in at 18:43

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

6 of the 8 photographs on this page are shown beside the text that discusses them under "Site description" below.

Photo credit & attribution

Site description

Setting

A torch-lit dive after sunset, and the reef is unrecognizable from its daytime self.

General benthic features

Cup corals that spend daylight as drab knuckles have exploded into bouquets of luminous green polyps, every tentacle out and fishing in the dark (e.g., Image 1).

A cauliflower coral wears a fuzz of feeding polyps, a fleshy soft-coral tree stands fully inflated, and the walls glow pink with coralline algae under the beam (e.g., Image 2, Image 3).

Coral cover

Coral cover: not reported. This was a night dive, and its frames are close strobe-lit macro shots rather than wide reefscapes, so a photo-derived index would measure the lit subject and the framing rather than reef cover.

Stressors

One branching colony has white branch ends, recent mortality of unclear cause.

Fish and other fauna

The night shift is out: a long-armed brittle star drapes itself across a boulder coral like a starfish made of whips, and small wrasse doze wedged into crevices (e.g., Image 4, Image 5); an octopus also slinks across the sand at the edge of the light (e.g., Image 8).

Comparisons with other data

Reef Check surveyed a nearby station (Dhigurah Outreef), 1.83 km from the pin; we could not confirm that it is the same reef. Within 5 km, three Reef Check stations recorded station-year means of 19–63% hard coral cover between 2016 and 2023; the nearest, Reef Check at Dhigurah Outreef, 1.83 km away, read a mean of 32% in 2018.

Dive record

A 45-minute night dive, nearly all of it spent nose-to-reef.

Basis: 9 frames, all close strobe macro (Tubastraea polyps, soft coral, brittle star, octopus on sand); not one wide reefscape. A photo-derived index over frames like these measures the strobe-lit subject and the framing, not reef cover.

Independent surveys nearby

Hard coral cover over time — 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.

Reef CheckYear-average (no detectable trend)

Within 5 km, 3 independent survey stations recorded hard coral cover in 11 surveys between 2016 and 2023. Of the 2 stations surveyed in more than one year, 2 declined (by 12–44 points) between their first and latest surveys. The longest record, Dhigurah Wall (Reef Check, 2.70 km away), went from 39% in 2016 to 27% in 2023 (mean of 2 surveys). Since 2021, station-year means average 23% (range 19–27%; n = 2 station-years from 4 surveys).

Collected by other programs using different methods (Reef Check uses point-intercept transects), 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
Agency	Site / location	Date	Hard coral cover (%)	Distance
Reef Check	Coral Garden	2016–2022	19–63% (range of yearly means; 3 surveys)	2.67 km
Reef Check	Dhigurah Wall	2016–2023	22–39% (range of yearly means; 5 surveys)	2.70 km
Reef Check	Dhigurah Outreef	2018	32% (30–36%, 3 surveys)	1.83 km

Data & links

All images from Coral Reef Diagnostics. Data are from Coral Reef Diagnostics and the organizations named in the data sources above.