Caught in the act! Corals releasing colourful eggs into the water during a mass spawning event.
Erin's Monthly Marine Musings
Another glorious month – some unpredictable daytime weather, with nights spent in an underwater blur of coral spawning work. Everyone stepped into multiple roles, and we crushed it! With coral babies growing back in our Lab, and rescued turtles healing out front, we’re stoked for the festive season ahead!
- Now deep in ocean sunk the lamp of light, and drew behind the cloudy vale of night. — Homer
Fish Lab & Aquaria – Marine Life in the Maldives
We gave our large 4000L display aquarium a deep-clean during November. Debris was removed from the base, the three pumps were cleaned of accumulated CCA and algae, and any dead corals were removed, replaced and rearranged.
Plankton Production
- Algae supply remains good, on a consistent and successful cycle.
- Artemia production is keeping up with the demand of the main tank, at 6g of cysts a day. Production has moved outside, and the new batch of cysts are hatching more successfully than the previous batch.
- Rotifer volumes remain consistent and stable, despite a slight dip in the middle of the month.
Jellyfish – Aurelia aurita
Unfortunately, during a water change this month, there was a loss of jellyfish from the small Kreisel tank. The survivors have since recovered and are doing well. In the main display cylinder, all specimens are healthy and growing (no signs of shrinking) and the new UV steriliser is working well.
Zooplankton Survey Study
As part of our Zooplankton Survey, our new closing plankton net has arrived and is being trialled. There are several modifications that need to be made to the net for it to work effectively.
Guest Excursions
Our most popular guest excursion by quite a margin is the Dolphin Cruise, followed by the Turtle Safari, and we ran the full range of tours this month (Guided Adventure Snorkel, Shark Safari, Marine Life Safari).
Participation totals for November were 140 guests at Kuda Huraa, and 210 guests at Landaa Giraavaru (which includes Landaa’s popular Marine Discovery Immersion Tour).
During November, we recorded an in increase in tiger shark numbers, with several exciting encounters at quite close range (5m, rather than the more usual 45m distance).
flatworm spotted swimming on the reef
pipefish on the reef
magical Mantas
Ornamental Fish Breeding
Our focus is to produce replicable and consistent data for our research paper on Thor amboinensis, and to continue tracking and describing the reproductive cycle of Lysmata amboinensis.
- Clark’s clownfish (Amphiprion clarkii) – There were two spawning events in November, but the eggs were again eaten by the parents prior to hatching. We have attempted to vary the parental diet to prevent this, but with limited success.
- Maldivian clownfish (Amphiprion nigripes) – No spawning events again this month, so we moved the breeding pair from tank #21 back into the main display aquarium, where they have already started to demonstrate nesting behaviours.
- Sexy shrimp (Thor amboinensis) – Two clutches collected this month, giving a total of 469 larvae. There are now 21 larvae from our October batch in the final stages of development, with five larvae settled into the juvenile shrimp stage (now introduced to the display tank). Our new protocols are working well for these final-stage larvae, to promote faster and more successful settlement.
- Boxer shrimp (Stenopus hispidus) – Two clutches produced this month, and left to hatch without collection. Our observations continue on the reproductive cycle and ovarian development.
- Camel shrimp (Rhynchocinetes durbanensis) – The four larvae from September continue to do well, and are in late-stage near-settlement (based on features observed in our other species). There is currently no standardised full larval description for this species, so it is difficult to assess how many stages they have left before settlement. Currently, all four larvae have fully developed uropod structures and swimmerets in the form of biramous buds, which in two of the four have developed into larger structures (similar to stage 6/7 of Thor amboinensis).
- Skunk cleaner shrimp (Lysmata amboinensis) – We have collected several batches of larvae this month, to trial our new protocols, that gave various degrees of success. Last month’s clutch continues to develop, with two larvae remaining. A focus for this month has been on tracking the reproductive cycle and ovarian development. This species is a simultaneous hermaphroditic shrimp, and there is limited understanding of its timings and process of reproduction. This month, we have observed three reproductive events, with a clear track of intermolt periods and development of the ovary.
