Chagos Archipelago - Peros Banhos (BIPB67)

Setting

BIPB67 is an emergent fringing forereef on Peros Banhos, surveyed on 16 April 2015 at 29 m under intermediate wave exposure.

General benthic features

Porites and Acropora lead the assemblage at roughly 15% and 13% of the benthos, though the balance shifts strongly with depth, from an Acropora-dominated shallow zone to Porites-dominated deeper ground. The reef alternates between dense multi-genus coral thickets and stretches of low-cover pavement and rubble, with a gray reef shark and a large grouper among the fish recorded (e.g., Image 1).

1

Coral cover

Formal transects recorded 42% coral cover against 37.5% algal cover, with 4.9% of coral colonies showing signs of bleaching, a comparatively low figure for the archipelago. 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 15–16 points lower than the transects (CoralNet 26.1%, Coralscapes 26.9%); the three are not interchangeable and should not be averaged (see the full report).

Stressors

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

Comparisons with other data

No prior survey data from this site. If you would like to share yours, please email us.