Chagos Archipelago - Salomons Island (BISA93)

Setting

BISA93 is a fore reef on the seaward side of Salomon, windward on Anderson's field sheet, surveyed 25 April 2015 on a dive to 30.9 m.

General benthic features

Genus richness is the site's strength: 34 genera, including the Indian Ocean endemic Ctenella, on a reef where Porites alone holds 52% of all coral (e.g., Image 3, Image 4).

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Coral cover

• Reference: Mayfield & Dempsey (2026)
• CoralNet submission package
• Formal transects recorded 41% coral against 31% algae, with bare substrate very low at 5.1% and non-coral invertebrates at 22%, visible in the imagery as gorgonian sea fans, black whip corals, and barrel sponges (e.g., Image 2).
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• Transect mean 41 ± 4.2% SE (n = 19 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 39% (Mayfield & Dempsey 2026, Oceans, supplemental S1).
• The depth profile is a sharp peak and a collapse — 38% coral shallow, a 59% second stratum where Porites reaches 37% of the benthos, then 39% at the most genus-diverse band with 26 genera, then a fall to 20% at the deepest, where algae takes 41%, bare substrate 17%, and Acropora is essentially gone at 0.5%.
• 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 31% 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 12% (CoralNet analysis of the survey images; Mayfield & Dempsey 2026, suppl. S1). Stark-white plating and massive colonies stand beside pigmented plates, massive and branching colonies in many of the photographs (e.g., Image 1, Image 5, Image 12, Image 29), and one massive colony is white across half its surface (e.g., Image 10).

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No crown-of-thorns, disease band, or fresh predation scar in any frame. Anderson's sampling sheet records eight colonies sampled here at 10.0–30.9 m: three Seriatopora hystrix and one Seriatopora sp. by field call; three Pocillopora sp. and one P. verrucosa sampled for a collaborator (field calls); the condition notes run from healthy to 100% bleached. 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 0.3% cyanobacteria and under 0.1% recently dead coral.

Fish and other fauna

Bluefin trevally were photographed hunting baitfish and a grazing school of thirty-plus parrotfish crossing the reef (e.g., Image 13, Image 24).

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Comparisons with other data

Perry et al. (2015) surveyed a nearby station (Ile de Passe, Salomon) in March 2015, 0.28 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 6.8–63% hard coral cover between 2006 and 2020; the nearest of these, XL Catlin Seaview Survey at transect 36016, 0.66 km away, read 19% in 2015.

Other notes

Aspect follows Anderson's field sheet (LOF fellowship 2016 workbook: 'fore reef', 'windward'); the expedition's 933-site table classes the station as 'exposed' (fringing reef). Esri World Imagery (no LOF habitat map covers Salomon atoll; the LOF Chagos habitat map covers only Peros Banhos) puts the pin about 100 m off the outer reef at the north-north-east tip of Salomon, facing north-north-east: side-on or leeward for the southeast trades (about April to November) and closer to windward for the northwest monsoon winds (about November to March); the aspect shown is the sheet's label.