Indonesia - Banda Islands: Goat Hall (Pulau Ai)

Setting

Goat Hall lies on the northeast shoulder of Pulau Ai, in the Banda Islands of Maluku, and Anderson dived it once, on the afternoon of 27 April 2018 — in at 13:04, 61 minutes, 14.0 m maximum, 8.53 m average, 29.44°C. The dive begins deep on a near-vertical wall and works steadily up onto a shallow crest, so the profile reads cleanly through the sequence.

General benthic features

The wall and drop-off shoulder (39 frames) is a steep-to-vertical face crusted in pink and mauve coralline algae and worked over by filter feeders: brown barrel sponges standing off the wall, black-coral bushes, and cream Sarcophyton toadstools (e.g., Image 3).

3

Stony coral here is patchy and dominated by two forms — mustard-yellow and golden-orange ruffled foliose plating consistent with Turbinaria, and large tan domes with even, regularly spaced corallites consistent with Diploastrea and massive Porites (e.g., Image 1, Image 2).

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Bright green Nephthea- and Sinularia-type soft corals, cream branching Acropora, and pink knobby pocilloporids fill the gaps. The upper wall and mixed slope (48 frames) is the genus-rich middle of the dive and the most varied ground on it: corymbose and branching Acropora in salmon-pink, cream, gold, and bright green; thick-fingered columnar Porites of the P. cylindrica/rus habit; maroon and purple foliose plating (Montipora/Echinopora-type); meandroid Platygyra- and Lobophyllia-type brains; encrusting Montipora sheets in yellow-green; free-living fungiids; and a large salmon-and-red sea fan consistent with Melithaea standing off the lip (e.g., Image 4).

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The crest and branching pavement (44 frames) is where the coral actually is. Fine-branched and corymbose Acropora, Seriatopora-type thickets, and golden Millepora-type hydrocoral form mounded, near-continuous carpets that run to the limit of visibility in four frames, with columnar Porites stands and pale lavender plating threaded through them (e.g., Image 5).

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A Sarcophyton terrace follows (7 frames), and it is one of the striking sights of the dive: hundreds of golden-tan, deeply convoluted toadstool leather corals packed wall to wall over the reef top, with stony colonies reduced to emergents inside them.

Coral cover

Coral cover: 37% — a blind Claude computer-vision point count of 144 of Anderson's edited photographs (20 points per photo; water, fish, and obstructions excluded). Other computer-vision methods are listed in the method table. Anderson is still comparing computer-vision models, and these figures will be updated as the methods improve.

Stressors

Condition was good and there was no bleaching event here: no crown-of-thorns, no disease lesion, and no Drupella scarring was seen in any of the 146 frames, and the black spiny mass beneath one branching colony resolves on close crop to feather-star arms and urchin spines, not Acanthaster. Two observations are worth recording and both are hedged. One frame shows a large massive dome, consistent with Astreopora or Porites, carrying a sharply bounded patch of denuded skeleton across perhaps a fifth of its upper surface; the exposed skeleton is already fouled gray-green with turf and a green Acropora has grown against its margin, so this reads as older partial mortality rather than recent bleaching. Two frames show a large helmet-shaped dome that is uniformly pale lavender-white and conspicuously paler than every colony around it; on close crop its polyps are intact and each corallite is discretely pigmented gray-violet, with no exposed skeleton and no tissue-loss margin, so this is most consistent with a blue chromoprotein color morph rather than bleaching — logged, not scored.

Fish and other fauna

Feather stars in vivid yellow-green and in black perch on the framework throughout. A hawksbill turtle sequence and shallow crest close the dive (12 frames), the turtle photographed four times among staghorn and corymbose Acropora, with a 1.5 m tabulate Acropora table in one frame and sergeant majors, butterflyfish, and anemonefish over the top. Fauna: the hawksbill, fusilier and anthias clouds, chromis, sergeant majors, Moorish idols, bannerfish, butterflyfish, anemonefish, feather stars in yellow-green and black, Diadema-type urchins, and barrel sponges.

Comparisons with other data

No independent survey was made at this exact site; the nearest ones are listed in the table below.

Dive record

It was his second dive of that day, after Shark Point on the same island, and it produced 146 frames, every one of which was reviewed.

Other notes

Two closing frames are open blue water.