Aquarium jellyfish Marine Savers Maldives
Jellyfish (Aurelia aurita) in our growing tanks at the Fish Lab (Landaa Giraavaru)

Fish Lab & Aquaria -Marine Life in the Maldives

Fish Lab

Down in our Fish Lab, we are continuing to revise our protocols and methodologies. Algae production is strong, and now requires changing every 4-5 days; Rotifers have stabilised and the numbers are growing. The strobilation of the new jelly fish has begun, with a higher-than-expected yield from a single tile.

Plankton Production

Our revised algae production implemented last month has proven successful, and we can now maintain 4 x 100L and 4 x 20L buckets over the month. This has made it incredibly easy to maintain our Rotifer safety net.

With the arrival of our new Rotifer feed, we have been experimenting and settled on a feed ratio of 0.63ml/million Rotifers (as recommended for a daily 20% harvest rate). The numbers have risen steadily and consistently, and there has been little build-up of waste, therefore avoiding the cycle of quick growth/increased ciliates/population crash. This also allows us to feed the Rotifers accurately and measurably in a way that can be easily replicated (new to our Fish Lab), with yeast quantities estimated day by day.

The Artemia have been more challenging. We now create a safety net of frozen Artemia every 2-3 days to ensure enough food should there be any issue with aeration overnight. This method also allows us to track our usage (448g cysts/tin gives 224 ‘portions’). We will begin counting on a bidaily basis to calculate average number of Artemia produced, and start comparing total number of Artemia as opposed to Artemia/ml.
After a few incidents of both explainable and unexplainable drops in hatching success, we have revised our methods to improve success rates, to more easily identify any issues:

Old method:

  • Batch partial-hydration of cysts + remove unhatched
  • Estimate and hydrate a suitable amount of partially hydrated cysts daily for up to 24hrs, to provide enough food for the following day
  • Separate hatched from unhatched and provide the feed as required

Revised method (simple, more measurable, fewer unhatched cysts):

  • Hydrate 2g cysts in 2L salt water daily (additional 2g to provide a tray of frozen feed as required)
  • 24hrs later, separate the hatched from the unhatched
  • Feed as required

Zooplankton Study

While we await the equipment delivery, we have created a simple database to use for data collection. We have also been collating a library of scientific papers on plankton (Indian Ocean, climate change, etc).

We held a video call with zooplankton expert, Anthony Richardson, (CSIRO Australia), discussing formalin concentrations (with safe handling/disposal), and the actual identification of the zooplankton (majority will be copepods). We plan to purchase:

  • Flow meter (vital for getting volume measurements and adding validity to our data)
  • Small oven (to determine biomass of samples, widening our scope of applications at a low upfront cost)
  • Scientific weighing scales (to weigh dried samples)

This is a great opportunity to be the first long-standing plankton study in the Maldives, with potential for future growth and interaction both locally and globally.

Small Aquarium One

  • Mini coral frame – 4 dead fragments removed; 16 new fragments added (Acropora species).
  • Maldivian clownfish (Amphiprion nigripes) breeding pair – no eggs this month.

Small Aquarium Two

  • Mini coral frame – 5 dead fragments removed; 9 new fragments added (Acropora tenuis).
  • Clark’s anemonefish (Amphiprion clarkia) – 3 batches of eggs.

Linckia multifora sea stars

  • SS3 (large specimen) – growth in all arms.
  • SS4 (new Jan 21) – growing steadily (especially shorter arms).
Marine aquarium Maldives

Our large 4000L marine display aquarium at Landaa Giraavaru

Marine aquarium Maldives [DSC_1613 (2)] Multipore sea star Linckia multifora

Multipore sea star (Linckia multifora)

Junior Marine Savers study module

Junior Marine Savers – we are expanding our practical course for children and teenagers, and developing new educational modules.

