Reefscapers reef regeneration Maldives coral propagation

Monthly report updates from our Reefscapers coral biologists at Kuda Huraa and Landaa Giraavaru.

You may also be interested in:

  • Our previous Reefscapers Diaries from 2016 onwards (including our extensive 2016 coral bleaching report).
  • The ground-breaking lab work and unique photography (Oct-Nov 2021) in our Coral Spawning Reports.
  • Sponsoring your very own coral frame as part of our Reefscapers coral propagation and reef regeneration projects;
  • Viewing the latest photographs of your coral frame (uploaded every 6 months) – see our Coral Frame Collection.

Reefscapers Diary July 2022

Coral Propagation – Monthly Progress

At Landaa during July, we transplanted 36 new coral frames (24 guest-sponsored, 11 Resort-sponsored, one online order) adding a total of 2400 coral fragments onto the reef. We also monitored (cleaned, repaired, photographed) 108 coral frames at various sites around the island.

We are continuing to build our generous guest sponsorship of 50 large frames, adding a further 13 frames this month to give a total of 35 frames at Mudikaashi Reef (an area of degraded reef at the Dive Site). To ensure genetic diversity at this large new site, we have spent time harvesting coral fragments from all around Landaa Giraavaru. So far, we have repopulated this area with 3710 coral fragments, with a further 1590 fragments to go (15 remaining large frames.)

At Kuda Huraa this month, we transplanted 11 new coral frames (nine guest-sponsored, two Resort-sponsored). Additional coral work included monitoring and mapping at the House Reef, and extensive maintenance work in the Channel site by our apprentices.

Coral Bleaching Monitoring

Coral colonies across different temperatures and bleaching outcomes from earlier this year were photographed in our shallow coral propagation sites: the Water Villas, and the Turtle (rescue coral).

  • The Water Villas is a shallow site with well-settled coral and optimum health. Corals of different species, colours and sizes were monitored for a period of 91 days. 16% of 400 corals presented signs of severe paleness or bleaching, but we saw recovery rates of 100%. (The Drupella outbreak that occurred after the bleaching season destroyed several colonies due to their higher susceptibility.)
  • The shallow Turtle site is populated by newly imported rescue corals (with relocation stress) and so higher bleaching rates were observed (32% of 200 corals). We monitored this site for 73 days; although many corals did not recover, the colonies that did survive have now recovered well.
  • Resilience of coral morphs: Green > Purple > Brown.

Published studies (Satoh 2021) find that brown morphs are more susceptible to bleaching (and death) than purple morphs, whereas green morphs appear to be the most resistant to thermal stress (as they maintain photosynthetic activity).

Reefscapers monitoring coral bleaching Maldives
Rescue Coral Health Monitoring

Our control small-sized coral frames were monitored to estimate survival rates across the sites: 64% survival on average, but only 48% at the Channel site. Corals in the shallow areas of the House Reef and the Turtle site exhibited better health, possibly due to fewer corallivores (such as Crown of Thorns (COTs) and Drupella snails.)

Reefscapers coral rescue reef monitoring

Spawning Monitoring

At Kuda Huraa during 2021-2022, gametes have been observed in 12 different species, with actual spawning events witnessed and recorded in four species.

During July, we conducted five surveys (at night) to look for signs of coral spawning.

  • Starfish site – white eggs in two species (A. humilis, A. secale).
  • Water Villas – pigmented eggs in three species (A. digitifera, A. latistella, A. muricata); due to the later absence of gametes, we assumed that spawning occurred on 14 July in both A. digitifera and A. latistella.

