Indonesia - Banda Islands: Batu Kapal

Setting

Batu Kapal — Indonesian for ship rock — is an isolated pinnacle in the channel northeast of Banda Neira, and the establishing topside frame shows exactly why it earned the name: a low, dark, flat-topped rock sitting alone on open water with the Banda mainland faint on the horizon.

General benthic features

The deep wall and descent (17 frames) is a steep, current-swept face and it is not a stony-coral habitat at all: the wall is sheeted in bright orange Dendronephthya soft coral, in dense bushes and drapes, over pink and mauve crustose coralline algae, encrusting sponges, black-coral bushes, and blue tunicates, with hard coral reduced to a few small massives and pocilloporid clumps. A brain coral and plate shoulder follows (15 frames) where stony coral takes over: a superb golden-tan meandroid dome close to a meter across, consistent with Platygyra or Symphyllia, a vivid yellow-green Pocillopora colony, tabulate Acropora tables standing off the lip, foliose Turbinaria in mustard-yellow, red barrel sponges, and further orange Dendronephthya. A Sarcophyton and Lobophytum terrace caps the pinnacle (9 frames) and is the single most extensive habitat on the dive: cream and tan toadstool leather corals with deeply convoluted margins carpet the reef top essentially wall to wall in four frames, with stony colonies reduced to emergents inside them. The reef-top pavement (21 frames) is the low-cover ground and it is genuinely low: broad plains of coralline-crusted rubble and turf-covered pavement carrying scattered colonies, interspersed with real high spots — large smooth massive Porites domes and pale plating discs, further meandroid brains, and one extensive near-continuous field of mauve foliose plating (e.g., Image 3).

3

The mixed crest and plating wall closes the dive (18 frames): corymbose and digitate Acropora, pink and magenta Pocillopora, massive Porites, and a dense golden-brown Millepora-type hydrocoral thicket with white-tipped branches that holds two large morays, then a final wall zone of large pale gray-tan laminar and foliose plating colonies (e.g., Image 5).

5

Batu Kapal is a small, exposed, current-swept pinnacle whose deep wall is soft coral and sponge, whose reef top is octocoral meadow, and whose pavement is old coralline rubble — a genuinely moderate hard coral habitat, unlike the continuous Acropora reefs at Pulau Ai.

Coral cover

Coral cover: 16% — a blind Claude computer-vision point count of 78 of Anderson's edited photographs (20 points per photo; water, fish, and obstructions excluded). Other computer-vision methods are listed in the method table. It is the lowest of the Banda dives, and the photographs largely support a moderate figure here. Anderson is still comparing computer-vision models, and these figures will be updated as the methods improve.

Stressors

Condition. No crown-of-thorns, no disease lesion, and no Drupella scarring was seen in any of the 81 frames, and there is no sign of a bleaching event. One earlier hedge is now resolved: the several large plates that looked chalky white on a frame shot into blue water at range are seen close in the next two frames to be living pale gray-tan foliose colonies whose margins carry a clean, thin, bright white growing rim. A crisp white growth margin on an otherwise pigmented plate is active accretion, not bleaching, and that call can now be closed. The one remaining hedge is a large pale cream-white massive dome distinctly paler than its neighbors, shot at range through hazy blue water where color cannot be trusted; it is logged, not scored. What the pinnacle does carry is a lot of long-dead framework: the rubble and turf pavement across eight frames is old, fully consolidated, and coralline-crusted, so it records historical loss rather than anything recent.

Fish and other fauna

Clouds of chromis, damsels, and fusiliers hang off the face in almost every frame, and a clown triggerfish (Balistoides conspicillum) works the wall across three consecutive frames (e.g., Image 2).

2

Fauna is the strength of this site. Two large morays were photographed, a honeycomb moray consistent with Gymnothorax favagineus tucked under a table Acropora and a gray speckle-headed moray consistent with Gymnothorax javanicus lying open-mouthed in the Millepora thicket. A banded sea krait (Laticauda colubrina) hunts across the pavement in two frames. Add the clown triggerfish, redtooth triggerfish, Pseudanthias, fusiliers, unicornfish, surgeonfish, pyramid butterflyfish, bannerfish, anemonefish, and the near-permanent planktivore cloud that the current feeds.

Comparisons with other data

How the number behaves here, and a disagreement worth Anderson's attention. Different station, different observers: a near-concurrent cross-check, not a repeat of this site.

Dive record

Anderson dived it on 28 April 2018, 09:51 to 10:46, 55 minutes, 14.9 m maximum and 10.06 m average, in 29.4°C water. It was a working dive — a buddy pair appears repeatedly running out a measuring tape and writing on a slate — and it produced 81 frames, every one of which was reviewed.