Be sure to read our monthly updates from Marine Savers – direct from our teams resident at
the Marine Discovery Centres at Landaa & Kuda Huraa – our long-term partnership with Four Seasons Resorts Maldives.

Landaa Giraavaru

At Landaa this month, we transplanted 20 new coral frames, kindly sponsored by guests (5), the Resort (14), and online (1), adding almost 900 coral fragments to the reef. We monitored (cleaned, repaired, photographed) a total of 315 established coral frames at various sites around Landaa and Voavah.

A total of 20 frames (10 small, 10 medium) were sponsored by a group staying at Landaa, and built in a single day as part of an event held at Voavah. The group engaged enthusiastically with the activity, and we were delighted to see the Voavah reef looking healthy at the time of fragment collection.

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

Research Paper Submission

This month, research documenting the relationship between environmental factors (sea temperature, precipitation, wind speed and tide depth) and spawning patterns of Acropora corals at Landaa Giraavaru and Sheraton resorts was submitted for review.

Maldives Coral Bleaching Season

The ‘summer’ hot season in the Maldives runs from January to May, with March and April being particularly hot and dry. The extra hours of seasonal sunshine, combined with the current elevated global sea surface temperatures (SSTs) cause increased stresses on coral reefs (April-June), which can lead to temporary paling of the coral colonies, or even permanent coral bleaching and death.

Global climatologists are forecasting 2024 to be exceptionally hot, due to a combination of the cyclical El Niño event and the ever-increasing effects of anthropogenic climate change. Over on our Reefscapers Climate Change page, we are following developments very closely by curating the news reports from climate experts and marine scientists worldwide.

Reefscapers coral bleaching survey E14 (April-May)

Coral bleaching survey: colony E14 Bleached / Dead (April / May)

Reefscapers coral bleaching survey E44 (Mar-May)

Coral bleaching survey: colony E44 Healthy – Paling – Bleached
(March – April – May)

Coral Bleaching Watch

Over the last few months we have been tracking NOAA’s coral bleaching watch guidelines. After two months of Baa Atoll being in the “Warning” and “Alert 1” status levels, with the turn of the monsoon we are now at the “Watch” status level. As such, we hope to see some recovery of bleached/pale corals as water temperatures decline.

🗓️ In March, moderate paling was observed in some colonies along Landaa’s House Reef.

🗓️ In April, bleaching and fluorescence was observed at all sites across Landaa from 1m-15m.

🗓️ During May, more widespread bleaching and mortality was observed across all sites around the island, both on the natural reef and our Reefscapers coral frames. As expected, corals of the genus Acropora are bleaching more severely, with colonies in shallow water at the Water Villas and Elephant site being the most affected. Bleaching has also been noted in some Pocillopora and even some massive genera such as Porites.

Photos below – single colony of coral (3 species), shown: ║ Healthy ║ Bleaching ║ Dead ║

Bleaching Monitoring

Following NOAA’s modelled predictions on mass bleaching for this season in the Maldives, we have established a monitoring protocol to assess the impact, extent, and recovery of potential bleaching across our restoration sites at Landaa Giraavaru. This monitoring project should provide an insight into restored coral resilience across sites and species, information that could prove useful towards future frame and species allocation.

We are analysing data percentages of Healthy (codes 4 to 6 on coral health chart scale), Bleached (codes 1 to 3), and Dead colonies at each site. At present, an average of 64% of colonies across the monitored sites have bleached, plus an average of 20% are dead.

🪸 Our Water Villas site has seen a gradual bleaching progression since February, whereas our House Reef site started bleaching in late April; currently, both  sites are similarly affected.
🪸 Anchor Point, our deepest site, presents more resilience than the other sites, although the newer frames are more severely impacted. It’s noteworthy that a few coral colonies at this site (alone) have started to show signs of recovery.
🪸 The Elephant site has been severely affected by bleaching since March, and presents the highest rate of mortality (34%).

