Marine Biology projects at Sheraton Maldives

1.     Coral Propagation Project

1.1. Old frames

In February 2020, 50 frames were transplanted at the Sheraton Resort, all sponsored by Sheraton Maldives Full Moon Resort & Spa. These coral frames were transplanted on the north side of the island with 10 flat placed along the bridge that goes from the resort to the spa, 30 small, medium or large placed in a small depression on the west side of the spa in front of the water villas and 10 flat along the water villas. At low tide, the flat frames are about 1m deep and the other frames are between 2m and 3.5m.

Due to covid-19, these frames were not maintained or monitored until November 2020. In November, dead corals were removed from the frames – approximately 30%. Algae were also removed from the frames and coral fragments collected from either the spa or the boat channel were re-transplanted on the frames.

These corals probably died due to the water temperature that is very high in this area with an average temperature of 30 degrees at the bottom. It can go up to 32 degrees at the surface. Depending on the season, algae grow relatively fast in this area which is also one potential reason why a lot of corals died. These frames are now maintained weekly by removing algae and ensuring that frames and corals are not being buried in the sand.

1.2. Coral Frame sales

In November, 2020 5 frames (4 small frames and 1 heart frame) were adopted by guests from the Sheraton Resort and transplanted in the lagoon. All the new frames were placed on the west side of the lagoon next to a substrate with a few colonies of Acropora and Pocillopora that were placed there in June 2020. They are about 1.5m deep depending on the tide.

1.3. Monitoring

Water villas

The 50 frames transplanted in February were monitored after new fragments were transplanted.  The corals that survived are well attached to the frames and have started to grow new branches.

Lagoon

All of the new frames were monitored and uploaded on the website. So far, corals seem to attach well to the frames. Fragments that were transplanted at the beginning of November are slowly beginning to encrust over the cable ties. 

1.4. Maintenance

Water villas

The 50 frames by the water villas and the spa are maintained weekly. At the moment, the visibility is poor with warm temperature and algae grow relatively fast in this area. The lower part of some frames also get buried in sand quickly. Dead corals were placed underneath the frame to ensure they don’t get buried.

Lagoon

The new frames are maintained regularly as algae grow relatively quickly in the lagoon and thus on the frames. The sand movement is also high in this area and stays on top of the coral fragments that could lead to bleaching if not maintained well.

2.     Coral colonies relocated from Gulhi Falhu

In May and June 2020, Reefscapers was appointed by the Maldivian Government’s Environmental Protection Agency (EPA) to relocate coral colonies of Gulhi Falhu to the Sheraton Maldives Full Moon Resort & Spa. These frames were placed in a pyramid shape in front of the dive centre and in the lagoon. There are 8 pyramids in front of the diving centre and 4 in the lagoon.

2.1. Coral colonies – dive center

Overall state of coral colonies

Overall, coral colonies are healthy and are adapting to the new environment. It is presumed that about 5% of the colonies died either soon after transplantation due to stress or difficulty to adapt after transplantation. As these frames were not monitored since June 2020, the date at which they bleached then died is not known.

Dead coral colonies were removed and hidden underneath the frames to ensure it is the least visible by guests when they dive or snorkel in this area. Some of the coral colonies that died were Acropora cytherea, Acropora digitifera and Pocillopora. Some coral colonies probably died because of the relocation and difficulty to adapt to the new environment.

Healthy coral colonies are attaching well to the frame and are started to grow. Tables corals are also growing horizontally on the frames as the pedestal is tipped over.

Maintenance

Some coral colonies were “hanging” on the frames as the cable tie either broke since it was attached or it loosen up with time. These coral colonies have been re-attach tightly to the frames and will hopefully soon start to attach. This happens relatively often and it requires maintenance to ensure the coral colonies do not fall from the frames.

After dead colonies were removed, coral fragments were re-transplanted on the empty space of the frames at the beginning of November and throughout November. These fragments are already attaching well to the frames.

A few sponges are growing on the frames which could potentially be an issue with time but they are being removed and maintained regularly. Ascidians such as Didemnum molle are also growing on the corals and being removed when needed. One or two colonies were covered by the coral-eating sponge Haliclona nematifera.

Coral colonies from Gulhi Falhu relocated on coral frames at Sheraton Maldives

Table corals that started to grow horizontally

2.2. Coral colonies – lagoon

Overall state of coral colonies

Overall, coral colonies in the lagoon are also doing well. It is presumed that 2% of the coral died. Corals colonies are attaching well to the frames and some colonies are also starting to grow. The visibility is very poor in this area and it is difficult for guests to snorkel above those frames.

Maintenance

Coral colonies that died have also been placed underneath the frames. Sponges or Ascidians are less present in this area and one or two colonies have also been covered by the coral-eating sponge Haliclona nematifera. Dead colonies were removed and placed underneath the frames.

There is still a lot of maintenance to do in the lagoon such as re-transplanting coral fragments on empty spot on the bars, removing a few other dead colonies and ensuring that there is space between coral colonies to avoid competition. Due to the sand movement, some coral colonies on the bottom bars of the frames are sometimes being buried in the sand which can lead to bleaching. This has to be maintained well to see if this is becoming an important issue. 