Reefscapers Diary June 2022

Reefscapers coral biologist Alejandra at Marine Savers Maldives

Alejandra, our Reefscapers coral biologist, Kuda Huraa

Reefscapers coral reef regeneration Maldives

Relocating our artificial reefs, Landaa Giraavaru

Coral Propagation – Monthly Progress

At Landaa during June, we transplanted 33 new coral frames (17 guest-sponsored, 14 Resort-sponsored, two online orders) using almost 2000 coral fragments. We also monitored (cleaned, repaired, photographed) around 200 existing coral frames at various sites around the island.
We are continuing to build the generous guest sponsorship of 50 large frames. This month, we completed a further nine frames, giving a total of 22 frames out-planted to Mudikaashi Reef (Dive Site). To ensure genetic diversity at the site, we have spent time harvesting more than 2200 coral fragments from all around the island.

At Kuda Huraa this month, we transplanted eight new coral frames (five guest-sponsored, one Resort-sponsored, two online orders) using 500 coral fragments. In addition, we monitored the House Reef site (removing Drupella snails), retransplanted the complete Turtle site, replaced some predated Water Villas corals, and relocated 30 frames buried by the seasonally shifting sands.

Temperature Profiles and Coral Bleaching Monitoring

This year, the NOAA Bleaching Alert season started on 30 March with ‘Watch’/’Warning’, and remained active until the middle of May, when the status was lowered to ‘No Stress’. We analysed the data from our lagoon temperature loggers at Kuda Huraa, to reveal a similar date pattern to the NOAA alerts. But we found an important difference in the data, as the first major temperature peak occurred four days before the NOAA bleaching alert was issued. On 26 March, our data shows the Channel North site peaked at 34.7°C (and recorded an overall daily average of 33.7°C).

Reefscapers temperature loggers 2022

Sea surface temperatures recorded by our loggers in the lagoon at Kuda Huraa (March to May 2022)

Coral Bleaching Monitoring

By the end of the bleaching season, our Kuda Huraa results are as follows:

  • Water Villas (shallow site with optimum coral health) – a total of 400 local colonies were monitored; 15% of corals were presenting signs of paleness or bleaching, but with good recovery rates and zero mortality.
  • Turtle site (shallow site with Gulhifalhu rescue corals) – we monitored 200 newly introduced colonies of different species and sizes. Around 31% of corals were pale/bleached; although double the rate, this is a good result considering the inherent stresses of the large-scale relocation project (we are yet to finalise the rates of recovery and mortality).
Reefscapers rescue corals stressed recovery

Rescue corals recovering from stress (April to June)

Rescue Coral Health Monitoring

At Kuda Huraa, many of the Gulhifalhu rescue colonies are already encrusting to the substrate, and the mass coral import has visibly increased marine biodiversity in the area. We focused our efforts on maintaining the Turtle and House Reef sites, reattaching any fallen or broken corals.

  • Boulder corals – we continue to use quadrats to monitor health and survival rates. Results show full recovery in 18 colonies that initially presented fish predation (only one colony presented new partial-death this month).
  • Small-sized frame controls – data analysis revealed survival rates varying from 54% (at the Channel site) up to 75% survival.

Coral Predation

During June, a total of 90 Drupella snails were removed from both new and local coral colonies in the House Reef and the Water Villas, shortly after displaying signs of thermal stress during April/May.

  • Saponari, et al (2021). Assessing population collapse of Drupella spp. (Mollusca: Gastropoda) Two years after a coral bleaching event in the Republic of Maldives. Hydrobiologia. 848. 1-14. 10.1007/s10750-021-04546-5.
    Found Drupella in aggregations of up to 62 individuals, two years after a bleaching event.
  • Bruckner, et al (2017). Predation by feeding aggregations of Drupella spp. inhibits the recovery of reefs damaged by a mass bleaching event. Coral Reefs. 36. 10.1007/s00338-017-1609-2.
    Found Drupella in aggregations of 250+ individuals following the 2016 bleaching event.

Spawning Monitoring

During June at Kuda Huraa, coral eggs were observed in two coral species on frames in the Water Villas and the Blue Hole.

  • Acropora latistella – pigmented (orange) eggs found: 8 March, 26 May.
  • Acropora digitifera – pigmented (pink) eggs found: 23 May, 26 May, 6 June.
  • Acropora digitifera – spawning: 7 May (around new moon); 2 June; 12 June.

