Coral Spawning Observations

The best way for reefs to recover from any disturbance is to repopulate through natural sexual reproduction, thereby increasing genetic diversity and abundance of corals on the reef. Coral spawning occurs when male and female gametes are released, fertilized and then settle on the reef to become a new coral colony. However, in the Maldives, little is known about the exact timing of this event, which is often species specific. In 2019, the Six Senses marine biology team had started surveying Six Senses Laamu house reef for spawning activity around the full moon in March and two species (Diploastrea heliopora and Porities lobata) were observed releasing male gametes 3 nights after the full moon. On the same day in 2020, a third species (Goniastrea retiformis) was observed releasing gamete bundles on this same day. Despite these observations, with 36 different coral genera have been recorded on Six Senses house reef, and 47 in Laamu, there is still much more research needed to understand this critical event. Now with a clearer idea of when spawning occurs, the Six Senses marine biology team are conducting a more detailed and targeted research project into coral spawning and recruitment success.

LIFE AFTER

BLEACHING

We are witnessing the coral reefs in the Maldives change, and not for the better. Historically, live coral covered an average of 42% of reefs in the Maldives. But, in 1998 a catastrophic event occurred. Prolonged unusually warm sea surface temperatures caused the reefs of the Maldives to fall victim to its first mass coral bleaching event. This resulted in live coral coverage to decrease by an average of 93%. Just when the reefs seemed to have recovered disaster struck again and in 2016 three weeks of unusually warm waters caused 73% of Maldivian corals to bleach. Here at Six Senses Laamu, marine biologists witnessed this first hand and documented the decline on reefs near the resort.

National Coral Reef Monitoring Program

Since 2018, Six Senses Laamu’s House Reef has been established as a permanent reef monitoring site under the Climate Change Adaptation Program (CCAP) launched by the Maldivian Ministry of Fisheries, Marine Resources and Agriculture. The program was launched following the catastrophic mass coral bleaching event in 2016, where a rise in sea surface temperature resulted in an average loss of 75% of Maldives’ shallow corals. Three years worth of data from the Six Senses Laamu’s site has been reviewed to give an indication of the reefs’ recovery up to December 2020. The results showed that total live coral cover increased from just 12% in March 2018 to an impressive 25.9% in June 2020. However, due to temperatures exceeding 30 degrees celsius, 16% of coral that year were recorded as bleached, and this likely resulted in the drop in live coral cover to 18.4% recorded in December 2020. The data proves the reefs are recovering from the 2016 mass bleaching event, but the rate of recovery is hindered by continued smaller scale bleaching events.