Kenya - Lower Mpunguti-site 1 (Kisite National Park)

General benthic features

The loudest signal in the set is algae, not bleaching, and the full run of frames makes the case strongly. Fleshy macroalgae — rust-red and olive foliose fronds, brown Sargassum- and Dictyota-like blades, and green Halimeda-type tufts — blanket the hardground in nearly every wide frame. In several frames the macroalgae are overgrowing coral colonies, overtopping a white branching colony and a meandroid colony. Anderson photographed it specifically in two frames: one is a reef mound almost wholly upholstered in weed with only two white coral heads showing through, and the other is a single bleached branching colony ringed and half-buried by canopy (e.g., Image 3, Image 4).

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Coral here is not a framework; it is isolated colonies set into an algal carpet, which reads as the physical expression of the site's 18% cover.

Coral cover

• Reference: Mayfield (2025)
• Data file: (Mayfield, 2025-Supplemental File S1)
• CoralNet submission package (accession #4963)
• Coral cover 18% — and 80% of hard coral tissue bleached (March-April 2024).
• Measured from 36 white-balanced photographs taken at this site during the 2024 Western Indian Ocean mass bleaching event and point-annotated in CoralNet, published in Mayfield, A.B. (2025) A Citizen Science Approach for Documenting Mass Coral Bleaching in the Western Indian Ocean. Environments 12(8):276. doi:10.3390/environments12080276.
• This is a published diver-photograph point-annotation value, not a computer vision estimate.
• Across the 20 Kenyan sites the mean was 30% coral cover and 77% of tissue bleached.

Stressors

Bleaching is extensive but not uniform, and it sorts by growth form. Branching and corymbose Acropora are the worst hit: stark bone-white thickets in six frames (one a broad fine-branched stand gone entirely white, with a second white colony below it), with a few colonies tinged pale lilac-blue rather than pure white in two others. Massive and domed colonies are close behind: chalk-white domes with dark fissures in two frames, a bone-white knobby columnar colony standing proud of the reef with a crinoid at its base in another, and a cluster of white massives over sand in a fourth (e.g., Image 1).

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Anderson's own named frames add two more: one is a pale cream Astreopora dome set in macroalgae, and the other is a white-to-pale-gray digitate finger Porites colony ringed by weed. One frame is a mauve-pink encrusting mass — the intermediate paling tone rather than full white — and another is a pale blue-gray meandroid brain coral with its valleys still sharply defined, emerging from a thicket of brown fronds. The last frame of the dive is a large smooth-lobed chalk-white mass on the sand, most consistent with a bleached leather soft coral (Sarcophyton-type); a pale sponge cannot be excluded from the frame alone. Against that, the foliose cup and plate corals are the clear survivors, and across the full set this is a repeated pattern rather than a single refugium. Turbinaria-type bowls appear fully pigmented golden-olive to tan in four frames, including a top-down stack of tiered bowls with fine concentric growth lines and a large healthy cabbage-form colony — and one of them shows a small pufferfish tucked down inside the bowl (e.g., Image 2).

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Two frames are broad tan-brown foliose plates whose only whitening is a narrow band along the growing margin, which on these color-adjusted frames could as easily be the normal pale growth edge as a bleaching front. The one foliose colony that does look genuinely bleached is a large stacked whorl-form plate gone uniformly pale cream on an algal ridge. One frame places a bleached white Acropora directly against a large tan barrel sponge on the rubble. Typical recent thermal stress: mean annual maximum of 4.9 degree heating weeks (2021-2025, NOAA CRW; Kenya virtual station). Seawater here was an estimated 31.9°C during the survey (read from the TG7 underwater camera and not validated, per Mayfield 2025, Environments 12:276, Table 1; the Kenya survey-wide mean of 32.0°C matched the 1998 event), and NOAA recorded a peak of 13.5 degree-heating weeks on 18 April 2024, the highest for Kenya since records began in 1985. For the 2024 Kenya survey as a whole, Mayfield (2025, Environments 12:276) estimated that in situ temperatures ran about 1.3°C above NOAA's, so that "nearly 22 DHWs may actually have transpired"; those in situ readings came from the TG7 underwater camera and have not been validated. No crown-of-thorns starfish (COTS) or other corallivores were evident.

Fish and other fauna

One cluster, which Anderson recorded as a bleached anemone, is three magnificent sea anemones with tentacles blanched snow-white above deep crimson-magenta columns, packed together on the rock. Elsewhere a blue-spotted ribbontail ray sits under a ledge on clean sand beside pale coral heads. Two giant clams (Tridacna) sit side by side with fluted mantles still patterned brown-gold and olive, no whitening, among crinoids and orange encrusting sponge. A red-and-white striped squirrelfish rests against a bone-white dome, and an orange encrusting sponge is worked over by small damselfish. A pale mauve-white sea cucumber lies on the sand, and a sand channel runs beneath an algal-crusted overhang with almost no coral in it.

Comparisons with other data

REEFolution Foundation surveyed a station named Lower Mpunguti, 0.69 km away. Within 5 km, 24 independent stations recorded hard coral cover between 2008 and 2024: nine by benthic survey, station-year means of 0.0–66%, and fifteen by MERMAID bleaching-protocol quadrats, station-year means of 18–56%; the nearest, REEFolution Foundation at Lower Mpunguti, 0.69 km away, read 0.0–8.0% between 2017 and 2019.

Dive record

Dived 21 Mar 2024 off Lower Mpunguti in Kisite Marine National Park, during the 2024 Western Indian Ocean mass bleaching event. EXIF on the 34 reviewed frames (of 36 on file) dates every one to 21 March 2024 and brackets the photographic run between 13:20:04 and 13:35:14, a tight fifteen-minute sequence, essentially contiguous in camera numbering. Surveys were run with REEFolution.