We recently analysed our spawning data (2021-2022):

  • Gametes observed in 17 different coral species.
  • Spawning events recorded in four species (A. secale, A. plantaginea, A. tenuis, Montipora digitata).
  • Temperature/tide profiles were charted alongside spawning events, to aid the prediction of future spawning events.
Reefscapers coral spawning 24 Nov 2021

Coral Settlement Update

Our Acropora millepora and Acropora digitifera polyps from March/April 2022 are growing nicely. Regular maintenance includes removing any competition (algae) and keeping the tanks clean.

Tracking Gametogenesis

During June, we observed immature oocytes in A. squarrosa and A. plantaginea. As we near the second coral spawning season here in the Maldives (October/November), it is important we track gametogenesis. Understanding the reproductive biology at a local and regional scale is crucial to uncover how populations maintain fecundity.
Research shows that thermal stress reduces reproductive output of coral species, which in turn could hinder their ability to recover after disturbance. It is crucial we understand the reproductive biology of Acropora species in the Maldives, to better understand life history traits.

Maldives Marine Research Symposium (MMRS)

Our proposals have been accepted by the MMRS, for presentation at their symposium in August. We have been creating infographics and slides to detail our research findings on gametogenesis, embryogenesis, and coral spawning of both wild and frame colonies. This will also include a statistical review of our dataset to identify any similarities or differences between locations on spawning synchronicity.

  • Oral presentation: “Methodology for the use of coral larvae settlement ex-situ, for upscaling restoration of the declining Acropora species”.
  • Poster presentation: “Observational insight into coral spawning patterns on two Maldivian Reef Ecosystems”.

Six Month A.I. Analysis

To assess growth rates and mortality since last year’s annual review, we reanalysed our coral frame photographs using our bespoke AI software. The volume (in litres) of Acropora and Pocillopora coral species have both increased as follows:

  • Acropora volume was 4000L (2021 Q4), now increased to 6000L (2022 Q2)
  • Pocillopora volume was at 10,000L (2021 Q4) and is now over 15,000L (2022 Q2)
  • Volumes of dead corals appear to have remained steady
Reefscapers increase in coral volume 2017-2022

Increase in volume of Pocillopora corals on our articifical reefs, 2016-2022

Reefscapers Diary May 2022

Reefscapers reef regeneration Maldives
Reefscapers coral frames at Kuda Huraa water villas

Coral Propagation – Monthly Progress

At Landaa during May, we transplanted 14 new coral frames using a total of 542 coral fragments. In addition, we have been busy monitoring (cleaning, repairing, photographing) a total of 846 coral frames across all sites around the island. This month, we also relocated the last of our 300 Moon frames to the Elephant site; we arranged them neatly and mapped their QGIS coordinates.

At Kuda Huraa this month, we transplanted 15 new coral frames using a total of 1153 coral fragments. We spent time repairing some Gulhifalhu rescue colonies that were damaged in a storm brought in by the south-west monsoon (some coral colonies detached from frames and sustained damage). Also this month, we removed 100 Drupella snails from several corals colonies at the House reef, and monitored for predation by fish and Crown of Thorns starfish (COTs).

References
Boström-Einarsson, L. & Rivera-Posada, J. (2016). Controlling COTs using household vinegar. Coral Reefs 35, 223–228
• Dumas, P., Gereva, S., Moutardier, G., Ham, J., Kaku, R. (2015). Lime juice for COTs outbreaks in Vanuatu. SPC Fisheries Newsletter. 146, 47–52.
• Great Barrier Reef Marine Park Authority (2017). COTs control guidelines. GBRMPA, Townsville.
Moutardier G, Gereva S, Mills SC, Adjeroud M, Beldade R, Ham J. (2015). Lime Juice and Vinegar to Control COTs. PLoS ONE 10(9): e0137605.
NOAA Satellite and Information Service. Coral Reef Watch, updated 26 May 22.

