Indonesia - Halmahera: AM Point 2

General benthic features

The deep wall is dim and silt-dusted, a matrix of red crustose coralline algae carrying a heavy filter-feeder community: olive perforated tube/repent sponges, lavender encrusting sponges and ascidians, pink and red barrels, azooxanthellate Dendronephthya/Scleronephthya-type soft corals, white sea whips, lacy gorgonians, and crinoids (e.g., Image 10, Image 16, Image 31, Image 36, Image 37, Image 54).

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Hard coral is scattered there: Pachyseris-type plates, foliose Montipora, meandroid Platygyra/Leptoria brains, fungiids, and a Diploastrea-type dome (e.g., Image 1, Image 9, Image 11, Image 12, Image 14, Image 21, Image 40, Image 43).

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The mid slope has very high generic diversity plus an extensive shingled foliose plate field (Echinopora/Montipora-type) with big tabulate Acropora tables and a Tridacna (e.g., Image 3, Image 34).

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The upper slope starts as white sand and coralline-crusted rubble with almost no coral in some frames, then a vast lavender fine-branched thicket (consistent with digitate Montipora or Anacropora), gray Sarcophyton toadstools, leopard-patterned sea cucumbers, and mauve foliose plate fields threaded with red branching macroalgae (Galaxaura-type) with bannerfish (e.g., Image 17, Image 22, Image 49).

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Farther along it adds extensive mauve and salmon foliose Montipora plate fields at near-continuous cover, abundant green barrel ascidians, red gorgonians with polyps out, lavender tube sponges, and one broad broken-coral rubble plain with small recruits. The shallow reef top and crest is a near-continuous, structurally complex mixed-genus pavement (e.g., Image 4, Image 13).

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Shingled foliose plating in three distinct color morphs — salmon-pink, mauve-lavender, and pale gray-green (Echinopora-type and foliose Montipora) — forms meter-scale monospecific stands inside a matrix of white-tipped branching Acropora, Seriatopora/Pocillopora-type thickets, digitate and corymbose colonies, encrusting Montipora, and frequent free-living fungiids (e.g., Image 24).

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Deep-red branching macroalgae and red encrusting sponge thread through the framework (e.g., Image 28, Image 50), and one view of the crest is dominated by red crustose and foliose coralline rather than coral (e.g., Image 49).

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The dive then turns onto a stretch where octocorals, not stony coral, hold the ground: broad fields of gray-green and tan Sarcophyton/Sinularia toadstools carpet the upper slope, with stony colonies reduced to emergents within them (e.g., Image 30, Image 38).

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Large dark red-brown repent sponges sprawl meters across the framework, and massive red barrel sponges stand on the slope (e.g., Image 47).

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Individual set-pieces on this stretch: a pale tabulate Acropora table roughly 1.5 m across, with a small branching colony rooted in a gap at its center; a vivid salmon-pink meandroid brain (Lobophyllia/Symphyllia-type); and a single large elongate fungiid filling the frame. Farther on, the octocoral ground resolves into a near-monospecific soft-coral meadow rather than scattered colonies. In places tan and olive Sarcophyton/Sinularia toadstools carpet the entire visible slope to the horizon in an essentially unbroken sheet, with only narrow gutters of coralline-crusted rubble showing through; closer views of the same meadow show free-living fungiids and the occasional branching colony sitting as emergents inside the octocoral matrix (e.g., Image 18, Image 32, Image 38).

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Away from the meadow, patches hold a genuinely mixed, near-continuous assemblage: blue-gray and lavender digitate and branching Acropora, cream-yellow corymbose colonies, foliose plates, olive-yellow colonial ascidians, and Tridacna clams with white-and-green maze mantles. The dive then enters a fourth, shallow habitat — a sunlit reef flat and crest with the surface visible overhead, and an assemblage built on robust massive and columnar growth forms rather than plates or octocorals. Thick-fingered columnar Porites dominate, standing as raised stands and bommies, alongside large smooth massive Porites domes in maroon, purple-brown, and olive (e.g., Image 33).

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Tabulate Acropora tables recur across the flat, green ruffled columnar-foliose Pavona-type colonies form ridges, and a distinctive golden-brown ruffled hydrocoral consistent with Millepora recurs. Healthy staghorn and corymbose Acropora thickets close the sequence (e.g., Image 53).

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The shallow ground beyond the flat alternates sharply between near-continuous coral and near-bare substrate. At the high-cover end, a vast blue-gray and tan branching field runs to the horizon, a near-monospecific stand of overlapping corymbose Acropora fills the frame, and a steep face is carpeted in rounded encrusting Montipora-type plates with several Tridacna mantles set into it (e.g., Image 13). At the low-cover end, bare turfed boulders and pavement carry only scattered Pocillopora, an orange-tan meandroid brain, and a few small massives. Color standouts: a vivid violet branching Acropora, magenta Pocillopora, and a fleshy large-corallite colony consistent with Goniopora (e.g., Image 44).

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The highest-cover ground on the whole dive is a steep slope falling into deep blue, sheeted almost wall-to-wall in living coral. Two growth forms share it: carpets of fine-branching pale gray-green Acropora/Seriatopora, and vast fields of brown ruffled foliose plating consistent with Echinopora or Merulina, which in places form a continuous lettuce-like expanse meters across with orange anthias hanging over it (e.g., Image 7, Image 20, Image 23).

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Rounded encrusting Montipora discs tile the steeper faces, and a large smooth gray-blue plating colony and dark foliose rosettes punctuate the slope (e.g., Image 47). Free-living fungiids are conspicuously abundant on this slope, six to eight per frame in places — a far higher density than anywhere shallower. Farther along, near-total cover holds across a long stretch of slope, with yellow-green ruffled foliose fields and fine-branching Acropora carpets interlocking so completely that bare substrate is essentially absent in places (e.g., Image 27).