2.3. Future maintenance

Coral have to be maintained regularly by:

  • Transplanting coral fragments if there is enough empty space / dead colonies
  • Finish to attach all the colonies that are not tight enough on the frame
  • Removing algae when it is becoming an issue
  • Removing sponges or ascidians if necessary
  • Ensure that sand is not being deposited on corals on the lower frames. To avoid this, branching corals will be placed on the lower bars if necessary.
  • Avoiding coral competition. Coral competition is appearing with a few species fighting for space. To ensure that there is enough space for corals, some fragments of colonies will be fragmented and moved on empty spot on the frames.

Acropora attaching to natural substrate

Acropora attaching to natural substrate

2.4. Acropora and Pocillopora in the lagoon

Acropora and Pocillopora species were placed on the north-west side of the depression on a hard substrate in May/June. These corals were placed in between rocks or holes to ensure they will attach to the substrate and not be taken away by the current. Overall, they attached well and most of the Acropora species are already well attached to the rock. Fragments that were not well attached have been re-placed on a hard to substrate to attach and will be monitored. Some coral colonies died due to either stress, water temperature or sedimentation. New coral frames have been placed next to these coral colonies.

This is a shallow area where guests can easily walk so educating guests on the importance not to touch or stand on corals will be important.

2.5. Massive coral colonies – water villas

Massive coral colonies were placed along the water villas in June 2020.  They were placed in between rocks or corals to avoid them to roll over as much as possible and some underneath the bridge at the spa. Overall, they are adapting to the new environment and most of them survived. However, with the current, some of them rolled over and bleached. More maintenance is needed to ensure they don’t roll especially when there will be strong current in this area.

2.6. Monitoring

A coral monitoring system is going to be implemented in December to follow the health and growth of the corals. Frames will be monitored and photographed from on each side and from above.

Healthy coral colony growing onto and over the metal frame

Shifting sands in the lagoon can cause mortality in lower positioned corals

3.     Marine Biology

The marine biologist of the Sheraton is now participating in marine activities with Watersports. This includes snorkelling safari, reef snorkelling, dolphin cruise and occasionally diving. In November and especially beginning of November, data during snorkelling trip were not recorded so data below are not well representative of the actual megafauna of snorkelling excursions. Data will be recorded daily in December.

3.1. Megafauna Sightings – Snorkelling excursions

During the month of November, a total of 23 sharks, 3 turtles, 70 rays and 12 fish were sighted during snorkelling or diving excursions.

3.2. Dolphin Cruise

Spinner dolphins (Stenella longirostris) is the most common species sighted in the surroundings of Sheraton Resort and they were seen on each dolphin cruise this month. Recording of the number of individual, number of guests attending and the most common behaviour was not done this month and a recording system will be put in place with Watersports for December 2020.

3.3. Marine activities in the resort  

Marine Presentation

Marine presentation will be done 3 times a week with presentations about coral reefs, dolphins and sharks and rays. A turtle activity is also in the process of creation.

Kids club

2 activities a week will be put in place with kids club to create marine activities for kids. One activity will be to “Build a reef” and the other one will be an activity on turtles. They are slowly being implemented in the resort.

4.     Objectives for December 2020

4.1. Coral Propagation Project

  • Keep maintaining coral frames in the water villas and lagoon on a weekly basis.
  • Upload the Reefscapers brochure on Sheraton QR code
  • Identify marine life present in the frames around the Water Villas and the Spa.
  • Display Reefscapers brochure on the wall of the marine biology office
  • Presentation of the project through a video to display on marine biology office TV

4.2. Coral Fortress

  • Create a monitoring system to do every 3 months.
  • Finish the main maintenance of the corals and keep maintaining them on a regular basis.
  • Identify marine life present in each area

4.3. Marine Biology

  • Record the number of dolphin sighted and the different behaviours during dolphin cruise
  • Record megafauna sighted during snorkelling excursions
  • Create a spreadsheet for Watersports to record dolphin and megafauna sighted during excursions when the marine biologist is not present.
  • Identify and describe all of snorkelling and dive sites
  • Participate in 1 snorkelling activity a day
  • Participate in 2 dolphin cruises a week
  • 3 presentations a week at the resort Anchorage bar in front of the lagoon at 17:30 – Coral reef, dolphins and sharks and rays
  • Training sessions for the front office team to explain coral frames adoption

4.4. Some objectives for 2021

  • Create a 1 or 2min video on the coral fortress relocated in May 2020 – this will also be done with the help of the intern.
  • Marine life and coral frames training sessions for Sheraton resort staff
  • Put in place a snorkelling activity with guests around the resort to talk about the coral propagation program and the adoption of coral frames.
  • Create a Resort Map with the Coral Garden Locations to display
  • Monthly or trimestral green committee with one person from each department to try and reduce waste around the resort
  • Create a marine board game for kids club
  • Virtual tour of coral frames