Chagos Archipelago - Speakers Bank (BISP115)

Setting

BISP115 is a protected submerged bank reef inside the Speaker's Bank lagoon at 20.1 m, surveyed 3 May 2015.

General benthic features

Only 14 genera were recorded, 98th of 109 for richness, six of them holding 98% of the coral: Porites 37%, Acropora 27%, then Montipora, Platygyra, Pocillopora, and Stylophora.

Coral cover

Formal transects recorded 42.2% coral against 44.8% algae — 44th of 109 Chagos sites for cover, 35th for algae — with coralline algae taking 25.3% of the benthos, 10th-highest of 109. Only two depth transects exist, and they invert completely — the shallower is Acropora-led at 20.0% of benthos against Porites 7.4%, while the deeper carries more coral, not less, at 48.0%, with Porites at 24.0% and Acropora down to 3.0%, so the site-level order that puts Porites first is entirely an artifact of that deep transect. No CoralNet or Coralscapes product exists for this site either, so the transect figure is its only cover number. Coral cover: 42%. 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 44.8% of the benthos. The transect figure is this site's authoritative cover value; no image-derived product overrides it.

Stressors

Condition is the finding, and the published record cannot carry it: the bleaching cell is blank, one of 11 of 109 Chagos sites with no value in either CoralNet run, so this site contributes nothing to any archipelago bleaching statistic. The photographs show unambiguous colony-scale bleaching in at least five of the frames reviewed — a bone-white table sitting on a dead one (e.g., Image 2), a cream-white branching colony flanked by pigmented neighbors, a wide view with numerous small white colonies scattered among pigmented ones (e.g., Image 1), so a distributed condition rather than a few individuals.

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No disease, predation, or crown-of-thorns was seen (e.g., Image 3, Image 4).

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Comparisons with other data

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