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Tabulate plates reappear, and a tan meandroid brain and a corymbose Acropora table sit side by side. At the end of this stretch a field of overlapping tabulate Acropora tables opens out with a diver and bubble trail overhead, a large smooth cream massive Porites dome and a pale meandroid brain anchoring the foreground. The outer wall and drop-off that follow are the structural high point of the site. The wall runs near-vertical into blue water and is sheeted continuously in coral from the lip downward, with divers giving scale (e.g., Image 2, Image 8, Image 19, Image 41).

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Gray-brown cabbage-like foliose rosettes dominate the upper wall, giving way downslope to extensive fields of large overlapping tabulate Acropora tables, stacked in tiers across tens of meters and individually approaching a meter or more (e.g., Image 6, Image 23, Image 24).

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This part of the wall ends on a vast near-monospecific staghorn Acropora thicket carpeting the slope with a diver silhouetted above it, with blue-tinted encrusting colonies threading through the branching. This outer-wall zone, not the shallow crest, is where the site's structural complexity peaks. The dive closes on the outer wall and reef top, and this is where AM Point 2 justifies the dive log's “amazing corals in the shallows.” Tabulate Acropora tables dominate: single plates near a meter across, tiered ranks descending the wall, and a rosette-like cluster of overlapping tables viewed from above (e.g., Image 26, Image 29).

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Branching-Acropora plains run unbroken to the horizon in lavender, pink, and bronze, with scattered fungiids, urchins, and a sea cucumber set into them (e.g., Image 25, Image 48).

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Large smooth massive Porites bommies punctuate the table fields, and brown ruffled foliose plating returns in quantity (e.g., Image 29, Image 46).

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One wide-angle frame sums up the site: ruffled foliose Echinopora fields in the foreground, rows of tabulate tables behind, massive Porites bommies to the right, and anthias over the whole scene (e.g., Image 5).

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Taken across the frames reviewed, AM Point 2 is a genuinely multi-habitat site — sponge-and-octocoral deep wall, shallow foliose crest, octocoral meadow, columnar-Porites flat, near-total-cover steep slope, and outer-wall table fields — and that, not measurement noise, is what produces the wide spread in cover.

Coral cover

• Reference: Claude CV point count (this site's photos)
• Coral cover: 40% — a blind Claude computer-vision point count of 223 of Anderson's unedited photographs (20 points per photo; water, fish, and obstructions excluded). Other computer-vision methods are listed in the method table.
• The wide spread (Claude: 40% ± 28 SD, range 0–100%) is a genuine multi-habitat signal, not noise: the sponge- and coralline-dominated deep wall and the bare sand/rubble patches sit at one end, the shallow plate-and-branching pavement at the other.
• The Sarcophyton/Sinularia soft-coral meadow is the single most extensive habitat on the dive and is almost certainly what pulls the site mean down relative to the shallow plate-and-branching crest, since soft coral does not count as hard-coral cover.
• Cover on the columnar-Porites reef flat is high and diversity is the broadest on the dive, but the flat is interrupted by substantial sand and broken-rubble aprons and by turf-covered dead framework — the same patchiness that drives the spread.

Stressors

On the octocoral stretch, extensive plains of broken branching-coral rubble, pink with crustose coralline and grading into open sand, carry only isolated survivors — a corymbose Acropora plate and a golden bushy hydroid/hydrocoral colony with yellow and black crinoids (e.g., Image 42).

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These rubble plains, together with nearby sand patches, sit at the low end of the dive's cover range and indicate past physical breakage on this part of the slope. On the shallow ground beyond the reef flat, a close view of dead branching rubble is diagnostic: it is almost completely smothered by a brown encrusting overgrowth (sponge, ascidian, or Lobophora-type alga — not resolvable at this scale), with only two small purple Acropora recruits surviving on it. Read together with the rubble plains and the dead apron fringing the large branching field nearby, this is consistent with old partial mortality of unknown cause on the shallow reef, now being colonized rather than recovering as coral. Even the highest-cover steep slope has a dead base: one stretch is a matrix of dead, turf-covered branching rubble carrying only scattered pale Acropora recruits, and a vast branching field there runs over a brown encrusting dead base, so the living veneer sits on a substantial dead framework. On the deep wall, one dark-green plate carries a sharp-edged, stark-white patch of bare skeleton that is recently dead; the cause is not stated (e.g., Image 12). No crown-of-thorns starfish (COTS) or other corallivores were evident.

Fish and other fauna

Lavender and purple tube sponges, green barrel ascidians, crinoids, and a brittle star recur throughout; chromis and anthias shoal over the reef top, with yellow butterflyfish and damsels. On the crest, Tridacna mantles are recurrent, several with the blue-and-green maze patterning (e.g., Image 45).

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Beside the soft-coral meadow a small orange sea star appears, and the golden bushy hydroid colony from the rubble plains turns up again hosting both a bright yellow and a black crinoid (e.g., Image 42). On the high-cover steep slope, Tridacna mantles, a golden feathery crinoid, bright green crinoids, and schooling anthias complete the scene.

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.

Other notes

Divers appear in frame for scale on the crest, across the octocoral ground, on the reef flat, and on the outer wall; near the end of the dive a snorkeler or freediver hangs over the reef and a diver's fin enters the frame. The anomaly of the dive lies on the steep slope: a flat pale rectangular slab with several small coral colonies established on its upper surface and block-like objects at its margins — the geometry is artificial rather than reef rock, and it reads as a deployed substrate or settlement module rather than natural framework. It is not identifiable from a single frame and is logged rather than interpreted.