Reefscapers artificial coral reef relocation Maldives
Reefscapers artificial coral reef relocation Maldives

Coral Propagation – Monthly Progress

At Landaa during April, we added a total of 3300 coral fragments to the reef, transplanted onto 47 new coral frames (sponsored by guests [36], the Resort [8], online [3]). We also monitored 434 coral frames around Landaa Giraavaru, cleaning and repairing them where necessary, and sending out updated photographs to our valued sponsors.

Raft Building and Frame Relocation

During April, we initially relocated 40 frames from our ‘Moon’ site to the ‘Elephant’ site, and then built a custom raft to help transport a further 176 of the larger and heavier coral frames.

NOAA Coral Bleaching Watch Maldives

During the hottest time of year in the Maldives (January to April), we pay close attention to NOAA’s coral bleaching alerts – the sea surface temperatures (SSTs) can gradually rise to the end of May (as seen last year, 2021). This year, NOAA warned of possible elevated SSTs of 31°C by the end of April.

Over the upcoming weeks, the NOAA Coral Bleaching Alert for the whole of the Maldives is expected to lower from ‘Warning’ to ‘No Stress’ levels, as the oceans start to cool again with the arrival of the seasonal monsoon winds and rain.

  • 10-20 May 2021 – ‘Warning’ status with SSTs exceeding 30°C. Acropora hyacinthus was the most heat resilient species, and A. tenuis the lowest. Overall, 60% of monitored corals presented at least slight paling (score 2), with 40% remaining healthy throughout the study (score 3+). Healthy corals were recorded across our sites as follows: Sea Star (50%), Water villas (45%), Channel (29%).
  • 23 April 2022 – Monitoring started for 6 weeks; our ocean temperature loggers are recording every hour. From our field observations, the paling/bleaching became more severe around 26-27 April.
NOAA coral bleaching alerts Maldives 2022
NOAA coral bleaching alerts Maldives 2022

CoralWatch – coral health colour scale

Reefscapers coral bleaching natural house reef

Coral bleaching, natural house reef (Kuda Huraa, April 2022)

Reefscapers coral health monitoring Acropora 2021-22 Maldives

Acropora coral health monitoring (2021-22)

Reefscapers coral health monitoring Acropora 2021-22 Maldives

Acropora coral health monitoring (2021-22)

During April at Kuda Huraa, we transplanted nine new coral frames, recycled four frames (for Junior Marine Savers activities), and transplanted 23 old frames (RK0101 to RK0123) with large coral colonies rescued from Gulhifalhu. This month’s transplanting and recycling work required over 2000 coral fragments.

Most of our time spent on coral propagation and reef regeneration work was to relocate the rescued Gulhifalhu coral colonies in a mass coral relocation effort. An impressive 10,000 coral colonies were brought to us in 12 boat loads over one week, filling 40 ‘hanging baskets’, and taking 11 people a total of 525 man-hours in the water (free-diving and scuba). We retransplanted 400 very old frames located at all sites around the island, and added some colonies directly to the natural reef.

The Gulhifalhu corals were mainly species of Acropora, followed by Porites and Pocillopora, all of which will significantly increase the genetic diversity around Kuda Huraa. We are continuing to work hard on this project, and we are excited to see how the corals will settle into their new homes. A set number of frames per site have been tagged, mapped, and uploaded, and will be regularly monitored for health and mortality.

  • Water Villas (WV) – The 148 remaining frames continue to be safe from sand movement, but we have observed signs of fluorescing, paling, and bleaching of various species (peaking on 26-27 April). Colonies of Pocillopora and small Acropora were worst affected by the seasonally high temperatures at this relatively warm and shallow site.
  • Turtle (TU) – newly rescued staghorn corals from Gulhifalhu were observed to be paling (26 April), so we are experimenting with shading techniques before the arrival of the monsoon rains. Ten recycled frames (RK110-119) were selected for regular monitoring; they have been GPS-mapped and photographed as baseline markers.
  • House Reef (HR) – the rescued Gulhifalhu corals were transplanted at depths of 4-16m (on frames, and on the natural reef). The natural reef here is very healthy, but some of our new coral colonies have started to pale and fluoresce due to the inherent stresses of relocation.
  • Channel (CH) – local colonies (especially Porites cylindrica) are well-adapted and heat resistant, having survived the elevated seasonal temperatures from recent years. Some newly transplanted Gulhifalhu colonies are showing signs of bleaching, due to relocation stress and the seasonally high ocean temperatures.
  • Sea Star (SS) – The 249 frames recently relocated next to the Sea Star are in good health overall, but some coral colonies started to pale at the end of April. Mature coral eggs were found in Acropora millepora (photos below), but we did not observe the spawning event.
Coral eggs Acropora millepora

Acropora millepora eggs (oocytes) – pale/white

Coral eggs Acropora millepora

Acropora millepora eggs – mature pigmented

Coral Plates in Aquarium One (plates KH01, KH02, KH05) and Aquarium Two (plates KH03, KH04, KH06)

  • KH01 (Galaxea fascicularis; Acropora species) – more new Acropora fragments were added.
  • KH02 (Galaxea fascicularis) – the fragments continue to thrive. The plate was rotated two times this month.
  • KH03 (Acropora species) – more new Acropora fragments were added.
  • KH04 (Acropora species, mushroom coral) – the fragments continue to be healthy.
  • KH05 (Galaxea fascicularis) – the fragments continue to be healthy.
  • KH06 (Galaxea fascicularis) – the fragments are healthy, fusing and growing.