Fish Lab & Marine Aquaria
Common clownfish (Amphiprion ocellaris) laying eggs in our Fish Lab
Plankton Production
- Algae – production is continuing at half capacity (since April) due to low requirement (no Clownfish larvae to feed).
- Artemia – we have increased the production of Artemia (day 1) to feed the new main aquarium arrivals, and we continue to grow-on Artemia for the sea horse and Clownfish breeding pairs.
- Rotifers – we have had problems with build-up of ciliates, which reduced the Rotifer concentrations to as low as 130/ml. After investigation, we discovered the ciliate build-up is mainly caused by our dried yeast food. Nannochloropsis (micro-algae) is a good food source for rotifers due to the high lipid, protein and calorie content, so we have now reduced the yeast and started using an auto-dosing feeder to dispense 20ml Nannochloropsis every two hours. The combination of the two food sources has resulted in better quality rotifers, with much less ciliate contamination. Concentrated Nannochloropsis is the accepted optimal feed (minimal water quality changes, high concentration of nutrients), which we plan to start using in 2021.
- Photo below : ciliate / ciliate / Rotifers + eggs
Large Aquarium
We have some new additions to our main aquarium, including basslets, cardinal fish, wrasse and damsels, in addition to some new soft and hard coral specimens. Both pairs of anemone fish are spawning regularly, and the eggs lasting full term.
Small Aquarium One
- Mini coral frame – only five coral fragments remain healthy.
- A new Galaxea astreata specimen was introduced (photo, below); it is growing well and not displaying signs of stress.
Small Aquarium Two
- Mini coral frame – overall healthy and encrusting, although a few fragments show signs of stress.
- Clark’s anemonefish (Amphiprion clarkia) and Blue Damselfish continue to lay eggs.
- A new mushroom coral was introduced; it has settled in and started to grow.
Linckia multifora sea stars
- SS1 (large specimen) – affected by disease or parasitic infection, and likely will not survive.
- SS3 (large specimen) – the arm that detached in April continues to grow well.
Jellyfish – Aurelia aurita
We now have 5 tanks of growing jellyfish:
(1) polyp tank #20, (2) small-jelly Kreisel, (3) a medium-jelly Kreisel, (4) a large-jelly Kreisel, (5) main display.
All the water is now being UV-sterilised and changed every three days, resulting in much reduced growth of algae (especially noticeable in the main display tank).
By the end of October, we totalled 1360 jellyfish, with tens of thousands of polyps ready for strobilation [*]. We are currently investigating tank designs, and might start to sell our Aurelia to hobby aquarists in the Maldives (international prices are $20- $70/jellyfish, dependent on size).
[*] Strobilation is defined as asexual reproduction by transverse division of the body segments which develop into separate individuals.
REEFSCAPERS Coral Propagation Program
Monthly Progress – November
At Landaa Giraavaru this month, we transplanted 8 new coral frames, and monitored (cleaned, maintained, photographed) a further 201 existing frames at the Blue Hole and Water Villas sites.
At Kuda Huraa during November, we transplanted 7 new coral frames, recycled 1 old frame, and monitored a further 183 frames (mainly at the Water Villas site).
Check out our 2020 Diary for further project details and all our latest photographs, including a report on coral spawning, with updates on our autonomous AI coral ID project and our new scientific research paper entitled:
“Coral restoration provides a consistent increase in live coral cover on the reef over time”.
Sea Turtle Conservation
On 20 November, we received a call from the island of Asdhoo (N.Malé Atoll) reporting some stranded hatchlings.
A total of 55 Green turtle hatchlings were sent to us; following a thorough health check, most were released into the ocean.
Eight of the hatchlings were admitted for care and treatment at our Centre (3 hatchlings were very lethargic, 5 hatchlings have a carapace deformation [an extra scute]).
These new additions join our 17 recently admitted Hawksbill (Eretmochelys imbricata) turtle hatchlings, from two separate nests, who have now settled in and are able to dive down in their pools for food. They are largely healthy, but we are treating them for minor eye infections, and have separated them into two pools to avoid aggression.
