N. GBR - Pink (AUHI159)

Setting

Hilder Reef's first dive of the day traced a steep slope flattening at 20 m, in visibility no better than 10 m, and the point-count survey read 70% live coral.

General benthic features

Nine or ten frames show dense, structurally complex reef: bright pink and mauve Pocillopora-type thickets run in banks across the crest (e.g., Image 6, Image 7, Image 8, Image 10, Image 11), with tabulate and corymbose Acropora carrying pale growing tips (e.g., Image 9, Image 10, Image 12, Image 13), cream and tan knobby massive Porites domes set among them (e.g., Image 11, Image 13), orange and rust-red encrusting sheets and foliose colonies (e.g., Image 8, Image 13, Image 14), purple and mauve encrusting patches, orange sponge, and crinoids tucked into the framework.

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Image 14 looks along a near-vertical buttress carpeted in a tan-and-pink branching thicket with orange colonies on the overhang — the steep-slope habitat of this site. Image 15 shows dimmer, pale mound-and-rubble ground at the transition.

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Elsewhere table Acropora, Stylophora pistillata, Porites cylindrica, and massive Porites filled out a more typical community.

Coral cover

• Reference: Khaled bin Sultan Living Oceans Foundation, Global Reef Expedition (in situ transect)
• Coral cover 70%, from the LOF-GRE in situ diver point-count transects (Global Reef Expedition site data, 933 sites). Anderson's own by-eye estimates on his six transects (9-21 m) ran 1-25% live coral, mostly 15-20%; he put the 5 m band at about 20%, mainly soft corals, and noted one soft-coral species dominating the entire site, so the transect figure sits well above his in-water impression.
• Transect mean 63 ± 9.6% SE (n = 9 transects; Living Oceans Foundation per-transect benthic data); the headline above is the expedition's station value (the headline weights each depth equally).

Stressors

Against that, three frames record the damaged ground Anderson logged at around 10 m: a broad, low-relief field of loose broken branch fragments, dead skeleton dulled to gray-white and already taking algal film, lying across pavement with only isolated survivors left standing — a blue-gray mounding colony and a few small pink corymbose colonies among the debris (e.g., Image 4, Image 5), with a further frame of largely dead branch rubble carrying black wire corals and one brown foliose colony (e.g., Image 3).

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These are dead, broken skeletons rather than live bleached tissue, and no bleaching extent is inferred from them. No disease lesions and no crown-of-thorns seastars are visible in any frame. He put the branch-rubble damage down to a relatively recent storm; live cover crashed to about 1% there, though some fire coral was already regrowing. Separately, sickly Seriatopora hystrix turned up at a couple of transects.

Comparisons with other data

No other surveys have been conducted at this site to date. Within 5 km, one independent station, AIMS manta tow at HILDER REEF, 2.74 km away, read 5.5–40% between 1994 and 2023.

Other notes

The 15 frames show both halves of the site. One frame is a survey working frame, with the yellow transect tape running away across the reef (e.g., Image 2).

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