Four Seasons Team Diaries: November 2024

At Landaa this month, we (again!) transplanted 19 new coral frames, kindly sponsored by guests (7), the Resort (10), and online (2), adding ~1000 new coral fragments to the reef. We monitored (cleaned, repaired, photographed) a total of 359 established coral frames at various sites around Landaa and Voavah. We actively remove any corallivorous species encountered during our maintenance work, which this month included 245 Drupella snails, 5 Monodonta snails, and 6 cushion stars.

Seabar Frames: we relocated 35 medium-sized frames from the Seabar/ Elephant site that had suffered 100% mortality following this year’s coral bleaching event. We moved these frames to the entrance of the seawall, where high water flow and plentiful recruitment of wild corals suggests this site will be good for our newly transplanted fragments. So far, 12 old frames have been fully recycled, with completion of this project being a priority for next month before the sponsors’ return to Landaa in January.

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 Settlement

🗓️ November 2023 – gametes from 2 colonies of Acropora secale were collected and successfully settled ex situ. Following a year of growth in our Fish Lab, 10 coral recruits were fitted into concrete moulds (“coral cookies”) to hold the coral settlement plugs for cementing on the reef.
🗓️ 30 October 2024 – 5 of these recruits were out- planted onto the reef by cementing onto stable substrate on the House Reef. Recruits were planted at depths ranging from 2m-5m. Monitoring pictures were taken so that growth in situ can be monitored over time. A steel “cage” was placed over one of the recruits to reduce predation from larger fish.
🗓️ This month – we recorded predation in 4 of 5 recruits, with the only surviving recruit being was under the cage. So we now plan to plant the remaining settlement plugs under this cage. We observed paling in the surviving recruit two weeks post-out-planting, but it is now recovering.

🗓️ Coral Spawning around the full moon of 15 November

Early this month, we noted varying stages of gamete development in several Acropora species. Nightly snorkels were scheduled around the 15 November full moon, looking for bundling of mature coral gametes. On nights where multiple genera needed to be observed, one freediver collected data on the House Reef, while two SCUBA divers collected data at our Dive Site.
During this period, we initially observed spawning in various colonies of Montipora and Goniastrea, later followed by colonies of Acropora and Galaxea. We also deduced spawning via loss of gametes in species of Acropora.

At Kuda Huraa this month, our coral experts transplanted 9 new coral frames. During monitoring, we actively seek and remove known corallivores that eat the living corals (this month: 7 crown-of-thorns starfish, 5 cushion starfish, 589 corallivorous snails). This month, we also conducted 27 hours of underwater monitoring over 13 days, looking for signs of coral spawning.

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 Maintenance

In a massive team effort, we used a local dhoni (traditional Maldivian boat) to load and transport a total of 150 coral frames from the Channel site, which was devastated by this year’s mass global coral bleaching event. These frames will now be recycled and used for other projects.
Over the course of the month, we continued to clear and repopulate coral frames in the Water Villas and House Reef. During October, we pruned large quantities of excess branching Acropora from the healthy pyramid bars, and used these fragments to help repopulate the Water Villas frames. Initially, many fragments started to pale and bleach in their new environment (not unexpected) so we are closely monitoring their acclimatisation. We have also harvested Monitpora foliosa from the Blue Hole site, and used these fragments to help repopulate the Water Villa frames.

Coral Spawning

After October’s coral spawning event, many Acropora colonies clearly had pigmented eggs remaining, so we scheduled our spawning monitoring around the 15th November full moon period. We successfully observed spawning over several days in various species of Acropora on the House Reef. In addition, our gamete checks revealed white eggs in various Acropora colonies, indicating a possible upcoming spawning event in December (later than previous years).

Resilient Corals: Genotype Experiment

This month we began creating frames with tracked genotypes. The aim is to repopulate frames with resilient corals following this year’s coral bleaching event. We will be repopulating these frames with at least two genotypes of a species, tracking both donor frames and new frame locations. On the House Reef, we will be moving these corals to the bottom of the reef crest to preserve them from high temperatures.

In addition to preserving resilient corals, we are also testing wild Acropora colonies from our Blue Hole site that survived the bleaching in depths as shallow as just 0.5m. We have tagged these natural colonies of Acropora vermiculata to create replica frames at the Water Villas, Channel and in the shallows of the House Reef. We selected Acropora vermiculata, as we have many large colonies that recovered well after the bleaching event.