Alor - The Arch

Setting

Alor, The Arch (West Ternate Island) — a wall/drop-off dive with dense, structurally varied coral cover throughout the sampled frames (e.g., Image 3, Image 29).

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Visibility ranged from a hazy blue mid-water background on the wall to clear, sunlit close-range framing in the shallows; no wreck, mooring, tag, or transect gear appeared in any reviewed frame.

General benthic features

The wall face and ledges carry large massive boulder corals (consistent with Porites), several capped by mushroom-shaped overhangs that create shaded arch-like recesses even where the site's namesake arch is not itself in frame, and a very large meandroid brain coral (consistent with Platygyra or a related merulinid) more than a meter across (e.g., Image 11, Image 36, Image 37, Image 44).

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Foliose/plate corals (Montipora or Pachyseris-type) form shelf-like ledges in several frames, often purple-pink or pale gray in tone — natural pigmentation and coralline-algae staining rather than bleaching (e.g., Image 7, Image 19, Image 43).

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Cauliflower Pocillopora clumps in gray-purple tones and tabular Acropora plates recur through the mid-depth sections (e.g., Image 21, Image 23).

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The shallower part of the dive is dominated by extensive dense staghorn/cauliflower Acropora thickets forming a near-continuous low canopy, several frames lit by strong sunbeams filtering down from the surface; one thicket includes a cluster of pale-tipped branches that reads as normal pale growing tips against otherwise healthy brown tissue rather than bleaching, called out here rather than assumed either way (e.g., Image 4, Image 15, Image 25, Image 41, Image 45).

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Crinoids (feather stars) perch on several coral heads, and red-orange encrusting sponge crusts and small dark ball sponges occupy shaded crevices between colonies (e.g., Image 49).

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Coral cover

Coral cover: 23% — a blind Claude computer-vision point count of 155 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 crown-of-thorns predation, disease, or widespread bleaching was seen in the sample.

Fish and other fauna

Reef fish include schooling fusiliers and small planktivores in blue water off the wall, damselfish and anthias among the branching thickets, and a pair of butterflyfish over one Acropora patch (e.g., Image 51).

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Comparisons with other data

Also on record for this site: A steep wall and open-water drop-off combined with shallower mixed coral habitat (e.g., Image 16, Image 50).

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Sand and exposed framework interrupted living cover; overhangs and strong light transitions carry the arch-and-wall character even where the arch itself is not in frame (e.g., Image 9, Image 14, Image 53).

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Other notes

Divers are visible at a distance in two frames but are not the subject (e.g., Image 13, Image 54).

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