BVI - Necker Island snorkel

Setting

The 43 in-water frames are shallow snorkeling - the surface is in shot repeatedly, so most of this is roughly 1-5 m (e.g., Image 7, Image 12).

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General benthic features

The dominant impression is structure without much live tissue. Frame after frame shows standing dead acroporid framework: whole elkhorn (Acropora palmata) thickets and staghorn (A. cervicornis) rubble fields, gray and algae-filmed, over pavement coated in red turf, crustose coralline algae, and Dictyota-type brown macroalgae (e.g., Image 10, Image 17, Image 23, Image 24, Image 27).

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Several wide shots hold no live stony coral at all (e.g., Image 22, Image 44).

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Live cover is real but patchy and small-bodied. Two frames hold live Acropora - a golden A. cervicornis thicket with white growing tips, and one substantial live A. palmata table standing alone on dead pavement (e.g., Image 25).

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Fire coral is the most conspicuous live element - bladed Millepora complanata with white margins, and encrusting M. alcicornis sheeting over dead framework (e.g., Image 29, Image 33, Image 38, Image 42).

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Pale cream Porites porites finger clumps sprout from turf-covered massive mounds; mustard-yellow Porites astreoides lobes recur, repeatedly with pink coralline algae overgrowing dead margins (e.g., Image 13, Image 16, Image 26, Image 34).

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Grooved brain corals (Pseudodiploria strigosa) appear in five frames, mostly intact - but one has half the colony dead and red-turfed, and one pale massive colony carries a large bleached-white patch (e.g., Image 2, Image 18, Image 30, Image 43).

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Gorgonians carry the relief where coral does not: sea rods, sea plumes, and purple Gorgonia sea fans (e.g., Image 6, Image 31, Image 35, Image 39).

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Coral cover

Coral cover for this site is 14.3% - a CoralSCOP computer vision photographic index over 121 frames, not a diver transect, and worth weighing against what the frames show: this reef is full of coral-shaped dead skeleton (e.g., Image 4, Image 5, Image 20).

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Against independent point-count surveys it reads high, and the bias is ADDITIVE rather than multiplicative: against 273,968 Catlin Seaview photoquadrats within 2 km of these pins, the relationship is close to his value = their value + about 18 percentage points, with the index appearing to have a floor near 15-20% - it does not report near-zero even where a 50-point count finds 1.0-3.0%. Read a low figure here as an upper bound and a near-zero reef as unresolved, not as the number shown. Read this as a provisional photo-derived index, not a diver survey. Anderson is actively trying out other CV models and intends to redo this CoralSCOP-based figure once something more dependable comes along.

Stressors

No tissue-loss lesions of the SCTLD kind were identifiable in any frame.

Fish and other fauna

Fauna: a juvenile requiem shark on sand, two Caribbean spiny lobsters under ledges, a dark long-spined urchin, blue tangs, sergeant majors, bar jacks, brown chromis, and a maroon ball sponge (e.g., Image 3, Image 11, Image 21).

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Comparisons with other data

Also on record for this site: Necker Island, BVI — circumnavigated over six dives/swims, 1-2 Jul 2026: Red Dock, Turtle Beach (×3 visits), Bali Hai-to-Turtle-Beach and Watersport-Beach-to-Bali-Hai transects. Click to expand individual sites (positions approximate, refined GPS to come).

Other notes

Reviewed all 55 frames. Twelve are topside or at-surface: the Red Dock pergola and pink jetty, the catamaran beach under a thick sargassum wrack line, Turtle Beach, and sand spits looking across to Virgin Gorda. Pale cream Porites finger clumps sprout from turf-covered massive mounds; mustard-yellow Porites astreoides lobes recur, repeatedly with pink coralline algae overgrowing dead margins (e.g., Image 13, Image 16, Image 26, Image 34). Coral cover for this site is 14.3% - a CoralSCOP computer vision photographic index over 121 frames, not a diver transect, and worth weighing against what the frames show: this reef is full of coral-shaped dead skeleton (e.g., Image 4, Image 5, Image 20).

Also on record for this site: Necker Island, BVI — circumnavigated over six dives/swims, 1-2 Jul 2026: Red Dock, Turtle Beach (×3 visits), Bali Hai-to-Turtle-Beach and Watersport-Beach-to-Bali-Hai transects.