Mauritius - Anemone Garden

Setting

Not a coral reef but a true anemone garden: large bommies on a sand-and-algae lagoon flat carpeted nearly wholesale by magnificent-type sea anemones (consistent with Heteractis magnifica), attended by clouds of dark Dascyllus-type damselfish (e.g., Image 3, Image 11, Image 12, Image 13, Image 14, Image 16).

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Coral cover

• Reference: Mayfield et al. (2026, Platax), Table 3 (manuscript in preparation)
• CoralNet submission package
• Manually scored hard coral cover was just 2.7%, limited to scattered small branching and massive dome-shaped colonies (e.g., Image 4, Image 7, Image 18).
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• No error terms are given, since neither CoralSCOP nor DINOv3 could reliably distinguish anemones from scleractinian corals.
• Both models have known weaknesses, and they are different weaknesses.
• CoralSCOP computer vision reads HIGH on low-cover reefs: across twelve sites with a Reef Check diver survey within 1 km, the median CoralSCOP figure is 1.68x the survey value and the worst case is 4.6x.
• The DINOv3 point classifier is strong on reefs resembling its training data (6-class macro-F1 0.62, hard coral recall 0.82) but degrades badly on an unseen reef — cross-domain point accuracy measured at 0.17-0.25 against Anderson Mayfield's own annotations, with a documented ceiling near 35-50%.
• Neither is a diver survey, neither is a benthic transect, and both should be read as provisional indices that a better model would supersede.

Stressors

No widespread bleaching was evident. Two sea anemones were bleached, one with white to faintly pink-cream tentacles (e.g., Image 16) and one with stark-white tentacles over a dark red column (e.g., Image 51), among tan, orange, and pink neighbors.

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Fish and other fauna

Highlights included a trumpetfish, honeycomb grouper, whitemouth moray, longfin bannerfish, spiny cushion stars, and sea cucumbers (e.g., Image 1, Image 2, Image 10, Image 17).

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Comparisons with other data

WCS Kenya / University of Mauritius surveyed a nearby station (Anenome/Mahebourg) in 2019, 0.04 km from the pin (data via MERMAID). Within 5 km, two independent stations (WCS Kenya / University of Mauritius via MERMAID and WCS via MERMAID) recorded station-year means of 18–73% hard coral cover between 2016 and 2019, all with MERMAID bleaching-protocol quadrats; the nearest, WCS Kenya / University of Mauritius via MERMAID (quadrats) at Anenome/Mahebourg, 0.04 km away, read 18% in 2019.