Chagos Archipelago - Peros Banhos (BIPB64)

Setting

BIPB64 is an emergent fringing forereef on Peros Banhos, surveyed at intermediate wave exposure to a maximum depth of 27 m.

General benthic features

Porites is the leading genus at just under 9% of the benthos, followed by Acropora, Pocillopora, and Montipora, and coral cover declines with depth as algae takes over the deeper transects. Photographs show a structurally complex reef alternating between dense coral thickets and open sand-and-rubble flats, with sheltering sweetlips, triggerfish, and anemones hosting anemonefish (e.g., Image 1, Image 2, Image 3, Image 5, Image 6, Image 9, Image 10, Image 12, Image 13, Image 14, Image 18, Image 19, Image 25).

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Coral cover

Published surveys recorded 31% live coral cover against a higher 42.7% algal cover, with 9.5% of coral imagery showing signs of bleaching (e.g., Image 8, Image 15, Image 16, Image 20, Image 21, Image 22, Image 24, Image 26, Image 27).

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The bleaching percentage is a computer vision figure — CoralNet annotation of the informal survey images, not a diver's field estimate — and human-vs-model agreement is weaker for bleaching (r = 0.40) than for coral cover (r = 0.72). Image-based methods read this reef 14–17 points lower than the transects (CoralNet 14.6%, Coralscapes 16.8%); the three are not interchangeable and should not be averaged (see the full report).

Stressors

Several colonies show clear, colony-scale bleaching consistent with the published figure, including one large table coral photographed almost entirely white (e.g., Image 4, Image 17).

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No crown-of-thorns starfish (COTS) or other corallivores evident.

Comparisons with other data

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