Indonesia - Halmahera: Batu Mandi

General benthic features

A remote offshore sea mount worked in heavy current to 32.6 m at 25–26°C, stacking three quite different habitats — which is why cover is so unstable (Claude: 12% ± 13 SD over only 22 frames, spanning 0.0–53%). The deep base and terrace (9 of 24 frames) is a white sand-and-rubble plain over crustose-coralline pavement carrying widely spaced giant colonies and little between them: pale cream lobate Porites (e.g., Image 6, Image 15, Image 16, Image 18), a gray meandroid brain coral (Platygyra/Leptoria-type) free on open sand (e.g., Image 1), broad laminar plates consistent with Turbinaria or Echinophyllia (e.g., Image 2, Image 24, Image 29), and solitary fungiids.

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These are the near-zero frames. The rim walls (6 frames) drop straight into blue water and are plastered with pink and red crustose coralline algae, maroon, scarlet, yellow, orange, and violet sponges, gray didemnid ascidian clusters, and feather stars (e.g., Image 3, Image 19, Image 22); hard coral there is thin encrusting/plating Montipora-type plus tabulate Acropora cantilevered over the lip (e.g., Image 9).

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The summit is the site's signature: in 6 of 24 frames the current-swept crest is blanketed almost wall-to-wall in rust-brown to olive arborescent soft coral (Dendronephthya/Nephthea/Litophyton-type) over crimson encrusting sponge (e.g., Image 8, Image 20, Image 25), with pale blue-gray Porites domes rising through it (e.g., Image 21, Image 28); corymbose and staghorn Acropora thickets on the mid-flank supply the highest-cover frames (e.g., Image 4).

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Coral cover

• Reference: Claude CV point count (this site's photos)
• Coral cover: 12% — a blind Claude computer-vision point count of 22 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

Several massive Porites read pale cream in the deep, unstrobed light; no frame shows unambiguous bleaching (e.g., Image 6, Image 15, Image 16, Image 18). One brain coral carries two small reddish-brown patches of missing tissue; a healed injury fits as well as disease (e.g., Image 1).

Fish and other fauna

Two frames are pure blue water holding a dense fusilier/jack school (e.g., Image 26).

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Anderson's log records sharks, Napoleon wrasse, bumphead parrotfish, and stingrays on this dive; none of them is resolved in the stills.

Comparisons with other data

WCS Indonesia surveyed the Legoma (Laigoma) station in 2024 (Guraici MPA 2024; data via MERMAID), recording 19% hard coral cover. The pin was placed on that station because this dive's position is known only to the island, so the station is an island-area survey, not a survey of this dive site; station names are not dive-site names.

Other notes

Anderson's field note: “crazy currents on top of remote sea mount, sharks, Napoleons, bumphead parrotfish, stingrays”