Alor - Apuri Bay
Part of the regional summary: Indonesia - Alor
More info
East Nusa Tenggara (NOAA CRW virtual station) 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.Dense mixed coral gardens and low staghorn thickets on a current-influenced slope. Its centerpiece is a single massive coral head at least 2-3 m across that dwarfs a diver, with bamboo fish traps (bubu) sitting on the sand nearby.
Taman karang campuran yang rapat dan rumpun karang bercabang rendah pada lereng yang dipengaruhi arus. Pusat perhatiannya adalah satu koloni karang masif berukuran sedikitnya 2-3 m yang membuat penyelam tampak kecil, dengan bubu ikan dari bambu tergeletak di pasir di dekatnya.
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 with their own pages within 5 km shown in orange — click a marker to open its page.
These are unedited originals; edited versions will replace them.
This page shows 50 of the 211 photographs from this site, including every one cited by image number in the text; the frames the text describes as not shown are not among them.
20 of the 50 photographs on this page are shown beside the text that discusses them under "Site description" below.
Site description
Setting
A current-influenced slope whose coral cover ranged from exposed framework and rubble to dense mixed gardens (e.g., Image 15, Image 51, Image 52).
Visibility is good in most frames, with one frame showing localized turbidity/silt haze around a rock outcrop. The exceptional 17-24°C logged range is consistent with strong upwelling.
General benthic features
A reef with a very large massive coral boulder colony as its centerpiece: one frame shows a diver dwarfed beside a single lobed, brain-textured massive coral head at least 2-3 m across, its surface evenly pigmented apart from small pits and borings, and colonized at the base by encrusting purple zoanthids and a maroon foliose alga; bamboo fish traps (bubu) sit on the sand immediately behind it, tied to trap lines that run across the site (e.g., Image 25, Image 44).
A second wide frame at a different point on the reef shows more of these bamboo traps beside more coral (e.g., Image 13, Image 26).
Elsewhere the reef is a fine-grained mosaic of low mounding and plating colonies (gray-brown massive heads, pale plating corals with white growing edges, one vivid green plating colony) interspersed with red encrusting sponge/algae, a lilac soft coral, and open rubble, transitioning in other frames to dense low staghorn-type branching coral thickets over rubble (e.g., Image 5, Image 21, Image 22, Image 28, Image 49).
Recognizable groups included branching and tabular corals, bushy branching corals, foliose corals, massive corals, leafy and scroll-shaped plates, fungiids, and fleshy or brain-like merulinids (e.g., Image 1, Image 29).
Barrel sponges, gorgonians, crinoids, and leather corals completed the benthic mosaic, with anthias, chromis, butterflyfishes, and surgeonfishes above the reef (e.g., Image 11, Image 16, Image 53).
Coral cover
- Reference: Claude CV point count (this site's photos)
- Coral cover: 29% — a blind Claude computer-vision point count of 208 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 widespread bleaching apparent, though cover and condition varied markedly along the route. The photo review saw no bleaching of live tissue, and the giant massive coral head is evenly pigmented in the frame that shows it (e.g., Image 25), with no disease visible; however, a computer-vision point count called 0.3% of coral points bleached (3 of 208 photos). Fishing gear: at least five woven-bamboo fish traps (bubu) sit on the reef among live coral, and their heavy ropes and a blue line are strung over a large massive colony (e.g., Image 13, Image 25, Image 26, Image 44); a dark-red folded trap lies over rubble beside a branching colony (photo not shown). A few corals were recently dead, cause unclear: stark-white, polyp-free branches inside one branching colony (e.g., Image 55), and a white bare patch on a large brown plating colony that algae are beginning to colonize (photo not shown).
No crown-of-thorns starfish (COTS) or other corallivores were evident.
Fish and other fauna
A school of dozens of small silvery fish is visible mid-water off the reef edge in one frame (e.g., Image 3).
Comparisons with other data
We found no other surveys at this site as of 2026. Within 5 km, one independent station, WWF-US / WWF-Indonesia at station 5002, 0.63 km away, read 8.0% in 2014.
Regional context, not a survey of this site: Razak et al. (2026) found no significant trend in hard coral cover around Alor (a decline of 0.6% per year at 23 sites, surveyed by point-intercept transect at about 8–10 m in 2014, 2017, 2021, and 2023 by Yayasan WWF Indonesia); this is a trend for that location, not this site’s cover. Cover at those sites fell by 3% between the 2014 and 2017 surveys, which bracket 75 days of NOAA Bleaching Alert Level 1 from December 2016 to February 2017.
Dive record
Anderson's dive computer appears in one frame in watch mode, showing the time (12:15) and 18°C, near the cold end of the 17–24°C range in Anderson's dive log (e.g., Image 19).
Other notes
The bamboo fish traps and their lines are the clearest man-made objects in this sample.
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
DINOv3 and CoralSCOP were run on the same photos and are listed for comparison. No diver transect exists for this trip, so agreement between the rows is not accuracy, and no computer-vision method yet estimates coral cover accurately on new images; treat every row as indicative.| Method | Hard coral cover (%) | Photos (n) ± SE |
|---|---|---|
| In-house DINOv3 | 28.3 | n = 208 · SE 0.6 |
| CoralSCOP unedited | 20.2 | n = 208 · SE 0.9 |
| Claude | 28.7 | n = 208 · SE 1.4 |
The two computer-vision methods differ by 8.1 pp (20.2–28.3%) and read 0.4–8.5 pp below Claude's blind point count (28.7%); 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
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 (29%) sits 21.0 points above the one nearby survey station (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 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 | Link |
|---|---|---|---|---|---|
| WWF-US / WWF-Indonesia | 5002 | 2014 | 8.0% | 0.63 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 above.
© Coral Reef Diagnostics.
References
- Razak TB, Alisa CAG, Abrar M, Ardiwijaya R, Bachtiar I, Budaya RR, et al. (2026). Two decades of coral monitoring reveal thermal stress thresholds on Indonesian reefs. Biological Conservation 318:111781. DOI