St. Regis Vommuli

Reefscapers at St Regis Maldives

Coral paling, fluorescing, and bleaching on our Reefscapers coral frames at our ‘Adopt-A-Coral’ site

During May, we created 5 new coral frames of various sizes. A total of 5 coral frames were checked as part of our 6-monthly monitoring, involving cleaning and repairing, and uploading new photographs to our website for our kind sponsors 🙏  In total, we conducted 20 maintenance visits, and inspected all 190 of our coral frames around Vommuli.

To see the progress of your frame, please visit our dedicated St Regis monitoring page where we upload new photos every 6 months or so. You can Sponsor your very own complete coral frame, or Adopt a community-frame coral fragment here.

🪸Dive Centre Site – Although this site is one of our deepest (at an average 4.5m depth) coral paling of our coral frames was observed here first, caused by the seasonally elevated sea surface temperatures (SST). By the first week of May, ~70% of the frames presented bleaching, especially the branching species (although both Acropora digitifera and A. humilis remain healthy so far). In addition to the high temperatures, the seasonal monsoon storms and strong ocean currents also affected this site. Many frames were dislodged, and some had even been flipped over by the ocean turbulence. During our maintenance visits, the frames were uprighted and repaired. In addition, we have sadly observed wild mature table corals with 100% bleaching levels, all the way down to depths of 20m.

🪸 Adopt-A-Coral Site – This site was the last to start showing signs of coral bleaching. Macroalgae has started growing on ~15% of the fully bleached frames, although only the very newest frames have died so far. Acropora digitifera has shown to be the most resilient, with most (65%) of the colonies remaining healthy:
Bleaching surveys for Acropora digitifera on our coral frames: Pale: 20% / Bleached: 15% / Healthy: 65%
The plentiful wild colonies of A.digitifera around the island are also bleaching, including the House Reef table colonies, with some mortality by the end of the month. Some good news is that the largest (4m wide) wild Porites colony at this site is still healthy. The ‘massive’ species of corals are known 

🪸 Whale Bar Site – Mature coral frames are paling at this site, and our newest frames exhibited a high mortality rate. The wild House Reef, close to the Water Villas, has been our healthiest and most biodiverse reef, but is worryingly showing a high percentage of both bleaching and mortality down to 8m depth.

Reefscapers at St Regis Maldives

🎙️ Marine Talks – A total of 4 sessions were given for the Evening Talks (8 guests), and we also held 6 sessions at the kids club for the “Shark Yoga” and “Sea turtle beach” with 16 children participating. In addition, with the support of Sustainable Ocean Alliance, 16 teenagers studying tourism in Ecuador received a virtual session about coral reef awareness and sustainable tourism.

🤿 Marine Biology Excursions – During May, we conducted 3 dolphin cruises, one coral garden, and one turtle quest excursion for a total of 31 enthusiastic guests. We logged our megafauna sightings, including numerous blacktip and white tip reef sharks.

⏯️ Social media – Three of our St Regis reels posted on Reefscapers instagram proved very popular, totalling more than 300K views!

Sheraton Full Moon

Reefscapers at Sheraton Maldives blacktip

During May, we built 12 new coral frames, out-planted at 11m depth at the Boat Garden site. In addition, we monitored (cleaned, repaired, photographed) a total of 23 coral frames at our Water Villas site. The routine monitoring of our frames has been paused due to the ongoing coral bleaching event (caused by the current marine heatwave). We continue to monitor for bleaching and mortality (see below), but we are not adding/recycling new coral fragments as they are particularly vulnerable to heat stress.

To see the progress of your frame, please visit our dedicated Sheraton monitoring page where we upload new photos every 6 months or so.

Coral Propagation Sites

Summary of our reef regeneration sites around the island. We have paused all recycling work until the ocean temperatures have returned to normal.

