Fish Lab, Aquaria, and Marine Life in the Maldives

Plankton Production

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

– Microalgae (Nannochloropsis) – Overall, 400L of algae were produced throughout the month, useful for our newly hatched clownfish larvae.
– Rotifers – Population density has been mostly stable throughout this month with an average of 461 ind./mL (above our target concentration of 300 ind./mL). As population density was constant, food quantity per session has been kept to 2mL of Nannochloropsis sp. microalgae, given 3 times a day.
– Brine shrimp (Artemia) – Same protocol as last month, two separate batches were raised daily, for feeding: (1) jellyfish, shrimp and fish; (2) settled coral polyps from the spawning collection last month. Both batches were supplied 3g of brine shrimp per day throughout the month.

Fish Lab Breeding Programmes

• Moon Jellyfish (Aurelia aurita) – populations remain healthy.
• Groupers (Epinephelus fuscoguttatus) – By the end of the month, a total of 466 individuals are still thriving in the facility. Average daily food increased from 1.7kg (last month) to 2.3kg; individual daily consumption increased from 3.6g/day to 4.9g/day.
• Clark’s anemonefish (Amphiprion clarkii) – our November batch individuals have now grown into the juvenile stage. Technical issues came as the air pump providing oxygen to a majority of the tanks (6-10 and 16-20) turned off multiple times for very long periods of time as water flow is switched off to avoid loss of larvae. Dimmed light was still activated for the first two weeks until all larvae were capable of feeding on 1 day-old Artemia. [Lifecycle graphic]

Aquaculture – ‘seaweed’ as sustainable foods

• Sea Grapes (Caulerpa racemosa) – To expand production, we harvested a new batch of sea grapes from Kihadhoo on 12 December. This batch was added to our outdoor tank #7 along with sea moss, and later moved to our blue tanks. We continue experimenting with small trays to encourage faster growth, checking for potential grazers that might be feeding on our sea grapes crop! In total, we supplied 2.2kg of seagrapes to the Kitchen this month – a new record!

  We have also received a smaller variety of sea grapes from Japan. These are now in a 100L tank close to tank #7, with water flow supplied directly from our grouper tank to provide natural nutrients. Unfortunately, most of the culture died.

• Elkhorn Sea Moss (Kappaphycus alvarezii) – this month, we received a 5kg batch of a new red tropical algae that contains a high level of carrageenan, used as a food-gelling agent. In the lagoon, we set up two 20m-long rope lines arranged as rectangles, fixed with metal rods, and attached branches of macroalgae every 30cm. Unfortunately, after just a few days, most of the elkhorn sea moss had been eaten by fish!
  In a different setup, we attached some macroalgae branches on short 1m ropes in our 1000L tanks, with incoming water circulated from the nutrient-rich grouper tank. This batch of elkhorn sea moss is looking healthy so far, but hasn’t yet started to grow.

Guest Excursions

At Landaa Giraavaru, we conducted 28 guided tours of our Marine Discovery Centre for a total of 103 guests. Our guided snorkel excursions were enjoyed by 206 guests. Across 10 separate Dolphin Cruises for 115 guests, we recorded sightings of 370 Spinners plus 40 Bottlenose dolphins, the latter in an amazing courtship encounter!

At Kuda Huraa this month, a total of 252 guests enjoyed 46 different excursions to 5 different underwater sites in the area, where we recorded 12 different megafauna species.

Junior Marine Savers

We hosted a record number of 15 Junior Marine Savers during December. Each session is filled with learning about different species, including turtles, coral and cetaceans, and then followed by relevant activities such as turtle feeding, coral frame building, or helping to identify dolphins on the computer! Then comes a special guided snorkel trip, where we visit the sunrise side channel and to spot and identify all the different marine creatures we encounter. Sometimes we are lucky enough to see sharks, turtles, rays… accompanied of course by huge smiles on the kids’ faces! It is always a pleasure teaching the next generation not only how impressive our natural world is, but how imperative it is that we protect it. Now they can go off and tell their peers to respect our planet, making this world a little bit better each time!