Reefscapers Diary December 2020

Coral Propagation – Monthly Progress

At Landaa, we transplanted 21 new coral frames (10 sponsored by guests; 8 by the Resort; 3 online) and created a new festive frame (“Sunshine” at the Dive Site).

At Kuda Huraa, we transplanted 12 new frames and recycled 5 old frames. We continued monitoring our existing frames at the Water Villas, and at the Channel Site we finished GPS-mapping the existing frames and continued our refurbishment efforts (necessary due to build-up of sand and sediment). On 25 December, our festive Christmas Tree frame was retransplanted with Pocillopora fragments, with the help of 5 guests and the dive team.

Reefscapers coral frames in the lagoon around Landaa Giraavaru

Temperature loggers

We retrieved temperature loggers from around the island, and plotted the Sea Surface Temperature (SST) data from the past 7 months. Average high temperature peaks were recorded as 31-32°C, with maxima of:

• 32.0°C peaks at the Channel Site;
• 30.1°C at the House Reef (deeper site with reduced temperature fluctuations);
• 32.3°C at the Water Villas, although overall average temperatures are lower due to the ocean currents.

Ocean temperature readings at 3 different sites around Kuda Huraa (May to December 2020)

Coral Reproduction Spawning Experiment

All our growing coral specimens have been moved to a new aquarium to combat the continued issues with algae.

Artificial Intelligence and Coral Identification

Read the full project history of our autonomous catamaran and AI coral identification project over at Reefscapers AI-4Corals.

Good examples of recently transplanted coral fragments, healthily encrusting over their cable ties

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

All 5 coral plates in both aquaria are regularly cleaned to remove algae. There were a few mortalities, and the crabs continue to push the fragments out, but the plates remain healthy overall.

• KH01 – (recently replenished) – fragments of Acropora millepora just beginning to fuse. The fragments of Galaxea fascicularis that were added last month remain healthy and are starting to encrust.
• KH02 – (exclusively Galaxea fascicularis) – showing a little mortality, so we have rotated the plate several times to allow all fragments to receive more light.
• KH03 – thoroughly cleaned of algae. The calcified areas are growing and about to fuse. The fragments of Acropora valida remain healthy and continue to grow, although they haven’t yet calcified onto the plate.
• KH04 (replenished December) – also cleaned of algae. Only two original fragments remain (due to the loss from algal overgrowth) and of the 11 newly transplanted fragments, 4 have started to calcify onto the plate (photos, below).
• KH05 (exclusively Galaxea fascicularis) – 1 fragment died after bleaching, but the others have now regained a healthy colouration and continue to grow (2 fragments are encrusting).

KH05 Galaxea fascicularis