Chagos Archipelago - Great Chagos Bank West (BICC36)

Setting

BICC36 is a deep submerged bank reef in Central Chagos, forereef aspect under intermediate exposure at 34.4 m, surveyed 20 March 2015.

General benthic features

Coralline algae alone takes 25.9% of the benthos, 8th-highest of 109, while fleshy turf is just 4.85%, and non-coral invertebrates hold a further 25.8%. Only 11 genera were recorded, 104th of 109, with Acropora, Porites, Pocillopora, and Montipora holding 86% of the little coral present.

Coral cover

It is one of the lowest-cover sites in the archipelago: 5.8% coral against 60.4% algae, 106th of 109 Chagos sites for cover and 6th for algae — but that algae is hard pavement, not weed (e.g., Image 2, Image 4).

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The two depth strata run in opposite directions: the shallower carries 9.8% coral in a four-genus assemblage over turf-and-sediment ground, while the deeper collapses to 1.8% as coralline algae quadruples to 41.6% and Pocillopora replaces Acropora as leading genus — though that stratum rests on only two transects. Unusually, the image methods read higher than the transects here — CoralNet 13.1%, Coralscapes 7.7% against 5.8% — the known over-read on low-cover reefs.

Stressors

Published bleaching is 6.4%, mid-pack at 58th of 98 on the site table's Mean(%bleaching) column, the first CoralNet training run rather than the canonical % bleaching (2nd training) column, and the 15-frame review found no unambiguous pallor, no disease, no crown-of-thorns.

Fish and other fauna

The macrofauna is the set's strength: a spiny lobster, a large octopus, a mantle-extended cowrie, and a glassfish shoal over black coral (e.g., Image 1, Image 3).

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Comparisons with other data

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