Reefscapers coral health recovery 2022

Pale coral colonies regaining their healthy colour (photosynthetic zooxanthellae) as the ocean cools (April to May 2022) [click]

Reefscapers coral predation

Drupella snails removed from Acropora digitifera, and predation by COTs (bottom left) [click]

Coral Bleaching Monitoring

We conducted our coral watch assessment during the first week of May. Mature coral colonies are well settled, exhibit good health, and have survived the seasonal temperature peaks. We will continue to monitor the stressed colonies at shallow sites (Water Villas, Turtle) to assess their health and recovery in the coming weeks.

Reefscapers coral paling recovery

The stressed corals (in April) are regaining colour (in May) as the warmest season (Feb-April) turns into the SW monsoon

Reefscapers coral health 2021-22

As coral colonies mature, they become more resilient to stress from warmer waters (same colonies, 2021-2022)

Rescue Coral Health Monitoring

We continue to monitor our Gulhifalhu rescue corals:

  • 10% Healthy: no dead or decaying areas since introduction.
  • 18% Pale: discolouration due to temperature stress (can transition to bleaching).
  • 41% Bleached or fluorescing: due to the loss of symbionts; >20% alive.
  • 6% Predated: predation caused decay or death (<80%); caused by Drupella, fish, algae or sand smothering.
  • 25% Dead: >80% of total surface.

Kuda Huraa Temperature Profiles

The temperature profiles in our coral propagation sites follow similar patterns to the official NOAA bleaching alerts.

  • 22 March to 10 May – average temperatures above 31°C were regularly recorded.
  • 26 March – highest recorded temperature of 34.7°C.
  • 7 April – highest recorded temperature of 35.5°C.
  • 26-27 April – peak coral bleaching period (from field observations across all sites).
Reefscapers sea surface temperatures 2022

Sea surface temperatures (2022) recorded by our temperature loggers at Kuda Huraa (‘Channel North’ site)

Spawning Monitoring

Since October 2021 at Kuda Huraa, we have recorded gametes in 11 coral species, and witnessed spawning events in four different species (A. secale, A. plantaginea, A. tenuis, Montipora digitata).

During May, eggs were observed in three species on coral frames at the Water Villas. Interestingly, frames of A. digitifera that were relocated from the Water Villas to the Starfish site in January did not show signs of spawning. We also did not find any eggs in the Gulhifalhu rescue colonies.

Measuring April Spawned Colonies

This month, we measured the 52 colonies that spawned in April.  Increasing our knowledge on corals and their reproductive biology is important for assessing connectivity of regional coral populations. We hope to determine when corals mature by measuring the spawning colonies (ecological volume using callipers to measure height-length-width).

Coral Settlement Update

In our lab, the settled coral polyps continue to grow well, especially the Acropora plantaginea fertilised and settled in November 2021.

Reefscapers coral polyp growth A.plantaginea

Coral polyp growth – Acropora plantaginea

Reefscapers coral frames at Kuda Huraa water villas

Coral polyp growth – Acropora millepora

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

  • KH01 (Galaxea fascicularis; Acropora species) – removed for cleaning.
  • KH02 (Galaxea fascicularis) – good health.
  • KH03 (Acropora species) – removed for cleaning.
  • 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.
Reefscapers artificial coral reef relocation Maldives

Reefscapers Diary April 2022

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.

Reefscapers Diary March 2022

Reefscapers coral reef restoration Maldives

Harvesting corals and collecting ‘fragments of opportunity’ for transplanting onto our coral frames

Coral Propagation – Monthly Progress

At Landaa during March, we used almost 2000 coral fragments to transplant a total of 31 new coral frames (18 guest-sponsored, 11 Resort-sponsored, plus two online orders). In addition, we monitored (cleaned, repaired, photographed) more than 400 coral frames at various sites around Landaa Giraavaru.
We also received a most generous donation that will enable us to make 54 new medium/large frames over the coming months, that will add an impressive 5600 coral fragments onto the reef.