  • Blue Hole – coral bleaching at this site is becoming more severe, and we are starting to see some mortality of our coral frame colonies. Most of the colonies remain alive, but are highly stressed (bleaching and fluorescing). Some maintenance work has started to remove the dead colonies, and we have been lifting some frames due to sand movement.
  • Water Villas – coral bleaching is increasing, and we are seeing some high levels of mortality in newly transplanted frames (more vulnerable to heat stress). Most Acropora colonies are bleached, but show low mortality so far.
  • Dive Centre & Boat Garden – frames around the pyramids are bleaching, and there is some mortality. The boat garden frames (at 10-12m depth) are still looking healthy, with very few colonies paling. We will continue outplanting new frames at this site.
  • Dive Centre Pyramids – some coral mortality, particularly in large colonies of Acropora cytherea. Interestingly, some colonies are already starting to show signs of recovery, plus some lower more-shaded colonies on the under side of the pyramids remain healthy.
  • Lagoon Pyramids – significant mortality as we expected, due to the stillness of the lagoon and higher temperatures at this site. Significant maintenance will be required to remove the dead colonies and re-space the healthy ones.
Reefscapers at Sheraton Maldives water villas (1-2m)

Progression of coral bleaching at our ‘Water villas’ site (1-2m)

Reefscapers at Sheraton Maldives blue hole (3m)

Progression of coral bleaching at our ‘Blue Hole’ site (3m deep)

Coral Bleaching Monitoring

Bleaching score key: (1) No bleaching, (2) 1-10% of colony bleaching, (3) 11-50% bleaching, (4) 51-99% bleaching, (5) 100% bleached, (6) Dead.

Bleaching surveys were conducted twice in May, in the first and the second half of the month. The majority of Acropora species are showing average bleaching scores around 5 (100% bleached). In some species (eg: A.hemprichii, A.tenuis) the rate of bleaching has slowed throughout May, and some species (eg: A.digitifera) are averaging lower scores than the other species within the genus.
Pocillopora corals are overall much healthier than Acropora, with average bleaching scores between 1 and 2 (0-10% bleached).
This month, we have seen a progression of coral bleaching averages from around 4, to closer to 5-6, as the degree heating weeks accumulate. We have also just started to record high levels of mortality in some sites.

Coral frame bleaching (Mar-May 2024)

Composite image to show coral bleaching on a single frame (Mar/May)

Coral frame bleaching (Mar-May 2024)

Composite image to show coral bleaching on a single frame (Mar/May)

Bleaching by Site

Bleaching has been widespread in Acropora species across our main sites: Dive Centre, Blue Hole, and Water Villas. On average, the bleaching scores appear lower at the Dive Centre (coral pyramids). Similarly, frames at the Blue Hole site are slightly healthier than the Water Villas frames. This trend correlates with the depth of each site, as the frames at the Water Villas are the most shallow, and the pyramids at the Dive Centre are the deepest. During this vulnerable period for corals, we are closely monitoring for aggressive corallivores (Drupella snails, and crown of thorns starfish) but thankfully we have not seen any so far.

Reefscapers at Sheraton Maldives coral bleaching transects

We analysed the data from our survey monitoring of over 1,000 coral colonies across all sites around the island. Only those species with data for 10+ colonies were included.
Average bleaching scores from the first, third, and fifth surveys of bleaching, conducted in: (1) early March, (2) late April, (3) late May.

Reefscapers at Sheraton Maldives bleaching A.muricata

Bleaching Acropora muricata

Coral Spawning & Gametogenesis

New Moon period – our night-snorkelling checks identified one colony of A. tenuis spawning (which had also spawned in April). Some checks had to be cancelled due to stormy weather and rough seas.

Full Moon period – checks were not possible due to bad weather.

Research Submissions

This month, we successfully submitted our second research paper to a scientific journal, “Environmental Factors Influencing Acropora Coral Spawning Timing and Synchronicity Across Two Maldivian Atolls”. We hope this paper will be accepted for publication, thereby advancing Reefscapers’ contributions to this field of coral sexual reproduction, and increasing our research output from here at Sheraton Maldives. (More info on our historical research.)

Marine Life

🤿 Snorkelling Excursions – Our ‘Maldivian Journey’ snorkelling trips were attended by a total of 20 guests, averaging ~80 minutes duration. Blacktip reef sharks and hawksbill turtles were seen on multiple trips. Spotted eagle rays were seen around our island, along with green turtles at the sea grass patch. Overall, turtle sightings are much higher in the first five months of 2024 than in 2023.
Snorkelling Safaris to nearby reefs recorded regular sightings of stingrays, and one excursion was lucky to sight a juvenile whaleshark! This is rare for North Malé Atoll, but sadly the whale shark had a dorsal fin injury, likely from boat damage.

🐬 Dolphin Cruises – Spinners were sighted during both trips this month, but no other species were recorded.

🎙️ Marine Talks – a total of 13 guests attended our 6 talks this month, averaging ~40 minutes duration. Numbers were down due to the low tourist season and stormy weather conditions.