Coral Reef Diagnostics

Alor - Goat Fence

Komodo Dragon Liveaboards — Naga Biru
⬇ Download this page as a report card
05
Coral Reef Diagnostics
Photo: Anderson Mayfield/Coral Reef Diagnostics
Country
Survey date(s)
2026-07-28
Coordinates
-8.2514, 124.4065
Approximate position.
Coral cover
11%
Claude computer vision (72 edited photos) · other methods below · median 7.1%
Observations
Heat stress
Most recent heat load record
26 Oct 2026 · No heat stress
5-year thermal stress load
5-year mean max. degree heating weeks (DHW)
2021–2025
NOAA Coral Reef Watch — East Nusa Tenggara 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 infoEast 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.
Photographs
115
50 shown on this page
Site summary
Read this summary in:

A steep, structurally complex Alor slope with three distinct zones: a shallow crest of staghorn and table Acropora with leather and pulsing soft corals, a very diverse mid slope of plating corals, massive Porites, brain corals, mushroom corals, and bubble coral, and a deeper slope where soft corals, red algae, and rubble take over.

Max. depth dived
20.3 m
dive-log maximum
Water temp. during survey
26–27°C
Water-temperature range logged on the dive (26-27°C, the author's dive notes).
Bottom time
60 min
in at 15:16
Dive setting
Sloping Reef · Beginner

Two other CRD dive sites with their own pages within 5 km shown in orange — click a marker to open its page.

This page shows 50 of the 115 photographs from this site, including every one the text cites.

2 of the 50 photographs on this page are shown beside the text that discusses them under "Site description" below.

123456789101112131415161718192022232425262728293031323334353637383940414244454647484950

Photo credit & attribution

Site description

Setting

Alor Kecil, Goat Fence — one dive on 28 July 2026, worked from roughly 20 m up a steep, structurally complex slope into water shallow enough that the surface ripples fill the top of the frame. Visibility was good but the light drops off quickly down the slope, and the deeper frames are blue-shifted enough that color-dependent identifications there are weaker.

General benthic features

The photographs sort into three clearly different zones. The shallow crest and upper slope is the coral-dense end: continuous beds of corymbose and tabulate Acropora in brown, purple, and gold, staghorn thickets with bright white growing tips, digitate Acropora and Pocillopora in lavender and blue, foliose Montipora and folded golden Turbinaria plates, and big toadstool leather corals (Sarcophyton) sitting among them. Carpets of pulsing Xenia/Anthelia soft coral cover whole stretches of the reef top, and orange anthias and damselfishes hang in clouds above them. The mid-slope is the most diverse ground in the set and reads as a mosaic rather than a monoculture: laminar and whorled plates consistent with Echinopora and Pachyseris speciosa (one colony a meter across in fine concentric ridges), massive Porites domes, large meandering brain corals consistent with Platygyra and Symphyllia, honeycomb Favites/Goniastrea, free-living Fungia mushroom corals scattered throughout, clusters of anchor/hammer coral (Euphyllia) with tan hammer-tipped tentacles, and at least three separate fully-inflated bubble corals (Plerogyra sinuosa) photographed close (e.g., Image 21, Image 43).

Sponges are present but secondary — black and olive barrel sponges with open oscula, red and orange encrusting crusts, and a few blue-gray branching forms. The deeper slope inverts the picture: soft corals (Dendronephthya, Sinularia, more Xenia), whip corals, and small gorgonian bushes take over, red fleshy macroalgae and turf mat large areas, magenta crustose coralline algae binds the rock, and broad bands of pale rubble and sand run between the colonies. Several deep frames are frankly low-cover — open pavement and broken branching rubble with widely spaced colonies — and a few show standing dead Acropora skeletons still in growth position.

Coral cover

Stressors

Condition is mixed: at least four colonies in the set are stark, fully bleached white (a foliose plate beside an intact green neighbor, a small colony in the shallow Xenia field, and two pale gray-white encrusting-plating colonies on the mid-slope). A handful of others carry small chalk-white patches of freshly exposed skeleton. Against that, the great majority of colonies photographed are fully pigmented and structurally intact; no crown-of-thorns, no bite scars, and no reef-wide bleaching front appear anywhere in the photographs.

Fish and other fauna

Invertebrate life is conspicuous: two giant clams (Tridacna) with speckled and green mantles, groups of magnificent anemones (Heteractis) with anemonefish, a carpet anemone, a blue Linckia sea star, black, white, gray, and vivid yellow-green feather stars on almost every high point, Diadema and other urchins, sea cucumbers, and a large solitary polyp with a deep red rim and pale oral disc consistent with Cynarina lacrymalis.

Comparisons with other data

We found no other surveys at this site as of 2026. If you would like to share yours, please email us.

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.

Other notes

Man-made content is limited to divers and their gear, one wrist dive computer, and one wrist watch photographed against a table Acropora; a small pale rectangular object on a sand ledge in one deep frame may be litter but cannot be resolved.

CV model comparison

Mean 11%, median 7.1% across 72 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 infoDINOv3 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.
MethodHard coral cover (%)Photos (n) ± SE
In-house DINOv319.3n = 72 · SE 0.9
CoralSCOP edited29.4n = 72 · SE 1.3
Claude (edited photos)10.7n = 72 · SE 1.3

The two computer-vision methods disagree by 10.1 pp (19.3–29.4%) and read 8.6–18.7 pp above Claude's blind point count (10.7%); the headline is Claude's blind point count because no transect or manual count exists here.

Data & links

All images from Coral Reef Diagnostics. Data are from Coral Reef Diagnostics.

© Coral Reef Diagnostics.

References

  1. 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