Chagos Archipelago - Salomons Island (BISA92)

Setting

BISA92 is a windward fore reef outside Salomon lagoon, surveyed 25 April 2015 on a dive to 30.2 m (e.g., Image 1, Image 3).

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General benthic features

What holds the wall is not coral — non-coral invertebrates take 27% of the benthos, more than the coral does, with coralline algae a further 20%, and the photographs show sponge- and ascidian-carpeted panels, meter-wide gorgonian sea fans, and black wire corals (e.g., Image 2, Image 4).

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Porites leads at 8.3% of the benthos, 32% of all coral, with 24 genera under 1%.

Coral cover

• Reference: Mayfield & Dempsey (2026)
• CoralNet submission package
• It is a clear case of a reef whose grandeur and whose cover number point opposite ways: formal transects recorded only 26% coral, against 42% algae, yet genus richness is 31 genera.
• Transect mean 26 ± 2.4% 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 24% (Mayfield & Dempsey 2026, Oceans, suppl. S1).
• The five strata are not a gradient but a rise, two falls, and a rebound — 18%, 35%, 23%, 18%, 28% — invertebrate cover peaking at 36% mid-profile, and the deepest stratum (a single transect) carries an eight-genus assemblage, seven of its genera also found shallower, that supplies all of the site's Hydnophora and much of its Montastrea and Pachyseris.
• 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 9.1% (CoralNet analysis of the survey images; Mayfield & Dempsey 2026, suppl. S1). Several pale-to-white branching colonies sit among pigmented neighbors at the reef top (e.g., Image 5), encrusting and massive colonies stand stark white among pigmented ones on the wall, and two large sea anemones have stark white tentacles (e.g., Image 39) — genuine thermal stress, though anemones are not scleractinian and enter neither the cover nor the bleaching figures.

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No crown-of-thorns or disease. Anderson's sampling sheet records eight colonies sampled here at 8.6–29.8 m: two Seriatopora hystrix by field call; five 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 no cyanobacteria and 0.1% recently dead coral.

Comparisons with other data

Perry et al. (2015) surveyed a nearby station (Ile Takamaka, Salomon) in March 2015, 0.47 km from the pin; we could not confirm that it is the same reef. Cover values from that work are not among the survey records shown on this page. Within 5 km, three independent stations recorded station-year means of 9.9–43% hard coral cover between 2006 and 2020; the nearest of these, Lange et al. (2021) at Salomon Atoll, 3.23 km away, read 9.9–43% between 2006 and 2020.

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 off the east-facing outer reef of the eastern island, windward of the southeast trades, consistent with the sheet.