Be sure to read our monthly updates from Marine Savers – direct from our resident teams at
the Marine Discovery Centres at Landaa & Kuda Huraa – our long-term partnership with Four Seasons Resorts Maldives.
Landaa Giraavaru
At Landaa during April, we transplanted 26 new coral frames, kindly sponsored by guests (5), the Resort (12), and online (9), adding ~1500 new coral fragments to the reef. These new frames were positioned mainly at “The Plankton” site near Charlie’s Head, where they are often seen by divers. We also monitored (cleaned, repaired, photographed) a total of 216 frames at all sites around Landaa Giraavaru.
To see the progress of your own frame, please visit our dedicated Four Seasons monitoring page where we upload new photos every 6 months or so.
Coral Spawning, Maldives (April Full Moon)
We performed monitoring night snorkels around the Full Moon period (13 April). We had previously observed the presence of gametes in several Acropora species, and successfully recorded spawning events in Acropora as well as various other species (Goniastrea, Galaxea, Montipora, Cyphastrea, Dipsastrea).
Tagged Colonies – Of the 88 colonies recorded spawning this month, 6 were previously tagged (Galaxea species). New spawning colonies received an ID tag starting with “LGM..”. A full set of ID photos was taken (wide, mid, close-up, corallite detail) and stored in the LGM ID database for genus/species identification. This month, 78 new colonies were added to the massives database.
Coral Settlement
To monitor coral embryogenesis (in Goniastrea retiformis), we conducted overnight observations to record the first cellular divisions. We observed development of the multi-cellular blastomeres, through the Morula, “Prawn chip” and Bowl stages, culminating in rounded embryos with slight movement (by late afternoon). Our practical steps were:
– Gametes transferred into containers of fresh seawater, gently mixed for 5–10 minutes (agitating the bundles, encouraging egg and sperm release).
– Left undisturbed for 5 minutes to allow buoyant eggs to float to the surface (sperm settled below in a cloudy layer).
– Floating eggs were skimmed and transferred to a new container of fresh seawater. A sperm wash was performed by repeating this transfer process, to reduce fouling. The eggs were then placed in ~600 mL fresh seawater.
– To each container of eggs, 100 mL of sperm water from the opposite colony was added. The contents were mixed (10 mins) to encourage fertilisation. Only a small volume of sperm water was used to limit the chances of polyspermy, which can increase the likelihood of developmental issues and mortality.
– Each jug was added to a separate open-flow tank system equipped with a specialised drainage setup; water exited through a fine mesh filter at the bottom, allowing the eggs to float undisturbed to the surface.
Kuda Huraa
At Kuda Huraa this month, our coral experts transplanted 15 new frames, kindly sponsored by guests (11), the Resort (3), and online (1). In addition, we monitored 66 growing coral frames (repopulating 50 of these).
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.
Coral Relocation – Noah’s Rock
In early April, we received a kind guest donation to fund the relocation of 788 coral colonies from Ras Male, which faces governmental coastal development. With a huge effort from the relocation team and the Reefscapers team at Kuda Huraa, all colonies were strategically positioned on our house reef according to species depth preferences. We have since attached all Acropora and Pocillopora colonies and fragments to frames, and placed all massives on Noah’s Rock.
This relocation introduces significant genetic diversity into the house reef, increasing its resilience to environmental stressors. Many of these colonies are of mature size, giving us hope they will form part of our network of spawning colonies. We extend our gratitude to Thomas and the whole team who collected and transported the corals from Ras Male to Kuda Huraa.
Over the following months, we will monitor the progress of these relocated colonies as they adapt to their new environment. Currently, all colonies have survived the relocation, with 10 Acropora colonies showing signs of paling but none showing signs of total bleaching. Once adapted, these colonies can become donors in our propagation project.
Corallivores
During April, we observed fewer predators than in recent months (13 Corallivorous Starfish + 437 Corallivorous Snails). This may be due to our extensive control efforts, or possibly environmental or seasonal factors affecting corallivorous species populations. Regardless, it remains important to continue routine predator culling to protect corals at restoration sites around Kuda Huraa.
Coral Bleaching in the Maldives, 2025
Throughout April, we started to notice paling of coral fragments and some colonies outplanted at shallow depths (<4m). Some colonies in the Blue Hole are partially bleached or fluorescing due to stress in response to increased sea surface temperatures. Compared to the 2024 bleaching event, current bleaching is significantly less severe. We will continue monitoring throughout May to assess whether severity increases. In response to shallow fragments paling, we are outplanting new frames deeper than usual to protect them from warmer surface waters.
Coral Spawning
Over the full moon period this month, our team conducted 25 hours of spawning monitoring, and successfully recorded spawning in 25 colonies (of 7 Acropora species). All but 1 species recorded spawning this year had also spawned during the April full moon period of 2024. Significantly fewer colonies spawned this year compared to last April; however, many colonies have semi-pigmented eggs, suggesting they might spawn during the May full moon.
