Indonesia - Halmahera: Tower Corner

Setting

A current-exposed corner dive on 11 August 2026 worked to 28.7 m at 25–26°C, with the reef getting steadily better the shallower it goes. Anderson's field note is unambiguous about where the dive peaked: "very strong currents at depth, used hook, amazing corals from 2–7 m."

General benthic features

The deep, scoured faces are the low end of that range: bare rock plastered in pink and red crustose coralline algae with blue, violet, and scarlet encrusting sponges, carrying only scattered thumbnail-sized cream coral recruits (e.g., Image 13, Image 28, Image 32, Image 48).

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The mid-slope (roughly 15–25 m) is a mixed garden — brown arborescent and leathery soft corals, gray and blue-gray massive Porites, laminar Turbinaria- and Echinophyllia-type plates set on white sand-and-rubble aprons, purple Sarcophyton and Sinularia leathers, gray sea fans and wire coral off the lip, and one broad whorled foliose colony (Turbinaria/Merulina-type) close to a meter across (e.g., Image 7, Image 10, Image 11, Image 14, Image 24, Image 26, Image 27, Image 29, Image 37, Image 46, Image 53).

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The 2–7 m crest is the site's signature and matches the field note exactly: near-continuous pink, mauve, and olive staghorn and corymbose Acropora thickets running frame to frame, with tabulate Acropora plates cantilevered over the drop-off, finger-like Porites stands, Pocillopora, Seriatopora, Platygyra brains, and shingled foliose plating packed in between (e.g., Image 1, Image 5, Image 6, Image 8, Image 9, Image 12, Image 16, Image 17, Image 18, Image 19, Image 20, Image 21, Image 31, Image 35, Image 36, Image 38, Image 39, Image 41, Image 42, Image 43, Image 50, Image 55).

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Coral cover

• Reference: Claude CV point count (this site's photos)
• Coral cover: 34% — a blind Claude computer-vision point count of 242 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

On the deep wall, two wire corals are white along their whole length: possible bleaching (one frame, Image 28). No hard coral colony was seen bleached, and no disease lesions or crown-of-thorns were seen in the 32 of 242 frames examined (a randomized subset). On the mid-slope, one brown massive colony carries many small white spots on its lobe tops, small spots of recent mortality, cause not stated (e.g., Image 37).

Fish and other fauna

Fish are dense throughout: clouds of anthias and chromis over every coral-covered surface, fusiliers off the wall, an anemonefish on the crest, and crinoids on the exposed rock (e.g., Image 3, Image 15).

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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.