Alor - Motonglang (Cathedral)

Setting

A steep, heavily overgrown wall and pinnacle system consistent with the site's "Cathedral" name: one frame shows a narrow, vertical keyhole-shaped swim-through/arch cut through the rock, its walls dark with encrusting growth and a diver at its upper end (e.g., Image 47).

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Visibility is good on the open-water/blue frames and more turbid/particulate close to the wall, consistent with a wall site with upwelling or current.

General benthic features

Elsewhere the wall face is essentially wall-to-wall encrusting cover rather than open rock: dense mats of red/maroon and pink encrusting sponge and coralline algae, interspersed with patches of green Halimeda-type algae, form a mosaic backdrop punctuated by discrete coral colonies — a round tan brain/faviid-type coral head, small plating colonies with pale growing margins, low mounding colonies with pin-cushion polyps, and a spiky orange soft coral or gorgonian (e.g., Image 20, Image 23, Image 34, Image 44).

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Black bushy growth (consistent with black coral, Antipatharia) recurs on shaded faces alongside a delicate white fan-shaped gorgonian sea fan (e.g., Image 48).

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Large barrel sponges (one prominent ribbed individual over a meter across) and cratered gray sponge colonies with multiple oscula project from the wall in several frames (e.g., Image 3, Image 4, Image 39).

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On the more open, current-swept sections the substrate turns to low-relief rock and rubble with scattered small coral heads, schooling fusiliers and other silvery planktivores streaming past in blue water, and at least three divers with slates/pointers visible working the wall (e.g., Image 26, Image 41, Image 46).

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Coral cover

• Reference: Claude CV point count (this site's photos)
• Coral cover: 5.8% — a blind Claude computer-vision point count of 132 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

One wire coral (a single whip-like black coral attached to the wall at its base) is stark white along its length: a bleached wire coral (photo not shown). Other wire corals on the wall are cream to tan (e.g., Image 26). Disease and physical damage were not seen on the coral colonies reviewed, and the only man-made objects are diver gear. No crown-of-thorns starfish (COTS) or other corallivores were evident.

Fish and other fauna

Reef fish recorded directly include small yellow damsels/butterflyfish, anthias, and a lined/striped fish resembling a lionfish tucked in the reef in one lower-wall frame (not confirmed with confidence) (e.g., Image 45, Image 50).

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Comparisons with other data

A steep wall with large openings, swim-throughs, and chamber-like spaces (e.g., Image 6, Image 35).

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Hard corals were discontinuous but diverse, with plates, scroll-shaped plating corals, massive corals, scattered branching Acropora, fungiids, and merulinid brain corals on illuminated ledges and outer wall surfaces (e.g., Image 14, Image 51, Image 52).

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A very large marbled ray (Taeniurops meyeni) is recorded in the dive log. Light shafts and abrupt sheltered-to-exposed transitions define a wall-and-cave system rather than a uniform coral slope (e.g., Image 19, Image 27).

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Regional context, not a survey of this site: Razak et al. (2026) found no significant trend in hard coral cover around Alor (a decline of 0.6% per year at 23 sites, surveyed by point-intercept transect at about 8–10 m in 2014, 2017, 2021, and 2023 by Yayasan WWF Indonesia); this is a trend for that location, not this site’s cover. Cover at those sites fell by 3% between the 2014 and 2017 surveys, which bracket 75 days of NOAA Bleaching Alert Level 1 from December 2016 to February 2017.