Maldives - Dhigga Thila
Part of the regional summaries: Maldives - Central (Male Atolls / Ari / Vaavu) and Maldives
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Maldives (NOAA CRW virtual station)A soft-coral-draped pinnacle where every ledge drips with salmon, scarlet, and gold colonies in the current, though its crown bears algae-covered table-coral skeletons and fresh crown-of-thorns damage.
ސޮފްޓް ކޯރަލުން ނިވާވެފައިވާ ތިލައެކެވެ. އޮޔާގެ ތެރޭގައި ކޮންމެ ފަރުދަށެއްގައި ސާމަން، ރަތް، އަދި ރަން ކުލައިގެ ކޮލޯނީތައް އެލުވިފައި ހުރެއެވެ. ނަމަވެސް ތިލައިގެ މަތީގައި ކަނޑުވިނައިން ނިވާވެފައިވާ ޓޭބަލް ހިރިގާގެ ކަށިތަކާއި، crown-of-thorns ގެ އާ ގެއްލުން ހުރެއެވެ.
AI translation of this summary; the English is authoritative. (low confidence)
Two independent survey stations shown with the program’s logo — click one to see how far it is from this site.
13 of the 23 photographs on this page are shown beside the text that discusses them under "Site description" below.
Site description
General benthic features
A submerged pinnacle dressed for the occasion: every ledge and cave ceiling drips with soft coral in salmon, scarlet, orange, and gold, the fleshy colonies inflated in the afternoon current like flowering trees (e.g., Image 5, Image 13, Image 17).
A great leather coral spreads its rippled crown among them (e.g., Image 15), a Euphyllia colony (Anderson's ID) sits nearby (e.g., Image 2), a lattice sea fan opens against the blue (e.g., Image 24), and clouds of orange anthias hover over cauliflower-coral thickets (e.g., Image 19).
Coral cover
- Reference: Claude CV point count (this site's photos)
- Coral cover: 8.4% — a blind Claude computer-vision point count of 25 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
On this dive (24 May 2017), Anderson's field sheet records ten crown-of-thorns starfish (COTS) seen, and divers from Coral Reef CPR and Carpe Diem Maldives removed all ten. Up on the pinnacle's crown lie fields of algae-covered table skeletons (e.g., Image 18, Image 20), but down the flanks, in soft-coral country, this thila is pure color (e.g., Image 10).
One frame, in which Anderson recorded crown-of-thorns damage, shows three cauliflower-shaped branching colonies entirely stark white, branches crisp, beside a living brown colony of the same shape: fresh whole-colony mortality (e.g., Image 1).
Fish and other fauna
The strangest guests are the smallest: a translucent comb jelly pulsing past in open water like a living lantern (e.g., Image 22), and a ruffled maroon flatworm crawling along a white PVC pipe (e.g., Image 23).
Comparisons with other data
Reef Check surveyed this site (Dhigga Thila) in 2013, 0.08 km from the pin. Within 5 km, two Reef Check stations recorded station-year means of 14–62% hard coral cover between 2011 and 2017; the nearest, Reef Check at Dhigga Thila, 0.08 km away, read 29% in 2013.
CV model comparison
More info
A 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.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 | 21.6 | |
| CoralSCOP edited | 28.5 | |
| Claude (edited photos) | 8.4 | n = 25 · SE 3.5 |
| Reef Check 2013 (same site, mean of 3 same-day surveys) | 28.8 |
The two computer-vision methods agree within 6.9 pp (21.6–28.5%) and read 13.2–20.1 pp above Claude's blind point count (8.4%); 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
Coral Reef DiagnosticsWithin 5 km, 2 independent survey stations recorded hard coral cover in 7 surveys between 2011 and 2017. The one station surveyed in more than one year declined by 48 points between its first and latest surveys. The longest record, Digga Thilla (Reef Check, 0.22 km away), went from 62% in 2011 (mean of 2 surveys) to 14% in 2017 (mean of 2 surveys). The most recent nearby survey is from 2017, so these values predate recent heat stress. This site's own estimate (8.4%) sits 5.6 points below the range of these station-year means (14–62%), inside the 7-point method-noise floor (inconclusive); 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), 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.
| Agency | Site / location | Date | Hard coral cover (%) | Distance |
|---|---|---|---|---|
| Reef Check | Digga Thilla | 2011–2017 | 14–62% (range of yearly means; 4 surveys) | 0.22 km |
| Reef Check | Dhigga Thila | 2013 | 29%, mean of 3 surveys (5 m, 7 m, and 8 m) | 0.08 km |
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.