Indonesia - Halmahera: Mugia

General benthic features

The reef itself, in the two frames that show it wide, is a bed of stacked, upward-cupped foliose plates — tiered shelving plate after plate to the edge of the light — and it is genuinely extensive, matching the "amazing coral cover" in Anderson's field note (e.g., Image 3).

3

The one close reef frame is the most informative on composition: dense fine-branched yellow-green thickets, cream knobby branches, gray-green digitate colonies with polyps fully expanded, and foliose plates packed together with almost no bare substrate between them (e.g., Image 1).

1

The macro frame is a tan-gold branching colony with its polyps out, growing over pink crustose coralline algae with a red-orange encrusting sponge alongside it (e.g., Image 2).

2

Coral cover

• Coral cover has not been estimated for this site.
• Mugia was a night dive shot as macro rather than reef-scale frames, so no computer vision figure applies and none is published.

Stressors

A crown-of-thorns starfish was photographed on this dive. Two frames show a large Acanthaster-type crown-of-thorns starfish — pale blue-gray body, orange-tipped spines, out, and active in the open as they are at night — and the substrate immediately around it in both frames is turf-covered dead branching rubble rather than living thicket, with only a laminar gray-brown plate and a few live branches surviving at the frame edges (e.g., Image 5, Image 9).

59

The two frames show the same animal from two angles, beside the same plate colonies. A foliose plate behind the starfish carries a pale patch in both frames, but under night flash it cannot be called a feeding scar, so this is recorded as a crown-of-thorns presence with associated dead substrate, not as documented active predation. No bleaching and no disease were seen, with the color caveat under Other notes standing.

Fish and other fauna

A turtle resting on the foliose plate bed across two frames; the frames do not settle green against hawksbill (e.g., Image 4).

4

Anderson's field note adds a whitetip reef shark and a huge cuttlefish, and records a hunt for walking sharks here without luck — they had turned up in numbers five nights earlier at Pantai Falajawa.

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.

Dive record

Mugia was a night dive on 13 August 2026, the fourth and last dive of that day on the August 2026 Halmahera crossing aboard the liveaboard Ambai (Wallacea Dive Cruises), to a maximum of 17.6 m in 24-25°C water, on the same day as Jerot, where Anderson logged 22-25°C and weird thermoclines and wondered in the log whether this is an upwelling area.

Other notes

Only six still frames survive the dive, plus one movie clip and a set of raw files, and all six were reviewed. Every one is a flash exposure against a black background, which is the photographic evidence that settles the dive as nocturnal, and it also means no site cover figure is published here and that color cannot be used to score bleaching: nocturnal flash whitens branch tips and washes out pigment, and coral polyps are expanded, both of which imitate pallor. Anderson's field note: “turtle, white tip, huge cuttlefish, hunted for walking sharks but no luck, amazing coral cover.”