[D]uring April, we transplanted 22 new coral frames into the lagoon at Kuda Huraa, and monitored/photographed a total of 150 existing frames all around the island (at the House Reef, Water Villas, Spa and Channel). Over at Landaa Giraavaru we have made a further 45 frames this month, and monitored a total of 188 more (around the Moon/Reef and Yin Yang areas).
We are now recording the GPS locations of our coral frames using Google Earth to plot the co-ordinates, which is simpler than our old method.
Coral Bleaching
Water temperature was seen to peak at 31C from mid-April, but thankfully the arrival of cooler weather towards the end of the month should mean the incidents of coral bleaching will be low this year.
Drupella Predation
We have been seeing an increase in the populations of Drupella snails recently, living on our coral frames, with the older frames in particular showing some signs of damage. More than 300 snails were removed this month, mainly from the many affected Acropora coral species affected (A. robusta, A. humilis, A. digitifera, A. nasuta, A. tenuis).
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- Coral Bleaching of Acropora hyacinthus
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- Drupella damage on a coral frame
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- Drupella damage on corals
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- Closeup of Drupella damage
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- Drupella predating on Acropora tenuis
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- Drupella snails removed from coral frames
Molluscs that are known to eat corals
Our new Apprentices were given some training this month, on how to identify the various species of coral-eating molluscs they may encounter on our frames.
[1] Ornamented Coral Shell (Coralliophila costularis), family Muricidae
- Bluish in colour with a lavender aperture; 24-60mm in length
- Feeds on soft & hard corals
[2] Rugose Drupella (Drupella rugosa), family Muricidae
- Shell is conical-shaped, a creamy white to orange colour; 20-35mm in length
- Grazes on tissue of live corals, and forms feeding aggregations
[3] Hairy triton (Cymatium pileare), family Ranellidae
- Distinctive hairy appearance; pairs of inner aperture teeth; 30-90mm in length
- Feeds on coral and small molluscs
[4] Castor Oil Drupe (Drupa ricinus), family Muricidae
- Distinctive spiky shell, with variations of yellow, black and white; 19-32mm in length
- Feeds on molluscs and barnacles
[5] Robin-redbreast Triton (Cymatium rubeculum, Septa rubecula) , family Ranellidae
- Reddish colour with white and yellow markings; 25-55mm in length
- Feeds on clam and oysters
Shell Collection – Molluscs that are known to eat corals
