Chagos Archipelago - Salomons Island (BISA102)

Setting

BISA102 is a deep side-on fore reef outside Salomon atoll, surveyed 28 April 2015 on a dive to 29.7 m (e.g., Image 1).

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General benthic features

Across 24 genera the assemblage is Porites-led rather than Acropora-led, Porites holding 40% of all coral, Pocillopora 21%, and Acropora only 10%. Down the profile the Porites share rises from 34–39% in the two shallower strata to 52–58% in the two deeper ones, while genus richness collapses from 22 genera in one stratum to just five in the deepest, where invertebrates take 39% of the ground.

Coral cover

• Reference: Mayfield & Dempsey (2026)
• CoralNet submission package
• Formal transects recorded 32% coral against 33% algae, but the number that defines the site is neither: non-coral invertebrate cover is 29% of the benthos, nearly as much as the coral itself, and the photographs identify it as anemones with resident anemonefish, soft corals, encrusting sponges, and gorgonians.
• Transect mean 32 ± 2.4% SE (n = 16 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 31% (Mayfield & Dempsey 2026, Oceans, supplemental S1).
• Live hard coral measured on the in situ benthic transects of the LOF BIOT-1 expedition (the mean of all of this station's transects), against total algal cover (all algal groups) of 33% of the benthos.
• Image-based estimates (CoralNet, DINOv3, CoralSCOP, and Claude) are listed in the method table for comparison only; the transect figure is this site's cover value.

Stressors

Published bleaching is 19%, and the imagery agrees: a branching colony stark white across every branch beside pigmented neighbors of the same size, three adjacent white colonies in another frame, a white corymbose colony against a healthy massive Porites (e.g., Image 3).

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No crown-of-thorns, disease, or predation was seen. The Living Oceans Foundation transects here recorded under 0.1% cyanobacteria and under 0.1% recently dead coral.

Fish and other fauna

A silvertip-type shark, two giant morays, and an octopus were photographed, and one frame is a blue-light fluorescence shot (e.g., Image 2).

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Comparisons with other data

The XL Catlin Seaview Survey covered a nearby station (transect 36017) in 2015, 0.43 km from the pin; we could not confirm that it is the same reef. Within 5 km, four independent stations recorded station-year means of 22–32% hard coral cover between 2006 and 2015; the nearest, XL Catlin Seaview Survey at transect 36017, 0.43 km away, read 22% in 2015.

Dive record

Anderson's afternoon dive on 28 April 2015 entered the water at 15:04 and lasted 54 minutes, to a maximum depth of 29.7 m (the field sheet); the notes call it a “spectacular wall dive” and record extensive bleaching of digitate acroporids and pocilloporids, at least 50% of each. Anderson sampled two pocilloporid colonies (Pocillopora sp.) for a collaborator: ChJo266 (collected 15:26 at 16 m; 50% bleached, at the edge of the thermocline; in a random survey of about 30 colonies, about half of the pocilloporids were bleached) and ChJo267 (15:32, 14 m; more than 90% bleached, pigmented only in the interior, near 30°C above the thermocline). 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).

Other notes

Anderson's field sheet (LOF fellowship 2016 workbook) records 'forereef' and leaves the aspect blank; the expedition's 933-site table classes the station as 'exposed' (fringing reef). No LOF habitat map covers Salomon atoll (the LOF Chagos habitat map covers only Peros Banhos), the field sheet gives no aspect, and the station's GPS position does not settle the aspect (relative to the prevailing southeast trade winds, it reads side-on from the atoll's center and windward from the nearest reef edge), so the aspect printed above is read from the station's position on satellite imagery (Esri World Imagery): the pin lies off the southwest tip of the atoll's outer reef, which faces southwest, side-on to the prevailing southeast trade winds.