Chagos Archipelago - Great Chagos Bank West (BITB48)

Setting

BITB48 is an intermediate-exposure submerged lagoonal patch reef on the inner side of Three Brothers, surveyed 24 March 2015; the published depth, temperature, and salinity cells are all blank, so the site is placed only by strata with no meter value on record.

General benthic features

Across 22 genera, 70th of 109, Porites leads at 11.97% of the benthos, 36.9% of the live coral, with Acropora at 9.27%, the two holding about two-thirds of the coral between them. The depth contrast is compositional rather than quantitative: cover barely moves, 34.5% to 30.4%, but the reef hands over from a shallow branching Acropora and Pocillopora patch reef on sediment-laden turf to a deeper massive-Porites and faviid ground over 26.9% bare rock, with Porites nearly doubling to 15.73% while Pocillopora and Leptastrea drop out to exactly zero. The algal budget is notable for sediment-laden turf at 13.16%, nearly rivaling the coralline algae at 14.71%.

Coral cover

Fourteen formal transects recorded 32.4% coral against 37.0% algae — 71st of 109 Chagos sites for cover and 63rd for algae, both mid-pack — with 19.0% bare substrate and 11.6% non-coral invertebrates, and individual transects spanning 12% to 62%, so the tidy site figure averages very unequal ground. The transect figure is its only cover number. Coral cover: 32%. 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 37% of the benthos. The transect figure is this site's authoritative cover value; no image-derived product overrides it.

Stressors

Condition cannot be assessed at all: no photographs exist for this site anywhere, under any prefix or casing, so there are no CoralNet or Coralscapes products, no multi-method comparison, and no observation of bleaching, disease, predation, crown-of-thorns, or fauna — these are unavailable, not zero. The published Mean(%bleaching) cell is likewise blank, in both CoralNet training runs, so the site contributes nothing to any archipelago bleaching statistic.

Comparisons with other data

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