See ‘Our Turtle Hatchling Patients’ section below, for photographs and more details.
At the end of November, we had a total of 6 Olive Ridley turtles (Lepidochelys olivacea) rehabilitating at our turtle rescue centres.
Environmental Enrichment Project – sea turtle rehabilitation
Our ongoing behavioural study is progressing well. We introduced a series of novel environmental enrichment devices (EEDs) into the pools of our long-term (unreleasable) turtle patients, and filmed their subsequent behaviours. Different objects acted as ‘toys’ (frame, ball, brush) to stimulate each animal’s curiosity to novel objects and for tactile stimulation. To stimulate foraging/hunting behaviours, food was delivered on a rotational schedule using different strategies (fish ‘popsicles’, PVC pipes, floating lid). We also continued our regular ocean swims with each patient, out in the Resort’s lagoon.
For the next stage, we need to characterise the behaviours of the turtles both with and without the enrichment. Twenty-minute video clips were recorded for all four patients, without enrichment, and again with 6 different devices in turn.
Ethograms (behaviour catalogues) were created to evaluate the effectiveness of the enrichment devices. Using continuous sampling, the footage was evaluated by timing the different behaviours:
- repetitive pattern swimming,
- focused/oriented behaviour (interaction with the device and grooming),
- random swimming around the pool,
- resting on the water surface.
- Without enrichment, the turtles spent most time ‘pattern swimming’ (75%) and ‘resting’ (20%), and very little time ‘oriented’ (<1%).
- With enrichment, ‘pattern swimming’ (40%) and ‘resting’ (1%) were much reduced as expected, with more time spent ‘oriented’ (40%) towards the devices and ‘random swimming’ (20%). This behaviour shift was consistent for all 4 turtle patients, although variations in behaviours towards the different enrichment devices was recorded, due to their different personalities.
The results of our pilot study show that environmental enrichment can be effective in increasing activity and exploratory behaviours in captive sea turtles. A changing environment provides turtles with the opportunity to make behavioural choices based on the assimilation of new information, and the ability to satisfy curiosity about new stimuli. Because of this, it is important to maintain novelty, which can be achieved by providing enrichment for short periods in rotation (as inquisitive initial behaviours may lessen with familiarity). The varied responses seen between the turtles serves to highlight the importance of tailoring enrichment devices to each turtle’s preferences.
Overall, positive behavioural changes were seen in all four turtles, so we will continue to develop and implement enrichment devices to improve the psychological and physiological well-being of our rehabilitation patients.
Pictured below, interacting with their environmental enrichment ‘toys’: Frisbee – Varu – Thaku – April
Maldivian Sea Turtle Identification Program
Turtle photographs are kindly sent to us from members of the public, fellow marine biologists and dive centres stationed at other resorts around the Maldives. 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.
During November, we received 12 sets of photos from the public towards our turtle ID project.
Spotted a turtle? Share your photos
Green turtle #CM214, from our ID database of Maldivian turtles
Meet Dafne Limón, a 31 year-old veterinarian from Mexico City. She joined Marine Savers team in March 2020 as the very...
Posted by Four Seasons Resorts Maldives on Thursday, 26 November 2020
Shakti was successfully tracked via satellite for 105 days!
With the weather changing, there is a greater chance of turtle strandings and entanglement. Please keep your eyes out...
Posted by Marine Savers on Friday, 6 November 2020
Further News & Updates
You might also be interested in our Dolphin ID Project, and our Sea Turtle Enclosure out in the lagoon at Landaa.
Looking for details of our coral propagation programme ?
Head over to our Reefscapers 2020 Diary for all the latest updates.
You can see how your sponsored frame grows by viewing our photo updates every 6 months, as part of our unique Coral Frame Collection.
Photos: (1) Reefscapers coral frames at Kuda Huraa water villas.
(2) Junior Marine Savers learn the importance of corals.
