Marine Aquaria at Kuda Huraa
With the help of Aku, our resident fish expert from from Landaa Giraavrau, we added new fish species to our 2 tanks, including:
– zigzag wrasse, Picasso triggerfish, yellowhead butterfly fish, saddled toby, leopard flounder, cleaner wrasse.
The light setting cycle was adjusted to give brighter daytime hours, followed by evening soft blue light and then off overnight. This will allow the fish to rest at night and give coral the light they need during the day. Rocks were also added to increase the complexity of the tank and create more hiding places for fish and surface area for corals.
The soft leather coral (Sarcophyton trocheliophorum) has been wedged in between the large rock on the left side of the aquarium, and it is now looking much healthier. New corals have also been added, including Pocillipora damicornis, Fungia sp., Leptastrea sp. and Galaxia fascicularis. The Montipora digitata colony was replaced with a new specimen, as the old one was suffering from Drupella snail predation.
A coral plate was added at the start of the month, to study fragment growth of different Acropora species (Acropora digitifera, Acropora cytherea, Acropora intermedia).
Above: junior Marine Savers learn about our aquaria
Left: aquarium 1 (top) and aquarium 2 (bottom)
Reef anemone health assessment of Baa Atoll
Our health assessment around Baa Atoll is continuing, designed to increase our knowledge of wild Maldivian reef anemones. Since November, we have collected data for 76 anemones sighted across 10 different reefs.
This month we recorded 13 new anemones (7 in ‘good health’, 5 ‘nearly bleached’) including the first fully bleached specimen, spotted at Finolas reef. Species recorded included Heteractis magnifica (6), Stichodactyla mertensii (6) and Entacmea quadricolor (1).
We now have data from a total of 76 anemones from 10 different reefs. All our data will be shared with the Naifaru Marine Centre, which is working closely with the Australian ‘Saving Nemo’ organisation.
Map of Baa Atoll with plots of recorded reef anemones
Our dataset of wild reef anemones is growing
Ornate eagle ray (Aetomylaeus vespertilio)
A few weeks ago, Hussain Suja (our colleague from the Water Sports team) was incredibly lucky to spot a rare Ornate eagle ray, right here in our shallow lagoon at Landaa! Hussain kept his cool and was able to fire off a couple of photos to share with us.
The Ornate eagle ray (Aetomylaeus vespertilio) has not been sighted in any significant numbers since its scientific classification more than 160 years ago. It is listed as “endangered” by the IUCN, with a declining population due to fishing pressure and low fecundity. According to some local Maldivians, this is a once in a lifetime sighting!
We noticed the Wikipedia entry was missing an ID photo, so we were pleased to submit our own image for inclusion.
Aetomylaeus vespertilio has a maximum size of around 240cm in disc width, and a clearly distinct pattern of reticulate dark lines and rings on its back. If the extremely long tail is unbroken, it can considerably add to the maximum body length of 4m. They are estimated to have a low fecundity similar to other myliobatids. They have a generation length of 15 years, and can grow as old as 24 years. Lacking spine on the tail, it is deemed harmless to humans. Source: Wikipedia
Ornate eagle ray (Aetomylaeus vespertilio) Baa Atoll, Maldives
Thanks to Hussain Suja (Water Sports) for the great photos!
Fish Lab population
February was a good month in the Fish lab, with our Maldivian Clownfish (Amphiprion nigripes) breeding pairs laying quality eggs. Using our special rotifer food (enriched with microalgae and S-presso) continues to give good quality larvae (confirmed under the microscope) and subsequent improved survival and growth rates.
The production of our live foods (phyto and zooplankton) is at its peak:
• 300L Artemia as Seahorse food.
• 80L Rotifers (one bucket enriched with 18L of micro-algae)
• 1200L of micro-algae (300 L less than January).
We also donated 5L Nanochloropsis and 1L Rotifer to the Naifaru centre, to help them start their breeding programme.
This month we released 10 clownfish and all 7 anemones from the bisection programme. To create an anemone garden, we have repurposed an old coral frame into a new cage, to keep the anemones in one place and to reduce predation of our captive-bred fish. The experiment is going well, and all the fish and anemones are still alive at the 2-week stage.
Above: Our apprentices help with Clownfish tank cleaning
Above: Clownfish release day
Right: Biodiversity assessment before Clownfish release
Clownfish protective cage, made from a coral frame
Clownfish released into lagoon under protective cage
On 26 February, after several days of courting and dancing rituals, our seahorse dad successfully gave birth to 58 babies! In the wild, the young seahorses must care for themselves and there is a very high mortality rate (99%+). We hope to raise these juveniles for a few weeks and then return them to the wild.
Around the same day, our Frogfish also exhibited some strange behaviour, as it became swollen and was seen floating at the water surface … and then started to spawn!
Baby seahorses in our Fish Lab at 1-day old
ABOVE: Sargassum frogfish (Histrio histrio)
LEFT: Sea horses (Hippocampus kuda) eating Artemia shrimp
Baby seahorses (1 & 3 days)