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 (Nannochloropsis) – Overall, 400L of algae were produced throughout the month, useful for our newly hatched clownfish larvae.
– Rotifers – Following last month’s crash, population density this month has increased from 8 ind./mL to 396 ind./mL, mostly thanks to the new 100L algae bucket. As population increased, we have increased food quantity per session from 0.5mL to 2mL of our Nannochloropsis microalgae, given 3 times a day.
– Brine shrimp (Artemia) – culture mass has increased in two ways: (1) the usual batch has increased from 3g to 4g of cysts per day; (2) a new batch containing 5g of cysts is developing in one 6L balloon flask to feed our settlement coral polyps. On a daily routine, brine shrimp nauplii are extracted and homogenised with a blender, whereas unhatched cysts left are added back to the flask with 3g of fresh cysts.
Fish Lab Breeding Programmes
- Moon Jellyfish (Aurelia aurita) – populations remain healthy.
- Groupers (Epinephelus fuscoguttatus) – Overall, 22 small individuals (<116g) died this month, leaving 472 thriving fish in our grow-out tanks. From September to November, overall biomass increased from 71.2kg to 80.0kg; average individual mass increased from 142g to 168g, and average length from 18.2cm to 19.6cm. Re-grading was based on size, with all individuals distributed to equalise the population densities across our nine 1000L tanks. Average daily food has decreased significantly from 2.1kg to 1.7kg; average individual daily consumption has decreased from 4.3g/day to 3.6g/day, possibly caused by overpopulation stress and/or food quality. We have started to store the food (silver sprats, ‘rehi’) in vacuum bags to better preserve nutrients.
- Sea Grapes (Caulerpa racemosa) – This month, we delivered 225g of sea grapes to the Resort’s Kitchen, with approx 30g scheduled every 3 days. To increase production, we harvested a new batch of sea grapes from Kihadhoo on 17 November. To extend our growing area reliably, we have added another blue tub and installed water filters of synthetic sponge foam. We are also using one of the 1000L grouper tanks for a growth trial.
- Clam Grow-Out – After relocating our rescued baby clams to our indoor tanks they started to bleach due, perhaps due to high light intensity and fast-flowing water. So we then relocated them to our sea pond where they have now regained their colour and continue to grow.
- Clark’s anemonefish (Amphiprion clarkii) – The couple living in tanks 3 and 5 produced 3 and 2 batches of eggs this month respectively. On the 26th and 27th, eggs hatched two nights in a row with a total of 28 on the first night and 126 individuals on the second night. All hatchlings were transferred to tank 16 in which algae/rotifers are added daily (see larval growth photos, below). A dimmed light is activated since larvae were added to make sure individuals spot their food but also not to be blinded and disorientated. [Lifecycle graphic]
Guest Excursions
At Kuda Huraa this month, a total of 219 guests enjoyed 31 different excursions to 5 different underwater sites in the area, where we recorded 12 different megafauna species.
At Landaa Giraavaru, we conducted 7 guided tours of our Marine Discovery Centre for a total of 34 Guests. Over 11 Dolphin Cruises for 72 guests, we recorded sightings of 352 Spinners plus 35 Bottlenose, with one exciting appearance by a tiger shark!
Our guided snorkel excursions were enjoyed by 242 guests. The luckiest megafauna encounter to date this year was our fantastic Turtle Safari to Kudarikilu, where we sighted an ornate eagle ray (Aetomylaeus verspertilio) alongside a reef manta (Mobula alfredi) and four hawksbill turtles (Eretmochelys imbricata). We also conducted 6 private excursions, with one particularly lucky trip to nearby Hanifaru Bay finding not only manta rays but also a juvenile whale shark!
Team Updates
In November, we welcomed the arrival of our two new interns, Jessie and Tiana! They will be here for the next three months and we are so excited to have them as a part of our MDC Team!
- Tiana has just graduated from the University of Plymouth (UK) and is excited to put her underwater skills and public outreach toward the guest experience.
- Jessie travelled all the way from New York to Kuda Huraa. She received her Bachelor’s degree from Bates College in May of this year, and has significant experience in community engagement and research.
