Mauritius - Lost Anchor
Part of the regional summary: Mauritius
More info
Southern Mauritius (NOAA CRW virtual station)A low-relief boulder field off Coin de Mire in northern Mauritius, where most surfaces are turf and coralline crust rather than living coral. It is punctuated by a stand of large sea fans and a lone healthy staghorn thicket on sand, with a whitemouth moray and a camouflaged octopus among the sightings.
Un champ de blocs à faible relief au large du Coin de Mire, dans le nord de Maurice, où la plupart des surfaces portent du gazon algal et des croûtes corallines plutôt que du corail vivant. Il est ponctué d'un ensemble de grandes gorgones et d'un unique massif d'acropores branchus en bonne santé sur le sable ; une murène à bouche blanche et un poulpe camouflé comptent parmi les observations.
Traduction par IA de ce résumé ; la version anglaise fait foi.
Five independent survey stations shown with the program’s logo — click one to see how far it is from this site.
One other CRD dive site within 5 km shown in orange — click a marker to open its page.
10 of these 50 photographs are shown beside the text that discusses them under "Site description" below.
Site description
General benthic features
Lost Anchor (Coin de Mire) is a low-relief boulder field: turf- and coralline-encrusted boulders and dead reef framework cut by sand and rubble channels, with manually scored point-count cover of 11% hard coral (e.g., Image 4, Image 5, Image 9, Image 17).
Live colonies are mostly small lavender Pocillopora and massive Porites, punctuated by a stand of large gorgonian sea fans and a lone healthy staghorn Acropora thicket on sand (e.g., Image 1, Image 2, Image 3, Image 13).
Coral cover
Coral cover: 10% — the site cover estimate from Anderson Mayfield's Mauritius manuscript (his manual point count and CoralNet, weighted equally); the manual point count alone is 10%. The earlier four-method average for this site was 15.3%; every method is compared in the table below. The methods have different denominators and sampling footprints, so this is a provisional photo-derived index rather than a diver survey, and the agreement between the four is the real measure of confidence at this site. Anderson keeps an eye out for newer CV models and will refresh this CoralSCOP and DINOv3 figure once a more trustworthy option is available.
Stressors
No crown-of-thorns starfish (COTS) or other corallivores evident.
Fish and other fauna
Notable sightings included a whitemouth moray, a probable camouflaged octopus, Diadema-type urchins, and dense clouds of chromis and damselfish; no widespread bleaching was evident (e.g., Image 12, Image 16).
Comparisons with other data
No independent survey was made at this exact site; the nearest ones are listed in the table below.
CV model comparison
More info
The settled rule would raise every Mauritius site by 0–3.7 pp. Awaiting Anderson's ruling. The Claude row is the manuscript's Claude (with image context) value, scored on the same manual-reference frames as the manual count (v42 Table 3); the last of its five context batches had been seen before, so it is not fully blind. Anemone Garden is flagged non-reef in the source (anemone habitat); its manual value stands but carries no error term. CoralSCOP (SAM-based mask-sum), edited photos: n/a — no edited copies exist; EDITED_UNEDITED_RULES.md records Mauritius as verified 347/347 unedited| Method | Hard-coral cover (%) |
|---|---|
| Site cover estimate | 10.2 |
| Manual (draft manuscript) | 10.5 |
| CoralNet | 10.0 |
| In-house DINOv3 | 20.3 |
| CoralSCOP unedited | 20.5 |
| Claude | 9.2 |
Independent surveys nearby
| Agency / program | Year(s) | Stations / distance | Link |
|---|---|---|---|
| Original collectors (compiled by McClanahan et al. 2016) | 2016 | 2 stations, 3.59–3.64 km | Records ↓ |
| Reef Check | 1999 | 1 station, 3.06 km | Records ↓ |
| WCS Kenya / University of Mauritius via MERMAID | 2019 | 1 station, 0.27 km | Records ↓ |
| WCS via MERMAID | 2016 | 1 station, 4.86 km | Records ↓ |
Dr. Coral (CRD)Year-average (no detectable trend)Within 5 km, 5 independent survey stations recorded hard coral cover in 7 records between 1999 and 2019. The most recent nearby survey is from 2019, so these values predate recent heat stress. This site's own estimate (10%) sits within the range of these surveys (10–46%, excluding 3 best-patch values above 70% that are not a site mean); 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; MERMAID is a data platform: each MERMAID row names the organization that did the survey, and its method is in the row's hover text), so these are context for the figures above, not a like-for-like comparison. Where a station was surveyed more than once the range is shown. Station names are not dive-site names. Values marked best patch exceed 70%: surveyors usually chose the richest area, so they are not site means.
| Agency | Site / location | Date | Hard coral cover (%) | Distance | Link |
|---|---|---|---|---|---|
| Reef Check | Island Reef, Anse La Raie | 1999 | 46% | 3.06 km | — |
| Original collectors (compiled by McClanahan et al. 2016) | ALR/ALBC (Mauritius) | 2016 | 89% best patch | 3.59 km | — |
| Original collectors (compiled by McClanahan et al. 2016) | ALR/ALLC (Mauritius) | 2016 | 98% best patch | 3.64 km | — |
| WCS via MERMAID | Bain Boeuf | 2016 | 71% (2 images) best patch | 4.86 km | Briand J, Darling E. 2016. 2016 bleaching surveys. MERMAID |
| WCS Kenya / University of Mauritius via MERMAID | Coin de Mire | 2019 | 10% (2 images) | 0.27 km | Darling E, McClanahan T, Muthiga N. 2019. Mauritius 2019-2020. MERMAID |
Data & links
- CoralNet image repository for this region ↗
- Photo portfolio ↗
- Coral Reef Diagnostics page for this area ↗
All images from Coral Reef Diagnostics. Data are from Coral Reef Diagnostics and the organizations named in the data-sources table above.
© Coral Reef Diagnostics.