Coral Reef Diagnostics

St. Eustatius - The Ledge to Hangover

Reef Check Foundation
⬇ Download this page as a report card

Part of the regional summary: St. Eustatius

More about this place: Sint Eustatius on Wikipedia

05
Coral Health Index: TBD
Photo: Anderson Mayfield/Coral Reef Diagnostics
Country
St. Eustatius
Survey date(s)
2026-02-24
Coordinates
17.4635, -62.9838
Approximate position.
Coral cover
2.9%
Claude computer vision (88 photos) · other methods below · median 0.0%
Observations
None tagged; see Stressors below
Heat stress
Most recent heat load record
29.7°C12.9°C-weeks
26 Oct 2026 · Alert Level 2
5-year thermal stress load
5-year mean max. degree heating weeks (DHW)
13.9°C-weeksi
2021–2025
NOAA Coral Reef Watch — Leeward Caribbean Islands virtual station
i 5-year mean max. DHW is the mean of the annual maximum DHWs over the five complete years named above, not conditions today.
More infoLeeward Caribbean Islands (NOAA CRW virtual station)
Photographs
95
48 shown on this page
Site summary
Read this summary in:

Low, gorgonian-carpeted pavement stepping down to a 1.5-2 m undercut ledge (the "Hangover"), where a great barracuda rests and snapper school beneath the overhang. Sea fans and giant barrel sponges dominate, while stony corals are small and scattered; one massive colony shows a band of freshly exposed skeleton, a tissue-loss lesion consistent with stony coral tissue loss disease (SCTLD).

Max. depth dived
21.1 m
dive-log maximum
Water temp. during survey
26.5°C
-1.6°C vs the 12 months to 2026-08 mean sea temperature (28.1°C)

Six independent survey stations shown with the program’s logo — click one to see how far it is from this site.

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

These are unedited originals; edited versions will replace them.

47 of the 48 photographs on this page are shown beside the text that discusses them under "Site description" below.

13

Photo credit & attribution

Site description

General benthic features

Across all 95 unedited frames the habitat is a bioeroded coralline-algal pavement of rounded mounds cut by white sand grooves, stepping down at one point into a distinct vertical ledge 1.5-2 m high with a sand-floored undercut beneath it — the "Hangover" (e.g., Image 2, Image 12, Image 16, Image 20, Image 22, Image 45).

2Image 212Image 1216Image 1620Image 2022Image 2245Image 45

Gorgonians, not corals, build the visual structure: sea fans Gorgonia ventalina in dense stands, feathery sea plumes Antillogorgia, thick sea rods (Eunicea, Plexaurella, Pseudoplexaura), dark Plexaura-type rods, a black sea fan Iciligorgia, and whip-like wire coral (e.g., Image 4, Image 7, Image 8, Image 9, Image 17, Image 19, Image 23, Image 24, Image 25, Image 26, Image 34, Image 43, Image 46, Image 48).

4Image 47Image 78Image 89Image 917Image 1719Image 1923Image 2324Image 2425Image 2526Image 2634Image 3443Image 4346Image 4648Image 48

Sponges are the other dominant: giant barrel sponges Xestospongia muta recur in almost every wide frame, with brown tube and vase sponges (Agelas conifera), orange elephant-ear (Agelas clathrodes), maroon rope sponges (Aplysina cauliformis), pink-brown vase sponges (Niphates), orange ball sponges, and extensive blood-red to maroon encrusting sheets (e.g., Image 1, Image 6, Image 10, Image 11, Image 14, Image 18, Image 21, Image 28, Image 30, Image 32, Image 35, Image 36, Image 44, Image 49).

1Image 16Image 610Image 1011Image 1114Image 1418Image 1821Image 2128Image 2830Image 3032Image 3235Image 3536Image 3644Image 4449Image 49

One barrel sponge hosts an epizoic olive sponge inside its cavity and another shelters a stout reef crab (e.g., Image 3).

3Image 3

Stony corals are small, scattered and dominated by brain corals: Pseudodiploria strigosa appears repeatedly as isolated domes and free-lying plates, with grooved-brain Diploria labyrinthiformis, plating Orbicella/Montastraea, olive foliose Agaricia, and small Porites astreoides, Porites porites, and Siderastrea (e.g., Image 33, Image 39, Image 40, Image 47).

33Image 3339Image 3940Image 4047Image 47

Bare gorgonian axes recur, and macroalgae plus turf cover much of the pavement (e.g., Image 27).

27Image 27

Coral cover

Stressors

One frame shows a massive colony with a bright white band of freshly exposed skeleton beside a sediment-covered dead center — a tissue-loss lesion consistent with stony coral tissue loss disease (SCTLD) (e.g., Image 37).

37Image 37

Fish and other fauna

A Nassau grouper, great barracuda resting under the ledge, a schoolmaster snapper school tucked into the overhang, porcupinefish, a large indistinct fish deep in the undercut, Bermuda chub, stoplight parrotfish, Spanish hogfish, blue tang, blue and purple chromis, fairy basslets, a flamingo tongue snail Cyphoma gibbosum on a gorgonian branch, and a live queen conch photographed eye-to-eye (e.g., Image 5, Image 29, Image 31, Image 38, Image 41, Image 50).

