Fish Lab, Aquaria, and Marine Life in the Maldives
Plankton Production
Our plankton and algae cultures are used as the main food source for the residents of our Fish Lab.
– Microalgae – we have lowered the solutions for each volume due to reduced requirements, and produced 700L of algae by month end. For one 100L bucket of algae, 10% of the daily brine shrimp culture is added once per week.
– Rotifers – Since 6 March, only one bucket of culture is maintained. Following the fusion of both cultures, 2.5mL of Nannochloropsis microalgae is given three times a day (reduced from 3mL). The average rotifer concentration has increased to 662 ind/mL (way above our target average of 300 ind/mL.)
– Artemia – we have reduced the culture mass slightly, down to 7g of cysts per day, due to a decrease in the moon jellyfish population.
Groupers (Epinephelus fuscoguttatus)
- 2023 batch – 20 individuals remain from this batch, all sizes now merged from two tanks into a single 1000L tank. Individuals are eating less (from 267g to 229g each), likely due to increased grouper density causing elevated stress. This could lead to a slower growth rate that would affect the efficiency of the project (Williams et al., 2009). We will continue to monitor consumption and growth accordingly. Overall, average fish weight has increased from 884g to 925g, and average size has increased from 32.2cm to 32.8cm.
- 2024 batch – Two individuals died, but the remainder are thriving in two tanks, separated by size. Out of the 107 fish measured on 5 March, average weight had increased from 78g to 94g, and average size increased from 15.7cm to 16.7cm. Both tanks were fed twice daily, with the average daily consumption increasing from 202g to 246g (large tank), and a small increase in the small tank. Average weight gained per individual decreased from 23g in January to 16g in February. We plan to purchase new, larger tanks in the coming weeks.
- 2025 Batch – On 13 March, a new batch of 204 juvenile groupers arrived at our facility. The overall batch was divided into two 1000L tanks, each containing 98 and 106 individuals. Only one individual died (two days after arrival). The improved survival rates compared with previous batches could be explained by the regular siphoning of tanks once per day, to avoid the spread of harmful bacteria that could grow on uneaten food, and to reduce ammonia and nitrite levels by removing faeces.
Ornamental Fish & Shrimp Breeding
- Clark’s anemonefish (Amphiprion clarkii) – the pair living in tanks 3 and 5 produced 3 and 2 batches of eggs this month, respectively. Two of the batches of larvae were collected, with a further two due to hatch at the beginning of the month. [Lifecycle graphic]
- Boxer shrimp (Stenopus hispidus) – our one surviving male is thriving in his tank.
- Dancing shrimp (Thor amboinensis) – all individuals from the September and October batches are still thriving and growing.
- Pipe fish – one pipefish was noticed to be pregnant, although no larvae were successfully collected.
Guest Excursions
At Landaa Giraavaru this month, we conducted 9 tours of our Marine Discovery Centre for a total of 121 curious Resort guests, and three children enrolled in our Junior Marine Biologist Programme to study of seven different modules. Our 8 Dolphin Cruises were enjoyed by 51 guests in total, with recorded sightings of 360 Spinners plus 7 Bottlenose. We also conducted 12 private trips both above and below the waves. 130 guests joined our guided snorkel excursions (Adventure, Turtle Safaris, Night, Parrot Reef) and we recorded seven species of megafauna, including Hawksbill turtles, blacktip reef sharks, plus a fever of spotted eagle rays.
At Kuda Huraa, we conducted 42 excursions for 265 guests, visiting 6 different sites, and recorded sightings of 11 different megafauna species. Our most popular activities included guided snorkels at Coral Garden, Turtle Point, and Manta sites. Guests showed great enthusiasm during our educational briefings, especially those focusing on reef restoration and the identification of local megafauna. We also hosted 3 private excursions, tailored to guest interests in cetaceans, coral reefs, and sea turtle behaviour. Feedback was overwhelmingly positive, with several guests expressing interest in supporting Reefscapers’ initiatives through donations and coral frame sponsorship.
We have updated our activity pamphlets with a fresh design to align with Four Seasons branding, and we plan to start distributing business cards to sponsors of our coral frames, featuring their code and Reefscapers contact information. To enhance the guest experience, we have created three new posters featuring fascinating facts about sea turtles, corals, and Reefscapers research (telemetry studies on sea turtles, coral spawning, and cetacean identification).
Maldives Sea Turtle Rescue & Rehabilitation
15 Years of Sea Turtle Rescues !
Four Seasons Resort Maldives, Press Room: Our turtle conservation journey began in March 2010 with Oceane, rescued from a ghost net. Since then, 517 sea turtles have received care, 358 individuals were admitted to rehab at our turtle rescue centres, and 285 were successfully rehabilitated and released. Satellite tags have helped study migration patterns of Green, Hawksbill, and Olive Ridley turtles. Since 2012, 35 turtles have been tagged.