Reefscapers artificial reef relocation Moon site

Reef relocation – Moon site (Landaa)

Reefscapers coral frame relocation artificial reefs

Relocating our coral frames (Landaa)

NOAA Coral Bleaching Watch Maldives

As we enter the seasonally warmer part of the year here in the Maldives (January to April), it is important to keep track of NOAA’s coral bleaching watch guidelines, as the sea surface temperatures are expected to rise slowly through to the end of May.

Over the next few weeks, the NOAA Coral Bleaching Alert for the Maldives will move from ‘Watch’ (and ‘Warning’) to ‘Alert Level 1’, as the sea surface temperatures threaten to rise above 30°C during May. We will start our CoralWatch monitoring during the last week of April.

Coral bleaching alert status Maldives

At Kuda Huraa during March, we transplanted nine new coral frames, and recycled two existing frames, using a total of 411 coral fragments from nine different species (mainly Acropora, plus Montipora foliosa).

During the last week of March, we helped with the major rescue of thousands of coral colonies from the large industrial development project at Gulhi Falhu (by the Maldives government). The colonies were divided up as follows:

  • transplanted to our existing frames on the House Reef,
  • wedged into suitable locations directly onto the natural reef,
  • stockpiled on the reef for future transplantation.
  • Water Villas (WV) – After the mass frame relocation in January, the 148 remaining frames are recovering and generally healthy overall. We performed some repairs, and the site is now fully mapped, tagged and monitored.
  • Sea Star (SS) – The 249 frames recently relocated here exhibit good health, but fish predation continues to be a minor threat. Monitoring, retransplanting, and remapping activities were continued, and all the frames are now fully mapped and monitored. Some frames were retransplanted with ‘fragments of opportunity’ (broken pieces that fall from recently relocated frames).
  • House Reef (HR) – the new Gulhi Falhu coral colonies will provide a massive boost in genetic diversity to our reef ecosystem around the island. Within minutes of replenishing an old frame with fresh corals, dozens of fish would arrive… a miraculous sight to behold!
  • Channel (CH) – further retransplanting and monitoring; Montipora digitata and Porites cylindrica seem less healthy at this site, perhaps due to the seasonally slow water current (causing increased temperatures and some breakouts of algae). The colonies that survived the last yearly bleaching event will continue to be monitored during the following months.
  • Blue Hole (BH) – coral health continues to be exceptionally good. Three additional flat frames were placed here this month and transplanted with some of the new Gulhi Falhu coral colonies. We will monitor these closely for health and possible spawning events.
Reefscapers coral rescue reef repair

Coral rescue and reef repair (Kuda Huraa)

Coral bleaching monthly sea temperatures

Sea temperatures recorded at our ‘Starfish’ site (Kuda Huraa)

Coral Spawning Monitoring

At Kuda Huraa this month, coral eggs were recorded in 28 frames (initially transplanted between January 2018 and December 2019) located at the Water villas (0.5m depth) and Starfish (1.5m depth) sites. Egg presence was recorded in six Acropora species (no eggs in Acropora humilis):

  • Acropora millepora: many colonies with white eggs.
  • Acropora digitifera: many colonies with eggs, which started pigmenting during late March.
  • Acropora nasuta: all colonies found with eggs, that started pigmenting during late March.
  • Acropora tenuis: a few colonies with immature pale eggs.
  • Acropora gemmifera: a few colonies with immature pale eggs.
  • Acropora monticulosa: one colony with pigmented eggs.

Coral Spawning Diary

  • 8 March onwards – egg maturity was observed in some colonies.
  • 18 March – full moon.
  • 16-22 March – we carried out night surveys. Monitored colonies were revisited to follow egg development, and on each visit we took photos and recorded: date, time, species, tag number. None of our monitored colonies spawned.
  • 18-22 March (around 20:00-22:00h MV time) – we observed ‘coral slick’ (pinkish eggs) floating on the ocean surface at two locations around the island (the sunrise and northern parts) probably from Montipora digitata.
  • For more indepth reporting and photos, please see our dedicated report on Spawning Research 2022.

