Fish Lab & Aquaria – Marine Life in the Maldives

Our new aquarium resident, a painted spiny lobster (Panulirus versicolor) is now out of brief quarantine and living in Tank 35, along with Maldivian cardinalfish and bicolour blennies.

Plankton Production – Our plankton and algae cultures are used as the main food source for the residents of our Fish Lab.

– Algae – stable production of 1000L this month, to feed the juvenile fish and shrimps in our breeding program, and to grow brine shrimp to adult size.
– Rotifers – population decreased to 857 individuals/mL, due to fewer hungry fish larvae this month.
– Artemia – culture has been increased from 7.5g to 8g of cysts a day, to feed our growing population of fish, shrimps, and moon jellyfish (Aurelia aurita). We have been using larger 5L bottles and 6L flasks to grow the Artemia for two days before harvesting them.
– Copepods – Of the two 15L Kreisel tanks settled last month, the tank with an elevated constant temperature produced a thriving community of larvae and adults. Around 300mL of Nannochloropsis live algae is added daily to each Kreisel tank, with weekly water changes to keep the environment clean.

Jellyfish – Aurelia aurita

Our large Kreisel display tank population currently stands at 397 individuals. At the end of May, we observed some individuals in poor health (bell erosion, bell inversion). We suspected a decline in water quality, which was confirmed by subsequent chemical testing that revealed elevated levels of ammonia, nitrites and nitrates.

Groupers

On 19 May, one grouper was spotted swimming upside-down, a common symptom of a swim-bladder disease. The swim bladder is an organ that regulates buoyancy in all bony fish, but it can be adversely affected by grow-out conditions (overfeeding, malnutrition, infection). We isolated the individual in a quarantine tank to avoid contamination or worsening of symptoms. After 9 days of close observation and occasional feeding, the grouper seems recovered. We have started to feed all the grow-out fish every two days to avoid overconsumption.

Sea Urchins – New Project 2024

Sea urchins are often collected for food around the world. Some countries have over-harvested from the wild, so we launched our new echinoculture project to investigate methods of breeding the collector urchin (Tripneustes gratilla), chosen for its small spines.

The sea urchin population is still thriving by getting fed regularly with carrots and various vegetables provided by the kitchen. As sexual dimorphism is non-existent in sea urchin, gender identification was performed by gently shaking the individual to release gametes. So far, 3 individuals have been identified as females, and 5 individuals are still to be determined.

Ornamental Fish & Shrimp Breeding

Boxer shrimp (Stenopus hispidus) – Two spawning events occurred this month, though none of these larvae were collected due to tank availability.

Clark’s anemonefish (Amphiprion clarkii) – population is growing steadily; the juveniles born 23 January continue to thrive, and the older batch (13 January) has now been moved into a display tank. [Lifecycle graphic]

Maldivian clownfish (Amphiprion nigripes) – The main tank breeding pair laid eggs on 21 May, fixed on a rock underneath the anemone.

Blue damselfish (Pomacentrus pavo) – A batch of 40 larvae was collected on 24 May, and moved to a grow-out tank with a small airflow (and without water flow). Copepods and algae were introduced as food, but unfortunately, the larvae died on Day-3.

Onespot damselfish(Chrysiptera unimaculata) – our first ever batch was collected on 31 May; unusually, the larvae started to hatch before ‘nightfall’ (Fish Lab lights off). Overall, 250 individuals were collected and placed inside a grow-out tank with a small airflow (and without water flow). Water changes will be performed several times per week; copepods and algae are added as food.

Fish Lab jellyfish breeding Maldives

Fish Lab: growing tiny jellyfish in our Kreisel tanks

Megafauna and Marine Life

During May, we welcomed a total of 148 guests to our Marine Discovery Centre at Landaa Giraavaru. On our snorkel excursions, hawksbill turtles (Eretmochelys imbricata) were the most commonly sighted species, followed by blacktip reef sharks (Carcharhinus melanopterus), spotted eagle rays (Aetobatus narinari), nurse sharks (Ginglymostoma cirratum) and pink whipray (Himantura rai), plus we had an exciting encounter with two giant trevally (Caranx ignobilis) hunting along the reef.

At Kuda Huraa, 70 guests joined us across 13 guided excursions. A highlight this month was the rare sighting of a whaleshark (Rhincodon typus) in Malé Atoll; this lone adult female was spotted at the Lankan Dive Site.

Climate Change and Marine Life
Anthropogenic climate change is the vector of global changes in our oceans, but its impacts are not limited to the loss of coral reefs. Increasingly, we are witnessing the exacerbation of weather events in intensity and frequency across all regions of the globe. In the Maldives, the elevated ocean temperatures combined with the seasonal monsoon rains that characterize El Niño events, to bring storms with heavy rainfall and strong winds. As a consequence, waters in North Malé Atoll have been filled with large amounts of plankton, attracting pelagic filter-feeders like whale sharks. Climate change related environmental impacts are of increasing interest (eg: coral bleaching, ocean acidification) but very little is actually known about possible alterations in the spatial ecology of large filter feeders as a consequence of changing plankton distribution.

Dolphin ID Marine Savers Maldives

Dolphin encounters are always a thrilling experience!