Some unreleasable turtles have been transferred to aquariums worldwide via our pioneering Flying Turtles Programme, becoming ambassadors for marine conservation. See also: our look back after 10 years of turtle rescue.
Ultrasonographic Imaging to Treat Sea Turtles
Ultrasonography is a valuable, non-invasive, and cost-effective diagnostic tool, particularly for examining coelomic organs in chelonians. It aids in diagnosing various conditions and is vital for post-mortem evaluations. For sea turtles, standardising techniques is essential to establish normal gastrointestinal indices. Regular use in rehabilitation centres simplifies diagnosis and monitoring of rescued sea turtles.
During March, our veterinary team used ultrasonography to evaluate the internal condition of Maw, who has been showing decreased appetite and lethargy. While no major abnormalities were found, the scan will help track any changes and guide future treatments.
One major challenge is that sea turtle anatomy presents six small ‘acoustic windows’ that enable the visualisation of organs and structures:
A) Fourth and fifth cervical vertebrae, the spinal cord, and the venous sinuses of the external jugular vein.
B) Heart, hepatic lobes, and distal end of the oesophagus.
C) Right: partial heart view, stomach, and right liver lobe.
D) Left: stomach and left hepatic lobe.
E) Urinary bladder and portions of the reproductive tract.
F) Posterior coelom – intestines and kidneys.
The image shows the 6 acoustic windows that are available for ultrasound scanning of sea turtles, due to their unique anatomy.
The image was copied (and then enhanced) from the paper on Ultrasonographic imaging by Valente et al (2007).
New Patient – Vazeeru
An olive ridley sea turtle was found floating on the ocean surface, and transferred to us by the resident marine biologist at a neighbouring resort. Her injuries were indicative of entanglement in ghost gear (discarded fishing nets that drift long distances into Maldivian waters).
Vazeeru is currently active in her tank, and under close supervision. Check her page for the latest health updates.
Maldivian Sea Turtle Identification Program
Our ID project is currently on hold as we have been busy with record numbers of rescued turtle patients.
REEFSCAPERS Coral Propagation & Reef Restoration in the Maldives
At Kuda Huraa during March, our coral experts monitored (cleaned, repaired, photographed) a total of 96 growing coral frames, and transplanted 9 new frames, kindly sponsored by guests (3), the Resort (5), and online (1).
At Landaa during this month, we monitored 127 existing frames, and transplanted 30 new coral frames, kindly sponsored by guests (13), the Resort (15), and online (2). In total, we added ~1600 new coral fragments to our reefs at the Whale Tail and Charlie’s Head sites.
To see the progress of your own frame, please visit our dedicated Reefscapers Four Seasons monitoring page where we upload new photos every 6 months or so.
Be sure to read our complete Team Four Seasons Diaries over on our Reefscapers website, and then browse our Global Research pages where we curate the latest marine science research (open access) alongside news on how the oceans are being changed by climate change.
New milestone: 9,000 Planted Coral Frames! #levelunlocked
Four Seasons Resorts Maldives, Press Room: In collaboration with Reefscapers, Four Seasons Resorts has successfully planted its 9,000th coral frame—marking a major milestone in a marine conservation journey that spans more than 20 years. The initiative began after the 1997–1998 El Niño bleaching event. Coastal oceanographer Thomas Le Berre introduced coral propagation to Four Seasons Maldives, which resulted in one of the largest artificial reef systems in the Indian Ocean—covering 3.05 acres (2,351 m²). Thomas’s research led to the development of a coral frame technique now used globally. Coral fragments are attached to metal frames, which are then placed on the seabed to encourage reef regeneration.
Why do we use plastic cable ties to attach the coral fragments to our coral frames ?
This is a very common question that is regularly asked of our coral experts! The simple answer is that we haven’t found a better alternative … so far! But we are currently working closely with Chestnut Biopolymers in the UK on a bespoke manufacturing solution for 100% biodegradable cable ties. Read more over on our Reefscapers site.
Further News & Updates
You might also be interested in:
– our ongoing Dolphin ID Project, our specialised Sea Turtle Lagoon Enclosure, and our Zooplankton Monitoring Project.
Looking for details of our Reefscapers coral propagation and reef restoration program ? Then head over to our Reefscapers Diaries for all the latest updates.
You can sponsor your own frame and see photographs (updated every 6 months) in our Coral Frame Collection.
Junior Marine Savers activities: (1) Reefscapers corals, (2) turtle care.
