Alor - Clown Valley
Part of the regional summary: Indonesia - Alor
More info
East Nusa Tenggara (NOAA CRW virtual station) · Lesser Sunda ecoregion mean=6.9°C-heating weeks Alor and the Pantar Strait sit in a zone of exceptionally strong upwelling, which holds these reefs several degrees cooler than NOAA’s satellite-derived figures imply. Read the heat-stress numbers here as a regional-scale indication, not as this reef’s own temperature history.An Alor slope that grades from encrusted rock and rubble near the entry to extensive, wall-to-wall staghorn and digitate Acropora thickets, with a low canopy of plating corals in between. Anthias and a school of unicornfish hang over the reef, and no bleaching or disease was visible.
Lereng Alor yang berangsur berubah dari batuan dan pecahan karang berkerak di dekat titik masuk menjadi rumpun Acropora bercabang dan berjari yang luas dan menyambung dari tepi ke tepi, dengan kanopi rendah karang lembaran di antaranya. Anthias dan segerombolan ikan unicorn melayang di atas terumbu, dan tidak terlihat pemutihan maupun penyakit.
Terjemahan ringkasan ini oleh AI; versi bahasa Inggris yang berlaku.
One independent survey station shown with the program’s logo — click one to see how far it is from this site.
Five other CRD dive sites within 5 km shown in orange — click a marker to open its page.
15 of these 50 photographs are shown beside the text that discusses them under "Site description" below.
Site description
Setting
A reef slope with a strong gradient from encrusted rock and rubble near the entry to extensive, dense branching-coral thickets further along. Visibility is good throughout with strong ambient light (e.g., Image 2).
General benthic features
Early frames show a mixed substrate of purple/maroon encrusting sponge or coralline patches over rubble and dead coral fragments, with a low mound of small-polyp branching coral (gray-green, cf. Seriatopora/Stylophora) at the margin (e.g., Image 3).
Mid-dive frames are dominated by foliose/cup-shaped coral colonies with pale rims (cf. Pachyseris/Echinopora) forming an almost continuous low canopy interspersed with red and maroon foliose algae (cf. Halymenia), a heart-shaped salmon-pink encrusting sponge, and scattered massive brain/faviid coral (e.g., Image 14, Image 17, Image 42).
A striking green encrusting/plating colony (possibly a stressed or naturally pigmented Montipora) sits beside gray encrusting sponge and red algae, with a diver's exhaust bubbles visible in the background (e.g., Image 6, Image 19).
Multiple wide frames further into the dive show dense, low-relief staghorn/digitate Acropora-type thickets stretching wall-to-wall across the frame, hosting anthias and small reef fish, with massive Porites boulders and brain corals as occasional structural breaks; two divers are visible swimming over one such thicket (e.g., Image 5, Image 22, Image 48).
Coral cover
Coral cover: 41% — a blind Claude computer-vision point count of 209 of Anderson's unedited photographs (20 points per photo; water, fish, and obstructions excluded). Other computer-vision methods are listed in the method table.
Stressors
No bleaching or disease is visible on any photographed coral; all colonies show normal pigmentation (browns, grays, greens, and the one notably green plating colony). No crown-of-thorns starfish (COTS) or other corallivores evident.
Fish and other fauna
A mid-water frame records a school of unicornfish/surgeonfish silhouetted in blue water above the reef (e.g., Image 44).
Comparisons with other data
Also on record for this site: A broad slope with pronounced variation in coral cover. Apparently shallower sections later in the dive supported dense branching thickets that greatly increased structural complexity, separated elsewhere by rubble, hardground, and older dead framework (e.g., Image 46).
Host anemones, leather and other soft corals, sponges, crinoids, and red encrusting growth were frequent, and anthias, chromis, other damselfishes, butterflyfishes, and surgeonfishes occupied the slope (e.g., Image 7, Image 26, Image 47).
The sequence includes a sea turtle, probably a green turtle (Chelonia mydas).
Other notes
No man-made objects beyond diver gear appear in this sample.
CV model comparison
More info
DINOv3 and CoralSCOP were run on the same photos and are listed for comparison. Coralscapes v2 and v1 were also run but are not shown: Anderson does not consider Coralscapes reliable for these photos. No diver transect exists for this trip, so agreement between the rows is not accuracy, and as of September 2026 no computer-vision method estimates coral cover accurately on new images; treat every row as indicative.| Method | Hard-coral cover (%) |
|---|---|
| In-house DINOv3 | 31.6 |
| CoralSCOP unedited | 22.4 |
| Claude | 41.0 |
Independent surveys nearby
Within 5 km, 1 independent survey station recorded hard coral cover in 2014. The most recent nearby survey is from 2014, so these values predate recent heat stress. This site's own estimate (41%) sits 33.0 points above the range of these surveys (8.0%); the methods differ, so the comparison is context, not a like-for-like test.
Collected by other programs using different methods, so these are context for the figures above, not a like-for-like comparison. Where a station was surveyed more than once the range is shown. Station names are not dive-site names.
| Agency | Site / location | Date | Hard coral cover (%) | Distance | Link |
|---|---|---|---|---|---|
| WWF-US / WWF-Indonesia | 5002 | 2014 | 8.0% (4 surveys) | 0.75 km | Amkieltiela, Abdillah T, Amkieltiela A, Andradi-Brown D, Lazuardi E. 2015. MBD 2014 & 2015. MERMAID |
Data & links
All images from Coral Reef Diagnostics. Data are from Coral Reef Diagnostics and the organizations named in the data-sources table above.
© Coral Reef Diagnostics.