Oman - Daymaniyat Site 3 snorkel

Setting

Daymaniyat Site 3 is a shallow reef in the Daymaniyat Islands off northern Oman, where hard coral stands rise straight out of brilliant white sand. The water was clear and blue, and the reef is plainly shallow.

General benthic features

Fine-branched tabular and branching hard corals dominated almost every underwater frame, and almost nothing else competed with them for space. The widest view looked down over an unbroken canopy of tiered, overlapping fan- and rosette-shaped tables running away to the top of the frame, thinning at the right edge into clean rippled sand where clouds of small planktivores hung in mid-water (e.g., Image 3).

3

A cropped panorama caught the reef edge head-on: a solid ridge of branching thicket meeting bare white sand in a clean line across the frame (e.g., Image 2).

2

Farther along, the tables formed a continuous field over a gently sloping bottom, cut by winding sand channels and fading into deeper blue water (e.g., Image 16).

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Seen from directly above, the canopy was a dense lattice of stacked plates and fine branches with barely a gap down to the substrate (e.g., Image 19).

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Along the edges of the sand strips, the tables were stacked in overlapping tiers several colonies deep (e.g., Image 14, Image 20).

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Dense canopy, broken only by small sand patches, extended across much of the reef (e.g., Image 10).

10

At colony scale, single isolated tables stood alone on rippled sand, a rosette of fine, open branches in one frame and a broader brown corymbose table with damselfish swarming over it in another, with more thicket in the background of both (e.g., Image 1, Image 4).

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Other stands were built of taller, arborescent branches, forming staghorn-like thickets over the sand, with broken, pale branch rubble scattered on the sand below (e.g., Image 18).

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In another area, a field of compact, knobby corymbose colonies packed shoulder to shoulder in front of the table zone (e.g., Image 13).

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Between the coral stands, the sand was bare, clean, and rippled (e.g., Image 9).

9

Coral cover

• Reference: Mayfield (2025)
• CoralNet submission package
• Published hard coral cover is 33%, from CoralNet point annotation of 28 photographs (Mayfield 2025, Platax, Table 1; 30 points per photo, water and fish excluded).
• A further 43% of points was scored as soft coral. An August 2026 photo review of this site's frames found that most of these soft-coral points fall on tabular hard corals the classifier mislabeled, so the hard coral figure likely understates the true hard coral share.
• The published figure carries the provenance of the paper it appears in and is not subject to the CoralSCOP/DINOv3 caveats applied elsewhere on this map.

Stressors

Very little bleaching was observed during these May 2024 surveys (about 0.02% of coral tissue area; Mayfield 2025), which came before the seasonal SST peak; NOAA CRW recorded Alert Level 2 heat stress and bleaching was reported along this coast from July 2024, weeks after the surveys. No macroalgae, bleached branches, or sediment veneer were seen on the living coral. Mortality was not absent, however: one frame showed a patch of old, dead branching framework that was gray and furred with turf, lying beside living tables (e.g., Image 11).

11

Typical recent thermal stress here is a mean annual maximum of 11.0°C-weeks (Degree Heating Weeks, 2021-2025, NOAA CRW; Gulf of Oman virtual station). No crown-of-thorns starfish (COTS) or other corallivores were evident.

Fish and other fauna

Small damselfish and other planktivores swarmed over the coral in clouds, and a loose shoal hung in mid-water just beneath the surface (e.g., Image 15).

15

Sea cucumbers lay scattered across the sand between the coral stands.

Comparisons with other data

Sultan Qaboos University surveyed a nearby station (Dimaniyat - Turtle City (Deep)), 1.58 km from the pin; we could not confirm that it is the same reef. Within 5 km, seven independent stations (Environment Authority-Oman, Sultan Qaboos University, and submitted to MERMAID by Alhussaini A.) recorded station-year means of 0.0–35% hard coral cover between 2025 and 2026; the nearest, Sultan Qaboos University at Dimaniyat - Turtle City (Deep), 1.58 km away, read 35% in 2026.

Dive record

Anderson snorkeled the site on 25 May 2024, on the Daymaniyat Islands turtle-snorkel trip described in Mayfield (2025, Platax).