Chagos Archipelago - Peros Banhos (BIPB65)

Setting

BIPB65 is a leeward lagoonal patch reef in Peros Banhos (the nearest class on the LOF habitat map is lagoonal pinnacle reefs, massive coral dominated), surveyed 15 April 2015 on a dive to 25.2 m (e.g., Image 1, Image 2).

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General benthic features

The coral community is overwhelmingly dominated by Acropora, which accounts for about two-thirds of all coral cover, with Porites a distant second and twenty-one other genera making up a thin remaining tail. Crustose coralline algae cover 11% of the benthos and bare substrate 17% (LOF transects).

Coral cover

• Reference: Mayfield & Dempsey (2026)
• CoralNet submission package
• Transect coral cover is 47%, against 29% algal cover, with published image-based bleaching at 8.3%.
• Transect mean 47 ± 4.0% SE (n = 18 transects; Living Oceans Foundation per-transect benthic data); the headline above is this all-transect mean, and the published station value, which weights each depth equally, is 41% (Mayfield & Dempsey 2026, Oceans, suppl. S1).
• The bleaching percentage is a computer vision figure: CoralNet annotation of the informal survey images, not a diver's field estimate (Mayfield & Dempsey 2026, suppl. S1).

Stressors

In the photographs most colonies appear healthy and normally pigmented, but several branching corals show clear colony-scale white pallor beside fully pigmented neighbors, and a shark that resembles a nurse shark resting on the sand (e.g., Image 5) and a moray eel were also observed on the reef.

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Anderson's sampling sheet records nine colonies sampled here at 6.5–25.1 m: six Pocillopora acuta by RFLP; two Seriatopora hystrix by field call; one Pocillopora sp. sampled for a collaborator (field calls); the condition notes run from healthy to >90% bleached, with some partly dead colonies. Pocillopora acuta colonies from this archipelago were analyzed in Thomas et al. (2026, Global Ecology and Biogeography 35:e70305, https://doi.org/10.1111/geb.70305). The Living Oceans Foundation transects here recorded 0.1% cyanobacteria and 0.1% recently dead coral.

Comparisons with other data

Apart from the Living Oceans Foundation survey shown here, we found no other surveys at this site as of 2026. Within 5 km, one independent station, XL Catlin Seaview Survey at transect 36007, 3.34 km away, read 29% in 2015.

Other notes

Reef type follows Anderson's field sheet; on the LOF habitat map the pin lies 34 m from 'lagoonal pinnacle reefs - massive coral dominated' (38 m from the branching-coral class) inside the lagoon; a lagoon pin has no rim facing. Anderson's field sheet (LOF fellowship 2016 workbook) records 'lagoonal patch reef', 'leeward'; the expedition's 933-site table classes the station as 'protected' (patch reef).