Development of larvae in Sexy shrimp eggs (T. amboinensis)
Development of swimmerets in Camel shrimp (R. durbanensis )
Outreach – Fuvahmulah School Visit
This month, we welcomed 40 enthusiastic A-level students from the Atoll Education Centre in Fuvahmulah for a session at our Marine Discovery Centre. This included informative talks on our marine conservation projects, followed by a coral frame building session. The students were passionate and deeply knowledgeable about the marine environment, which shone through in their questions.
Maldives Sea Turtle Rescue & Rehabilitation
Oceans swims out in the lagoon …
… are important for rehabilitating sea turtle patients
At the close of November, we were caring for three Olive Ridleys (Lepidochelys olivacea), one Hawksbill (Eretmochelys imbricata), and zero Green sea turtles (Chelonia mydas) in our Rehabilitation Centre at Landaa.
At Kuda Huraa, we continue to care for Emma, found in October floating on the ocean surface with a missing flipper. After surgery, she started to become a fussy eater, and is now much less active in her recovery pool. We have started a new round of antibiotics, and we are monitoring her health closely (see Instagram, below).
Our long-term Olive Ridley patient Ari remains popular with guests and staff. She has been downgraded to a smaller pool since Emma’s arrival. Ari enjoys eating seagrass when she is out on her ocean swims, but for some reason does not eat it while in her pool (we even attempted a seagrass ice block, but she was not interested at all!)
Ocean Enclosure
Pepe was successfully rehabilitated in our large ocean enclosure, where she soon started diving and resting on the bottom netting. She was released on 29 November [see Instagram video, below] and the pen is now home to Artemis in the hopes that the extra space and water depth will encourage more diving behaviour.
Bethany, our turtle biologist, performing a weekly health check for Ari, at our rescue centre, Kuda Huraa
Kat, our resident turtle veterinarian, assessing progress of turtle patient Maw, during a rehabilitation ocean swim
Maldivian Sea Turtle Identification Program
During November, from the 10 new photo sets submitted by the public this month, we were able to add 5 new individuals to our national turtle database, and confirmed resightings of 1 named turtle already in our database.
EI1213 named ‘Ginger’ has been spotted around Kuda Huraa since 2019. She was in the Blue Hole every night during coral spawning monitoring this month!
Our current database now has uniquely identified totals of:
1377 Hawksbills, 294 Greens and 97 Olive Ridleys (from 5400+ separate sightings, across 17 different atolls of the Maldives).
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.
REEFSCAPERS Coral Propagation & Reef Restoration in the Maldives
Checking for the presence of coral gametes
Coral bommie mapping
Monthly Progress
At Landaa during November, we transplanted 19 new coral frames, kindly sponsored by guests (8), the Resort (8), and online (3), using a total of 901 new coral fragments. In addition, we monitored 530 coral frames at various sites around Landaa Giraavaru.
At Kuda Huraa, we transplanted 7 new guest coral frames, recycled (cleaned and retransplanted) 2 old frames, and monitored (cleaned, repaired, photographed) a total of 141 frames around the island.
Read our Reefscapers Diaries for further details and photographs of our ongoing coral propagation efforts and reef regeneration experiments, both in the Lab and out in the lagoon, updated each month.
The big news this month was of course the fantastic coral spawning event that we were lucky to be able to witness, photograph and study at very close range!
In our brief time-lapse video captured in close-up by Simon (our Centre Manager), you can see the exact moment that a coral polyp releases its bundle of gametes (eggs & sperm) into the ocean.
In our photos, various coral species are shown at the ‘bundling’ stage, with brightly coloured gametes ready for synchronised release … such an incredible spectacle! And well worth the hours we spent in the lagoon each night, around November’s full moon.
Reefscapers Maldives Acropra coral bundling
Acropra sp. bundling
Reefscapers Maldives Acropra corals bundling
Acropra sp. bundling
Reefscapers Maldives A.secale coral bundling
A.secale bundling
Reefscapers Maldives A.plantaginea coral bundling
A.plantaginea bundling
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 (launched in 2021).
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.