Fish Lab Aurelia aurata jellyfish euphyra strobilation

Aurelia aurata jellyfish euphyra – strobilation

Aurelia morphology diagram

Aurelia aurata jellyfish euphyra, close-up

Jellyfish – Aurelia aurita

  • During a routine tank clean at the start of April, the remaining jellyfish rapidly fouled the holding tanks, reducing their numbers.
  • After a few incidents with the UV light, we were forced to stop the pump and drain off the heated water, resulting in bubbles entering the tank when the pump was switched back on, damaging multiple bells.
  • From the single tile at 13°C, the strobilation [*] began on 19 April; after 8 days, we stopped at 3399 euphyra (when size differences between new and older individuals became apparent). This required bidaily water changes and an accurate Artemia feed.
  • We will plan to keep a small group of jellyfish in pure salt water. After finding recommendation of 32-33 ppm salinity (our consistent sea water), we may be able to stop using the mix of 10% freshwater and 90% salt water (28-29ppm salinity) and use an open flow system to increase turnover and reduce waste. This will also reduce any stress caused by the final transfer into the main jellyfish cylinder. The main cylinder should be available for the new jellyfish by the time they reach the appropriate size.
  • [*] Strobilation is defined as asexual reproduction by transverse division of the body segments which develop into separate individuals.

REEFSCAPERS Coral Propagation & Reef Regeneration in the Maldives

Monthly Progress

At Landaa during April, we monitored a total of 343 coral frames around the island, and transplanted 24 new frames (9 sponsored by guests, 15 by the Resort).

At Kuda Huraa, we transplanted 4 new coral frames, recycled 5 of our older frames, and monitored a total of 185 existing frames.

Bleaching Alerts – The NOAA coral bleaching alerts system categorises Maldives in “Watch” status for April-May, rising to “Warning” for June. Currently, we have not observed any coral bleaching on the natural reef or our coral frames.

Microfragmenting Trial – We are continuing our  coral  propagation techniques, initially explored in 2019-2020 on ‘massive’ coral species.

Check out our Reefscapers Diary for further details and all our latest photographs, including updates on our autonomous catamaran and coral identification project that uses bespoke artifical intelligence.

Coral bleaching Maldives alerts NOAA

Sea Turtle Rescue & Conservation

Luna-3 stranded Olive Ridley turtle Maldives ghost nets

Luna, an Olive Ridley turtle, found floating on the ocean surface (unable to dive) and sent to our Turtle Rescue Centre on 25 April 2021.

Sea Turtle Rehabilitation

At the close of April, we were caring for 8 Olive Ridley turtles (Lepidochelys olivacea) in our Rehabilitation Centre at Landaa. At Kuda Huraa, our turtle patients include 2 rescued Olive Ridleys (Maracuja was successfully released), plus our rehabilitating hatchlings: 5 Green turtles (Chelonia mydas) and 8 Hawksbills (Eretmochelys imbricata).

Flying Turtles

With the global pandemic restrictions slowly lifting, we have restarted discussions with several of our long-term overseas partners, who are interested in housing our non-releasable turtle patients as part of our Flying Turtle initiative.

Maldivian Sea Turtle Identification Program

During April, we received 9 submissions from the public to our Sea Turtle ID project. Our current database catalogues 5,000 photographic sightings, and to date has positively identified and named a total of: 1300 Hawksbills, 271 Greens and 98 Olive Ridleys.

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.

Spotted a turtle?  Share your photos

Turtle ID Maldives photo submissions Hawksbill male
Junior Marine Savers activities

Further News & Updates

You might also be interested in our Dolphin ID Project, and our unique Sea Turtle Enclosure out in the lagoon at Landaa.

Looking for details of our Reefscapers coral propagation and reef restoration program ?

Head over to our Reefscapers Diaries for all the latest updates.

You can view your sponsored frame photographs (updated every 6 months) as part of our Maldives resorts Coral Frame Collection.

‘Junior Marine Savers’ photos: (1) Transplanting a Reefscapers coral frame; (2) feeding turtle hatchlings.

Junior Marine Savers activities

Our Unreleasable Turtle Residents

Our Current Turtle Patients

Our Juvenile Turtle Patients

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