Reefscapers coral bleaching survey

Landaa Giraavaru: Results of our coral bleaching surveys so far (end of May). We have 4 different monitoring sites, and the effects of the seasonally elevated ocean temperatures can clearly be seen.
Most corals start off healthy (green), then start to bleach (white); some have already died (black).
Bleached corals can recover if the ocean temperatures soon return to normal (they re-uptake zooxanthellae). But they are vulnerable to predation from corallivorous species (Drupella and COTS). Dead corals quickly become overgrown with algae.

Reefscapers coral bleaching

Kuda Huraa

Acropora millepora coral bleaching Maldives

Close-up of Acropora millepora coral paling and bleaching

At Kuda Huraa this month, we transplanted 6 new coral frames, and monitored a further 80 mature frames at various sites around the island.

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

 

Maldives Coral Bleaching Season

Coral Bleaching

May saw continued bleaching and mortality of corals around Kuda Huraa and the North Malé Atoll. To gain more information on the impact of bleaching in the surrounding areas, we partnered with the Kuda Huraa Dive teams to assess the health of nearby reefs at popular dive sites. So far, we have assessed two sites that were found to be 32% and 40% bleached. With the continued support of Dive, we will aim to survey more sites next month.

On the House Reef, bleaching has reached natural corals at ~14m depth (in the genus Pachyseris), and surprisingly, paling was observed in Mycedium at a depth of ~22m. The deepest occurrence of corals bleaching on our frames is at ~15m (Acropora muricata). This highlights the reach of these high temperatures on the House Reef, and how depth does not always guarantee safety for corals.

As the high temperatures in April continued into May, the shallow corals that bleached last month sadly began to die and become dominated by algae. Over the course of the month, the NOAA coral watch for Maldives dropped from ‘Alert Level 1’ down two levels to ‘Watch’. We hope this marks the end of the high temperatures for Kuda Huraa, and that we may start to see signs of recovery in June.

Coral Monitoring

The team continued with the ongoing bleaching monitoring of 391 colonies on our Reefscapers frames, over 3 species, at 5 different sites around Kuda Huraa. Out of the 5 sites, the Water Villas and Channel are the most shallow, and were the first to bleach in April and have been very badly affected since. This month, we calculated mortality rates to be 93% (Water Villas) and 99% (Channel).

The coral bleaching montage images show Before (5 March), During (30 April), and After (27 May) for the three species we monitor. These colonies are located on frames by the Seastar at 1.5m deep. We will continue to monitor the bleaching, to see if any of the colonies are able to recover.

Ongoing Bleaching Monitoring

During extreme heat waves, not only corals are affected; anemones also experience the loss of endosymbionts (zooxanthellae). As we conduct the bleaching surveys every two weeks, we are also observing changes in sea anemones. Over the course of one month, one anemone at the Channel site went from healthy (15 April), to pale (28 April), to completely bleached (13 May).

Clownfish and anemones may be the most iconic symbiosis example at a macroscopic level, but a lot is going on at a microscopic level too. The clownfish will swim constantly between the tentacles of the anemone, allowing the movement of prey, nutrients, oxygen, and water flow; but their microbes are also strongly related, both metabolically coupled and functionally related.

So what is the effect of the bleached anemone on their clownfish? It can have consequences on clownfish behaviour and physiology, changing foraging patterns, and increasing the risk of predation (more visually conspicuous in a white host.) Bleached anemones can recover, and we will continue monitoring over the next few months.

Stormy Season

May brings the start of the wet season in the Maldives, and this year the El Niño event has amplified regional weather patterns, resulting big storms and rough seas across the whole country and wider Indian Ocean region. Following the storms, we observed that some of our coral frames had been flipped, and  several of our larger bespoke structures had been moved or suffered collapse. Fortunately, no major damage has been done, and we will be working to correct the damage during June, with the arrival of calmer weather.