Chagos Archipelago - Salomons Island (BISA97)

Setting

BISA97 is a channel patch reef in the Salomon lagoon near the north-west pass, leeward on Anderson's field sheet, surveyed 26 April 2015 on a dive to 15.5 m; the notes describe a murky lagoon site near the channel with high coral cover and diversity, a mix of back-reef and fore-reef corals, and calm water with no current.

General benthic features

Acropora leads at 19% of the benthos — 34% of all coral — but Porites at 11% and Goniopora at 6.4% are substantial, and the fleshy and massive component is well represented: Merulina 4.9%, Goniastrea 3.0%, Lobophyllia 2.5%, Favia 1.7%, Galaxea 0.9%, and Pavona 0.8%. Sixteen further genera fall below 0.5%, including Isopora, Ctenactis, Halomitra, Pachyseris, and Millepora. Bare substrate and coralline algae hold 10% of the benthos each, non-coral invertebrates 9.5%, turf 8.1%, and macroalgae 3.0%. The reef has strong local continuity. One frame shows numerous compact branching colonies packed across the substrate with little open sand; two others add large massive and lobate colonies; two more show tables and corymbose fields extending into the middle distance; and another shows the assemblage continuing across a broad shallow surface (e.g., Image 3, Image 5).

35

Crevices remain between colonies, but living coral occupies much of the visible hard bottom in most frames. The benthic palette includes pink and purple encrusting surfaces, brown foliose growth, small meandroid colonies, and smooth massive heads — the visible counterpart to a 9.5% non-coral invertebrate figure and a genus list this long (e.g., Image 2).

2

The photographs document a densely packed shallow coral garden with massive heads, tables, foliose forms, and heavy encrustation, plus convincing bleaching in both branching colonies and one large table.

Coral cover

• Reference: Mayfield & Dempsey (2026)
• CoralNet submission package
• 55% against 25% algae, and the assemblage carries 28 non-zero coral genera with no single genus taking more than 34% of the coral.
• Transect mean 55 ± 3.2% SE (n = 11 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 54% (Mayfield & Dempsey 2026, Oceans, suppl. S1).
• The two depth strata differ in composition more than in cover.
• D2 carries 51% coral across 21 genera and is the Acropora band — 28%, with Porites 12% and Goniastrea 3.3%.
• D3 carries slightly more coral at 58% across 22 genera but the order flattens completely: Acropora falls to 14% while Porites holds 10%, Goniopora rises to 10%, and Merulina to 7.7%.
• Formal surveys give 55% coral, 25% algae, and 9.5% non-coral invertebrates across 28 genera, led by Acropora in the shallow band and shared between Porites, Goniopora, and Merulina in the deeper one.

Stressors

Published bleaching is 8.8% (CoralNet analysis of the survey images; Mayfield & Dempsey 2026, suppl. S1), and Anderson's notes record very bad bleaching in P. verrucosa, with almost all colonies at the site badly bleached. One frame shows several compact and thick-branched colonies uniformly cream-white while adjacent colonies retain brown, purple, or green pigmentation (e.g., Image 13).

13

Another frame centers a very large table colony pale to white across nearly the entire plate (e.g., Image 9).

9

Other wide frames contain scattered white colonies, including pale tables and compact branches. Anderson's sampling sheet records 11 colonies sampled here at 10.5–15.4 m: five Pocillopora acuta and one P. damicornis by RFLP; two Seriatopora hystrix and one Seriatopora sp. by field call; one P. verrucosa and one Pocillopora sp. sampled for a collaborator (field calls); the condition notes run from healthy to 100% 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). One very large massive colony is partly bleached: its broad upper lobes are cream-white with live tissue, beside tan lobes of the same colony (e.g., Image 15).

15

The Living Oceans Foundation transects here recorded 0.3% cyanobacteria and no recently dead coral.

Fish and other fauna

Fish use the coral relief heavily. Two frames show schools of small fishes concentrated around a large bommie with larger reef fishes above the structure, and a third shows another school in open blue water beyond the coral field (e.g., Image 1).

1

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, eight independent stations recorded station-year means of 6.8–63% hard coral cover between 2006 and 2020; the nearest, XL Catlin Seaview Survey at transect 36013, 0.86 km away, read 28% in 2015.

Other notes

Aspect follows Anderson's field sheet (LOF fellowship 2016 workbook: 'channel patch reef', 'leeward'); the expedition's 933-site table classes the station as 'protected' (channel reef). Esri World Imagery (no LOF habitat map covers Salomon atoll; the LOF Chagos habitat map covers only Peros Banhos) puts the pin inside the Salomon lagoon near the north-west pass, consistent with the sheet.