Coral Reef Diagnostics

Red Dock

Virgin Limited Edition — Necker Island

← BVI - Necker Island

05
Coral Reef Diagnostics
Photo: Anderson Mayfield/Coral Reef Diagnostics
Survey date(s)
2026-07-01
Coordinates
18.5252, -64.3525
midpoint of a 1,122 m transect — see the map below
% coral cover
7.4%
Manual point count by the author (35 hand-scored photographs)
Photographs
93
Site summary

Red Dock is the shallow reef off Necker Island's pink jetty, where living elkhorn coral, a threatened Caribbean species, still forms broad golden stands beside the skeletons of colonies lost earlier. Boulder and brain corals, finger-coral thickets, and sea fans fill in, and hand-counted photos put living hard coral at 7.4%. No bleaching or disease was seen.

Observations
recent mortality

The white line is this site’s dive track — the white dot marks where it started and the red “End” marker where it ended.

Three other CRD dive sites with their own pages within 5 km shown in orange — click a marker to open its page.

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Site description

Anderson's own point count of 35 Red Dock photographs (1,050 points) puts hard coral cover at 7.4% ± 11 (median 4.0, range 0–47%). Massive heads on pavement (22 frames) are the commonest habitat — Orbicella annularis-complex and Porites astreoides lobes, many largely turfed with live tissue reduced to patches. Living elkhorn (9 frames) is the finding that matters: broad Acropora palmata plates with white growing margins, in thickets and as isolated colonies. Red Dock is the only Necker area with manual ground truth; computer-vision values are listed in the method table for comparison.

Stressors

One live elkhorn-type colony at Red Dock has a sharply bordered patch of recently exposed white skeleton at its center, between pigmented branches: recent partial mortality, cause not stated.

CV model comparison

MethodHard coral cover (%)
Manual point count (headline, 35 photos)7.4
Claude (87 photos)8.0
Claude (same 35 photos as the manual count)6.7
In-house DINOv320.2
CoralSCOP20.8

Manual = Anderson's own point count of 35 Red Dock photographs; the computer-vision values, Claude included, are for comparison.

All images from Coral Reef Diagnostics. Data are from Coral Reef Diagnostics.

© Coral Reef Diagnostics.