5Image 529Image 2931Image 3138Image 3841Image 4150Image 50

Comparisons with other data

Hoeksema et al. (2022) surveyed a nearby station (The Ledge I), 0.09 km from the pin. Within 5 km, six independent stations (Reef Check and XL Catlin Seaview Survey) recorded station-year means of 0.7–38% hard coral cover between 2005 and 2013; the nearest of these, Reef Check at Mushroom Garden Line 1, 0.67 km away, read 9.4–33% between 2005 and 2009.

Dive record

Dived as the second dive of 24 Feb 2026, descending a mooring line through clear blue water onto low-relief reef.

CV model comparison

Mean 2.9%, median 0.0% across 88 photos.
More infoA few colony-focused photos raise the mean; the median is the typical photo. No computer-vision method yet estimates coral cover accurately on new images, so treat this as indicative rather than a measurement; it is revised as the methods improve.
Headline: Claude computer vision — a blind point count of this site's own photographs.
More infoDINOv3 and CoralSCOP were run on the same photos and are listed for comparison. No diver transect exists for this trip, so agreement between the rows is not accuracy, and no computer-vision method yet estimates coral cover accurately on new images; treat every row as indicative.
MethodHard coral cover (%)Photos (n) ± SE
In-house DINOv317.0n = 88 · SE 0.7
CoralSCOP unedited25.8n = 88 · SE 1.5
Claude2.9n = 88 · SE 0.6

The two computer-vision methods differ by 8.8 pp (17.0–25.8%) and read 14.1–22.9 pp above Claude's blind point count (2.9%); the headline is Claude's blind point count because no transect or manual count exists here.

See a more detailed, stand-alone version of this table.

Independent surveys nearby

Data availability near this site
Agency / programYear(s)Stations / distanceLink
Reef Check2005–20104 stations, 0.67–0.84 kmRecords ↓
XL Catlin Seaview Survey20132 stations, 1.07–1.16 kmRecords ↓
Hard coral cover over time — this site and every independent station within 5 km. Programs are shown separately because they use different methods at different stations; the lines are not one comparable series.
0%10%20%30%40%200520152026Reef Check 2005: 24%Reef Check 2005: 25%Reef Check 2005: 28%Reef Check 2005: 29%Reef Check 2007: 11%Reef Check 2007: 24%Reef Check 2007: 33%Reef Check 2007: 38%Reef Check 2008: 11%Reef Check 2008: 16%Reef Check 2009: 9.4%Reef Check 2009: 22%Reef Check 2010: 26%XL Catlin Seaview Survey 2013: 0.7%XL Catlin Seaview Survey 2013: 2.0%Coral Reef Diagnostics 2026: 2.9%Year-averaged across all programs: illustrative only; the programs differ in stations and method, so no trend is claimed (7 years)
Reef Check XL Catlin Seaview Survey Coral Reef DiagnosticsYear-average (illustrative only, programs differ)

Within 5 km, 6 independent survey stations recorded hard coral cover in 16 surveys between 2005 and 2013. Of the 4 stations surveyed in more than one year, 3 declined (by 1.0–20 points) and 1 increased (by 14 points) between their first and latest surveys. The longest record, Barracuda Reef Line 1 (Reef Check, 0.84 km away), went from 28% in 2005 to 26% in 2010 (mean of 2 surveys). The most recent nearby survey is from 2013, so these values predate recent heat stress. This site's own estimate (2.9%) sits within the range of these station-year means (0.7–38%); the methods differ, so the comparison is context, not a like-for-like test.

Collected by other programs using different methods (Reef Check uses point-intercept transects; the XL Catlin Seaview Survey uses photo-transects with automated image annotation), so these are context for the figures above, not a like-for-like comparison. Where a station was surveyed more than once, the cell shows either the range of its values or, as a single value, the mean of surveys made in one year. Station names are not dive-site names.

Independent survey data near this site
AgencySite / locationDateHard coral cover (%)DistanceLink
Reef CheckMushroom Garden Line 12005–20099.4–33% (4 surveys)0.67 km—
Reef CheckMushroom Garden Line 22005–200724–38% (2 surveys)0.67 km—
Reef CheckBarracuda Reef Line 12005–201011–28% (range of yearly means; 6 surveys)0.84 km—
Reef CheckBarracuda Reef Line 22005–200724–25% (2 surveys)0.84 km—
XL Catlin Seaview Surveytransect 2501620130.7%1.07 kmdoi:10.14264/uql.2019.930
XL Catlin Seaview Surveytransect 2501520132.0%1.16 kmdoi:10.14264/uql.2019.930

Data & links

All images from Coral Reef Diagnostics. Data are from Coral Reef Diagnostics and the organizations named in the data sources above.

© Coral Reef Diagnostics.

References

  1. Hoeksema BW, van der Loos LM, van Moorsel GWNM (2022). Coral diversity matches marine park zonation but not economic value of coral reef sites at St. Eustatius, eastern Caribbean. Journal of Environmental Management 320:115829. DOI
  2. Gonzalez-Rivero M, et al. (2019). Seaview Survey photo-quadrat and image classification dataset. The University of Queensland (UQ eSpace) data collection. DOI