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

• KH01 (Galaxea fascicularis; Acropora species) – new fragments were added to replace several mortalities.
• KH02 (G. fascicularis) – fragments continue to thrive. The largest fragments were removed to make a mini frame that was located at the Water Villas.
• KH03 (Acropora species) – many fragments were lost this month, so the plate will be retransplanted.
• KH04 (Acropora species, mushroom coral) – fragments continue to be healthy. The small mushroom corals have been removed by the resident crabs.
• KH05 (G.fascicularis) – fragments present steady health. The plate continues to accumulate cyanobacteria, which is regularly removed.
• KH06 (G.fascicularis) – fragments continue to be healthy and keep on fusing and growing.

Reefscapers coral frame monitoring Water Villas

Coral frame monitoring (Water Villas site, Kuda Huraa)

Reefscapers Diary February 2022

Reefscapers reef regeneration Maldives coral propagation

Reef restoration extends the natural habitat for a wide variety of marine species

Coral Propagation – Monthly Progress

At Kuda Huraa during February, we transplanted eight new coral frames plus one recycled frame, using a total of 448 coral fragments (from eight different coral species).

  • Water Villas (WV) – After the mass frame relocation carried out during January, the 148 remaining frames are either healthy or recovering well from the sand damage. During February, we monitored (repaired, photographed) 39 frames at this site.
    Immature white eggs were spotted in some coral colonies (Acropora hyacinthus, A. digitifera), and we are monitoring for a possible spawning event in the coming weeks.
  • Sea Star (SS) – The 249 frames recently relocated next to the Starfish are in good health, but fish predation continues to be a threat. Monitoring, re-transplanting and remapping activities will be resumed.
  • House Reef (HR) – This month’s nine new coral frames were deployed at this site; we also removed several Crown of Thorns starfish (COTs).
  • Channel (CH) & Blue Hole (BH) – some repair work and monitoring.

At Landaa during February, we transplanted a total of 2250 harvested coral fragments on 41 new coral frames (including a very generous guest donation for 16 frames).

Reefscapers artificial reef sand damage

Frame relocated to firmer substrate due to sand damage (lower bar)

Reefscapers coral propagation and monitoring House Reef

Newly positioned frame provides shelter for reef fish (House Reef)

Reefscapers heart-shaped frame Maldives

Heart-shaped frames for Valentine’s Day

Reefscapers coral health inspection

Coral frame monitoring and health inspection

NOAA Coral Bleaching Watch Maldives

As we enter the seasonally warmer part of the year here in the Maldives (January to April), it is important to keep track of NOAA’s coral bleaching watch guidelines, as the sea surface temperatures are expected to rise slowly through to the end of May.

During the upcoming weeks, we will move from ‘No Stress’ to ‘Watch’, followed by a Coral Bleaching ‘Warning’ status. We continue to monitor our coral frames and the natural reefs around the islands for signs of coral paling and bleaching.

NOAA coral bleaching watch Maldives

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

• KH01 (Galaxea fascicularis; Acropora species) – some paling and mortality, due to water flow issues.
• KH02 (G. fascicularis) – the fragments continue to thrive. The plate was rotated twice this month.
• KH03 (Acropora species) – some paling and mortality, due to water flow issues.
• KH04 (Acropora species, mushroom coral) – the fragments continue to be healthy, although the small mushroom corals have been moved again by the resident crabs.
• KH05 (G.fascicularis) – fragments continue to be healthy. We regularly clean accumulating cyanobacteria (and small sponges).
• KH06 (G.fascicularis) – fragments continue to be healthy.

Reefscapers Diary January 2022

Reefscapers reef regeneration Maldives coral propagation

Our artificial reefs provide habitats for myriads of fish and invertebrates, increasing marine biodiversity

Coral Propagation – Monthly Progress

At Landaa during January, we transplanted 20 new coral frames (11 Resort-sponsored, nine guest-sponsored) and monitored (cleaned, repaired, photographed) 266 existing frames. We used 1164 individual coral fragments for our new frames, plus 2130 fragments for repairs and recycling work, totalling 3294 fragments for the month.

