Chagos Archipelago - Salomons Island (BISA94)

Setting

BISA94 is a protected submerged lagoonal patch reef inside Salomon atoll at 19.0 m, surveyed 25 April 2015.

General benthic features

Bare substrate and invertebrates are both under 5%, so the benthos is essentially coral or fleshy algae. Across 28 genera the assemblage is massive- and fleshy-dominated: Porites 19.37% of the benthos, 48% of all coral, and Goniopora 10.90%, three-quarters of the coral between them, while Acropora is effectively absent at 0.086%, one five-hundredth of the coral, an extreme for a Chagos site.

Coral cover

Formal transects recorded 40.3% coral against 50.5% algae — 50th of 109 Chagos sites for cover but 23rd for algae — and here algae means genuine fleshy growth rather than pavement: turf alone is 20.4% of the benthos, the 3rd-highest turf value of all 109 sites, with macroalgae a further 17.6% and coralline algae only 11.3%. The depth finding is a collapse: 63.2% coral at the shallowest stratum, 46.8% at the next, then 10.8% against 80.0% algae at the deepest, where only two genera remain on the entire transect. That deepest stratum is a single transect yet carries a third of the headline number — transect-weighting the same data would give 52.04% instead of 40.26% — so the published figure describes no depth at this site. The image cover figures (CoralNet 36.7%, Coralscapes 28.7%) rest on those same two frames and must not be averaged with the transect value. Coral cover: 40%. Live hard coral measured on the in situ benthic transects of the LOF BIOT-1 expedition (Mayfield & Dempsey 2026, Oceans, supplemental S1), against algal cover of 50.5% of the benthos. The transect figure is this site's authoritative cover value; no image-derived product overrides it. Across methods the same reef reads: transects 40.3% · CoralNet points 36.7% · Coralscapes masks 28.7% (2 frames). These products have different sampling footprints and denominators and should not be averaged.

Stressors

Bleaching on the canonical % bleaching (2nd training) column is 2.78%, 91st of 110 dives, lower quartile, with both runs agreeing. Condition cannot really be assessed: only two frames were retained, one an out-of-focus macro, and neither shows unambiguous bleaching, crown-of-thorns, or disease (e.g., Image 1, Image 2) — absence of evidence over two images, not a clean bill of health.

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Comparisons with other data

No independent survey was made at this exact site; the nearest ones are listed in the table below.