Whale Shark Maldives at Kuda Huraa

Rare whaleshark sighting in Malé Atoll

Maldives Sea Turtle Rescue & Rehabilitation

turtle heads - our inpatients

Turtle Rescue & Rehabilitation

On 16 May, we admitted a new turtle rescue patient, Kan’bulo, a large (32kg) adult female Olive Ridley that had been washed ashore entangled in a large ghost net. After 10 days, we needed to amputate her severely damaged flipper, but she is now recovering well and making every effort to dive.

Ozone Therapy for Turtles

Ozone (O3) was discovered over a hundred years ago and has since been widely used in many areas, primarily as a disinfectant. More recently, the use of ozone has been extended to treat pathologies, playing an important role in wound-healing and modulation of immune cells, amplifying therapeutic possibilities in pain and infectious diseases. Animal treatments remain in the development stage, but ozonated oils are showing great results.
• Sciorsci et al (2020) – Ozone therapy in veterinary medicine. Research in Veterinary Science.
• Pivotto et al (2020) – Clinical Uses and Molecular Aspects of Ozone Therapy. Online Journal of Biological Sciences.

HAMEEDHA injured turtle released

HAMEEDHA: returned to the ocean after 20 weeks of care and treatments at our Turtle Rehabilitation Centre at Landaa Giraavaru

Maldivian Sea Turtle Identification Program

During May, our ID project is currently on hold as we have been busy with record numbers of rescued turtle patients, and are currently at full capacity.

Spotted a turtle?  Share your photos

Submissions consist of close-up photographs of the turtle facial profile, enabling us to outline the unique pattern of scales (scutes) that act like a human fingerprint.

Turtle ID Maldives - unique facial scales

REEFSCAPERS Coral Propagation & Reef Restoration in the Maldives

Reefscapers coral bleaching survey E44 (Mar-May)

Coral bleaching survey: colony E44 from healthy to paling to bleached (from Mar-May)

At Landaa during May, we transplanted 20 new coral frames, kindly sponsored by guests (5), the Resort (14), and online (1), adding almost 900 coral fragments to the reef. We monitored (cleaned, repaired, photographed) a total of 315 established coral frames at various sites around Landaa and Voavah.

At Kuda Huraa this month, our coral experts transplanted 6 new coral frames, and monitored a further 80 mature frames at various sites around the island.

May brings the start of the wet season in the Maldives, and this year the El Niño event has amplified regional weather patterns. The resulting large storms and rough seas hit the whole country and the wider Indian Ocean region. Following the storms, we observed that some of our coral frames had been flipped over, and several of our larger bespoke structures had been moved or suffered collapse. Fortunately, no major damage was done, and we will be working to correct the damage during June, with the arrival of calmer weather.

Coral Bleaching Season in the Maldives

The ‘summer’ hot season in the Maldives runs from January to May; the extra hours of seasonal sunshine, combined with the current elevated global sea surface temperatures (SSTs) cause increased stresses on coral reefs, leading to paling of the coral colonies, or even permanent coral bleaching and death. Global climatologists are forecasting 2024 to be exceptionally hot, due to a combination of the cyclical El Niño event and the ever-increasing effects of anthropogenic climate change. Over on our Reefscapers Climate Change page, we are following developments very closely by curating the news reports from climate experts and marine scientists worldwide.

We have been closely tracking NOAA’s Coral Reef Watch bleaching guidelines. After two months at “Warning/Alert 1” status levels, we are now at “Watch” status thanks to the arrival of the seasonal monsoon. As such, we hope to see some recovery of bleached/pale corals as water temperatures decline.

  • March – moderate paling was observed in some colonies along Landaa’s House Reef.
  • April – bleaching and fluorescence at all sites across Landaa, at depths of 1m-15m.
  • May – more widespread bleaching around Landaa, plus some mortality was recorded across all sites. As expected, corals of the genus Acropora have been bleaching (and dying) more than other genera, with colonies in shallow water at the Water Villas and Elephant site being the most affected. Bleaching has also been noted in some Pocillopora and massive genera such as Porites.
Acropora millepora bleached (marine biologist Maldives)

A bleached coral colony of Acropora millepora, on our Reefscapers frame.
The coral polyps are still alive, and may recover if the elevated ocean temperatures return back to normal in time.

Coral Bleaching in Malé Atoll

May saw continued bleaching and mortality of corals around Kuda Huraa and the North Malé Atoll. We partnered with our Dive colleagues to assess the health of nearby natural reefs at popular dive sites, revealing bleaching levels of 32% to 40%.

On Kuda Huraa’s House Reef, bleaching has reached natural corals down to 22m depth, and affected our coral frames down to 15m. Due to the continuing elevated ocean temperatures, the shallow corals that bleached during April had sadly died and became overgrown by algae. We have calculated coral bleaching rates to be 90% or even higher across our coral frame sites.

During extreme heat waves, sea anemones are also seen to lose their endosymbionts (zooxanthellae).
BELOW: Losing colour (15 April), to very pale (28 April), to completely bleached white (13 May).

Junior Marine Savers activities

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.

Junior Marine Savers children turtle care Maldives