  • Yin Yang site – we relocated all 31 frames to the Moon site, repairing and retransplanting as we went along.
  • Moon site – retagged, repaired and recycled 37 old frames.
  • Bissie’s Reef on the Coral Trail – repaired and recycled all 15 coral frames (at 10-12m depth).

At Kuda Huraa during January, we transplanted two new frames and three recycled frames, using a total of 270 coral fragments harvested from seven different Acropora species.
We also relocated 249 coral frames from the Water Villas site to the House Reef and monitored/mapped them at the new location.

  • Water Villas (WV) – from 8 to 10 January, we organised a mass frame relocation operation due to the increasing problem of the seasonally shifting sands. Due to the maturity, health, and weight of the coral frames, we required five to seven people for each session.
    Thanks to all our Resort colleagues who volunteered from every department.
    The frames were raised with buoyant canisters, transported in the whaler (four to 12 frames per trip) and relocated close to the Sea Star site. We worked for a total of 17 hours to relocate 249 fully grown coral frames of different shapes and sizes.
    Currently, 148 healthy frames remain at the Water Villas site, and are regularly monitored for health and encroaching sand.
  • Sea Star (SS) – the newly relocated frames were arranged, mapped, and monitored, and are in very good health overall, thanks to our rapid and efficient relocation work.
    The broken fragments were carefully collected, used to retransplant the starfish shape.
  • House Reef (HR) – the five new frames were deployed here, although we have started to observe some mortality due to the seasonally shifting sands.
  • Channel (CH) – the frame layout was simplified at the end of 2021, streamlining our mapping and monitoring work, and enhancing the snorkelling experience for Resort guests.
  • Blue Hole (BH) – frames remain healthy, and we continue to remove any accumulated marine debris that settles at this deep site.
Reefscapers reef rescue from shifting sands
Reefscapers artificial reef relocation & rescue
Reefscapers artificial reef relocation & rescue
Reefscapers reef rescue from shifting sands

Coral Spawning Database

Our new coral spawning database was created and shared among the team, to document our observations of gametes throughout the year. We will use standardised methods to collect observational information, including consistent categorisation of egg colouration (white, pale, pigmented).
We have also started work on a research paper and plan to submit for publication later in the year (after the March/April spawning event).

During January at Landaa, we observed white eggs in three species of both wild and frame colonies (A. nasuta, A. digitifera, A. millepora) and one frame colony with pigmented A. valida eggs.

  • 22 January – white eggs in Acropora digitifera on a Water Villas frame at Kuda Huraa.
  • 27 January – white eggs in Acropora nasuta (frame KH2444) and A. digitifera (KH2555), Kuda Huraa.

Coral Bleaching Watch

As we enter the seasonally warmer part of the year here in the Maldives (January to April), it is important to keep track of NOAA’s coral bleaching watch guidelines.

We are currently at ‘No Stress’ status, moving to ‘Coral Bleach Watch’ in the upcoming weeks.

We will regularly review the NOAA forecasts, and monitor our coral frames and the natural reefs for any signs of coral paling and possible bleaching.

Coral bleaching Maldives NOAA 2022

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

• KH01 (Galaxea fascicularis; Acropora species) – since September, the fragments continue to grow. New fragments were added due to removal by resident crabs.
• KH02 (G. fascicularis) – most fragments are healthy and growing. The plate was rotated twice this month.
• KH03 (Acropora species, replenished Oct-Dec 2021) – fragments continue to grow apically, and are encrusting well.
• KH04 (Acropora species, mushroom coral; replenished Oct-Nov 2021) – overall healthy, with increased growth.
• KH05 (G.fascicularis) – steady health; cyanobacterial growth is regularly removed.
• KH06 (G.fascicularis) – healthy, fusing and growing.