MNU School Visit
The Marine Discovery Centre hosted a very special school visit with students from Maldives National University to dive not only into conversations about marine conservation, but also into the water! Our second year star apprentices (Aman & Raaidh) were part of this class, and played a role in showing their peers one of our restoration sites. Everyone got into snorkel gear and went out to the Blue Hole to learn first-hand about how our in-water restoration work is conducted. We practised taking monitoring pictures with those who wanted to dive down and try! It was such a pleasure to host these incredible and passionate students who are the future of the field. We wish them all the best and hope to see them again soon!
Staff Snorkel
Sharing the underwater world with those who don’t get to be in the water is always a highlight! This month, we led a staff snorkel with the help of other departments, exploring one of our most beautiful snorkel sites – Coral Gardens. This is an incredibly special spot that is home to many different coral species who are the foundation for an abundance of fish and other animals. This excursion was lucky enough to see not only the beautiful expanse of reef, but also a feather tail stingray (Pastinachus sephen), blacktip reefshark (Carcharhinus melanopterus) and one very fast hawksbill sea turtle (Eretmochelys imbricata). We look forward to the next month’s staff snorkel!
Maldives Sea Turtle Rescue & Rehabilitation
Sea Turtles Released with Satellite Tracking Tags
Follow the journey of Harry our Olive Ridley sea turtle patient, recently released with a satellite tag to enable us to monitor their journey in the big blue. Visit our turtle page or our dedicated project page for more details – Turtle Satellite Tracking. Harry seems to have reached a favourite wide-area feeding ground, and is maybe building up strength.
Toby Updates
Last month, we admitted a juvenile hawksbill turtle nicknamed ‘Toby‘ into our Sea Turtle Rescue Centre. He had been rescued in a very weak and dehydrated condition from the neighbouring local island of Huraa.
REEFSCAPERS Coral Propagation & Reef Restoration in the Maldives
At Kuda Huraa during November, our coral experts monitored (cleaned, repaired, photographed) a total of 124 growing coral frames, and transplanted 3 new frames, kindly sponsored by guests (2), plus 1 recycled frame.
This month has been highly productive for our coral team. We completed maintenance across all four restoration sites, and dedicated much of our effort to House Reef. We witnessed and documented spawning in five different Acropora species and monitored 75% of Noah’s Rock. In addition, we carried out cull dives and maintenance at the water-villa reefs, refreshed the Blue Hole, and are preparing the channel restoration site ahead of the upcoming festive season. Overall, it’s been a strong month of progress across all our reef sites.
At Landaa this month, we monitored 159 existing frames, and transplanted 23 new coral frames, kindly sponsored by guests (10), the Resort (13), and online (0). In total, we added ~1000 new propagated coral fragments to the reef.
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.
World Kindness Day
Our Landaa team constructed a dedicated frame with guests and staff to mark ‘World Kindness Day’. This was done to celebrate the start of a long-term initiative aimed at progressively developing a staff reef ecosystem beneath the wedding pavilion. This project has been designed as a monthly collective effort, with the goal of contributing one meaningful addition at a time. Beyond creating a shared visual feature for staff and guests alike, the initiative promotes teamwork, creativity and a shared sense of ownership, while also reinforcing our ongoing commitment to marine awareness and stewardship.
An example of activities that will be carried out for the staff reef ecosystem: 1 day each month a educational talk (focused on that month’s newest addition) will be conducted in conjunction to a in water activity for those who are interested.
Coral Spawning – see our full report at Reefscapers
At Landaa, we witnessed multiple coral colonies spawning around the November full moon period, in a multi-species mass coral spawning event. Notably, for the first time in two years, spawning activity was sufficiently intense across two separate nights to generate a visible surface ‘slick’ (concentrated layer of eggs and sperm on the water’s surface). The formation of this slick is a strong indicator of successful synchronized spawning and overall reef reproductive health.
Further News & Updates
You might also be interested in our specialised Sea Turtle Lagoon Enclosure, and our Dolphin Diaries & ID Project.
Looking for details of our Reefscapers coral propagation and reef restoration program ? Then head over to our Four Seasons Team Diaries at Reefscapers.
You can sponsor your own frame and see photographs (updated every 6 months) in our Coral Frame Collection at Reefscapers.
Junior Marine Savers activities: (1) Reefscapers corals, (2) turtle care.
