### BIDI14 — Danger Island
**Date:** 2015-03-13
**GPS:** 6.40987°S, 71.25622°E
**Frames reviewed:** 13 of 13 (100% of the site folder, `BiDi14-finished`)
**Coral cover:** 15.2% (formal transect surveys) · **% bleached:** 9.8% (CoralNet analysis of informal survey images; Mayfield & Dempsey 2026, Oceans)
**Live hard coral cover across methods** (n=13 photos): transect 15.2% · CoralNet points 16.2% · Coralscapes 12.4%. Deviation vs transect -2.8 to +1.0 pp. **Mean of 3: 14.6% ± 2.0** — the second-tightest agreement in the archipelago after BIDI10, and for the same reason: low cover on low-relief substrate.
**Coral genera identified:** 7 scleractinian + 1 hydrocoral — *Acropora* (digitate/corymbose and plating), *Pocillopora*, *Porites* (massive domes), *Platygyra*/*Leptoria*, *Favites*/*Goniastrea*, *Montipora* (encrusting), *Astreopora*; hydrocoral *Millepora*. Growth-form calls from photographs, given as "compatible with".
**Representative photos:** P3130267.jpg, P3130258.jpg, P3130255.jpg, P3130257.jpg, P3130247.jpg

BIDI14 is a **protected patch reef on low-relief, heavily coralline-encrusted pavement**, and its 15.2% cover is honestly represented by the photographs. The substrate through P3130246, P3130256, P3130259 and P3130270 is a pink and mauve crustose-coralline hardground strewn with rubble, carrying widely spaced digitate and corymbose *Acropora*, small *Pocillopora*, domal *Porites*, meandroid brains compatible with *Platygyra* or *Leptoria*, encrusting *Montipora* and occasional yellow *Millepora*. Nothing here forms continuous framework; the reef reads as a mosaic of individual colonies on consolidated pavement. P3130247 is the most diverse single frame — pink-purple knobby and encrusting colonies, massive *Porites*, tan encrusting sheets and dense coralline, with a regal angelfish (*Pygoplites diacanthus*) in the corner.

**Bleaching is the most substantial content at this site, and at 9.8% it is the second-highest figure at Danger Island.** Three frames carry it clearly. **P3130267 is unambiguous** — a small *Pocillopora*-type colony bleached wholly cream-white, sitting on CCA-crusted pavement among fully pigmented yellow-green and pink encrusting neighbours. **P3130257 and P3130260** both show larger branching *Acropora* colonies with **cream-white branch tips over dark red-brown bases** — an extensive apical paling that goes well beyond the few-millimetre growth margin seen at BIEG04, and on colonies whose lower branches are simultaneously darkening. Taken with the site's 9.8% figure, these read as genuine early thermal paling rather than growth tips, though a single-visit photograph cannot fully separate the two.

A second condition signal is independent of bleaching: **P3130255 shows a grey-purple meandroid brain coral with a distinct pink-and-white lesion patch on its upper surface** — bare skeleton with a pigmented margin, adjacent to healthy tissue. This is the third lesioned massive coral found in the Danger Island group (with BIDI10/P3120278 and BIDI13/P3130381), and the recurrence across three sites is worth noting even though none can be diagnosed from imagery.

**P3130258 is the site's methodology frame and one of the best in the collection**: a transect line runs clearly across the reef with a diver working in the background, and the same frame happens to hold a regal angelfish, a red-orange coral hind compatible with *Cephalopholis*, a meandroid brain, yellow *Millepora* and a large domal *Porites* — the survey and the assemblage in one image. A second diver appears in P3130256.

Faunally the dive is dominated by schooling planktivores and mid-water predators. Emperors or breams compatible with *Monotaxis grandoculis* — silvery with the characteristic large yellow-rimmed eye — school over the reef in P3130246 and P3130247. Blue-and-yellow fusiliers compatible with *Pterocaesio* or *Caesio* fill P3130268, P3130269 and P3130270, and dark-bodied snappers or rudderfish compatible with *Macolor* or *Kyphosus* run along the deeper slope in P3130270. **A grey reef shark compatible with *Carcharhinus amblyrhynchos* crosses the blue in P3130272.** Reef fish include the two regal angelfish noted above, Moorish idols, surgeonfishes and the coral hind.

<b>Assemblage composition.</b> The cover line carries the numbers, and BIDI14 is a second clean confirmation of the growth-form argument developed at BIDI08/BIDI10. Here transect (15.2%), CoralNet (16.2%) and Coralscapes (12.4%) all fall within 4 pp of one another — **±2.0, the second-tightest spread in the archipelago** — on a reef whose coral is low-relief, discrete and lying essentially in the plane of the substrate. Together with BIDI10 (±1.0) and against BIDI08 (−25 pp, tabular), the pattern is now supported by three independent Danger Island sites: **methods agree where relief is low and disagree where cover is carried by horizontal plates.**

**Flags:** (1) **Second-highest bleaching at Danger Island (9.8%)**, supported by P3130267 (wholly bleached *Pocillopora*) and the apical paling in P3130257/P3130260. (2) The white branch tips in P3130257/P3130260 are read as **early thermal paling, not growth tips** — the affected zone is far larger than the growth margin at BIEG04 and the basal tissue is darkening — but a single visit cannot fully exclude the alternative; flagged as such. (3) **P3130255: pink-and-white lesion on a meandroid brain** — the third lesioned massive in the Danger Island group (see BIDI10/P3120278, BIDI13/P3130381). Three sites, three lesions; worth a targeted look even though none is diagnosable from photographs. (4) **P3130258 is an outstanding combined methodology/assemblage frame** (transect line, diver, angelfish, hind, brain, *Millepora*, *Porites*). (5) The small white cup-shaped objects on the pavement in P3130256 are unresolved — bleached recruits, ascidians or molluscs; do not score as coral. (6) Grey reef shark in P3130272. (7) No per-frame depth data.

**Benthic data:** [Download BIDI14 benthic survey data (CSV)](../benthic_data/BIDI14_benthic.csv) — scleractinian cover by genus with full names, plus substrate and algal categories (bare substrate, CCA, turf, macroalgae, invertebrates), from the LOF BIOT-1 survey (Mayfield & Dempsey 2026, *Oceans*, supplemental file S1).