Alor - Pasir Merah (Red Sand)

Setting

A heterogeneous volcanic slope of sand, rubble, and red or pink encrusted substrate interspersed with coral outcrops (e.g., Image 5, Image 7, Image 23).

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Visibility is good throughout with strong ambient light. A reef-to-wall transition with locally enhanced water movement; the gas vents reported for the site were not clearly captured (e.g., Image 27).

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General benthic features

The opening frames confirm the site's name: a reddish-brown sediment/rubble plain (a mix of fine sand and small coral fragments giving it a distinctive rust-red hue) with only isolated small coral colonies (a pale mounding head, a purple encrusting patch, small faviid heads) and a black damselfish with an orange-tipped tail (e.g., Image 16, Image 51).

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Further along the dive, the habitat becomes a dense low-relief coral garden: massive Porites and Platygyra-type brain corals with maze-like grooved surfaces, foliose plating colonies with pale rims, and large anemones (one brown carpet-type, one smaller) each hosting anemonefish (e.g., Image 2, Image 17, Image 21, Image 40).

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Black bushy growth consistent with black coral, a maroon/purple crinoid feather star, and a blue Linckia sea star recur on the reef structure (e.g., Image 30, Image 44).

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Coral cover is patchy rather than uniform: dense clusters of massive and plating corals alternate with open white sand patches hosting only scattered small colonies, consistent with a mixed sand/coral mosaic rather than continuous reef framework (e.g., Image 22, Image 32, Image 42).

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Coral cover

• Reference: Claude CV point count (this site's photos)
• Coral cover: 16% — a blind Claude computer-vision point count of 174 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

Fishing gear: a woven-bamboo fish trap (bubu) sits on the reef slope behind a large leather coral (e.g., Image 10), and thin trap lines run over the reef and up into the water column on at least seven frames along the dive; one, fouled with algae, lies draped across colonies.

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One gray-white to stark-white lobed patch is a mix of recently dead soft and hard corals, cause unclear (e.g., Image 55).

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Other colonies show normal brown/tan/olive pigmentation, with white growing rims on plate margins. A computer-vision point count called 0.2% of coral points bleached (1 of 174 photos), which the photographs could not confirm. No crown-of-thorns starfish (COTS) or other corallivores were evident.

Fish and other fauna

Anthias, chromis, and other damselfishes were locally dense above the slope (e.g., Image 18, Image 39, Image 54).

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Comparisons with other data

We found no other surveys at this site as of 2026. Within 5 km, one independent station, WWF-US / WWF-Indonesia at station 5003, 0.99 km away, read 24% in 2014.

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.

Other notes

One wide frame shows a large school of dozens of small dark fish (chromis/damsel-type) streaming along the reef edge in blue water with two divers visible in the distance (e.g., Image 8, Image 12, Image 13).

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