Reefscapers Diary March 2022

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.

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.

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.