Saba - Ladder Labyrinth

Setting

A maze of boulder-strewn rock ridges separated by narrow sand channels, matching the site's "Labyrinth" name directly: one frame looks straight down a sandy corridor flanked by two rock walls, a whitetip/nurse shark's silhouette visible resting on the sand ahead, and a second frame shows the same or a similar nurse shark (Ginglymostoma cirratum, confirmed by its rounded snout and barbels) resting tucked under a rock ledge (e.g., Image 14, Image 20, Image 45).

142045

Visibility is good to excellent throughout, with strong ambient blue light in the open-water frames.

General benthic features

Coral cover on the ridges is real but patchy and small-colony: scattered knobby/lobed star-coral heads (olive-green, several photographed in clusters of three to five small colonies on a single boulder), a scoop-shaped mustard-hill or star coral, and one notably large, pale, evenly-ridged meandroid/star coral colony photographed close-up under blue ambient light -- its tissue reads unusually pale/whitish, which may reflect a lighting/white-balance effect from strobe-free blue water rather than true bleaching, but is different enough from the other, clearly healthy olive-brown colonies in this sample to flag (e.g., Image 26, Image 27, Image 28, Image 34, Image 43).

2627283443

Sponges and octocorals recur throughout: mustard-yellow tube sponges, orange encrusting sponges, a purple sea fan, black sea rods, and a delicate pale gorgonian branching from a crevice (e.g., Image 4, Image 44, Image 50).

44450

Coral cover

Coral cover: 8.9% — a blind Claude computer-vision point count of 82 of Anderson's unedited photographs (20 points per photo; water, fish, and obstructions excluded). Other computer-vision methods are listed in the method table. Frames were screened before scoring: open sand, mid-water, blown-out, and burst-duplicate frames, dive computers, topside, and diver shots, blue-light fluorescence, and macros were all removed.

Stressors

No disease or physical damage is visible on any of the small star-coral colonies reviewed. No corallivores evident.

Fish and other fauna

Reef fish include blue and brown chromis, sergeant majors, and a school of two crevalle/horse-eye jacks cruising in open blue water off the structure (e.g., Image 9, Image 19).

919

Comparisons with other data

Also on record for this site: Boulder and brain corals (some fluorescing bright blue/green under lights) top the boulders alongside barrel sponges and sea fans, with an old fish trap wedged in the sand (e.g., Image 30, Image 41, Image 49).

304149

Multiple nurse sharks rested in the sandy alleys, plus a spiny lobster under a ledge, schools of blue chromis/creole wrasse, and jacks in the blue (e.g., Image 23).

23