Экспедиция JBL 2018 - Индийский океан

Underwater feeding on what is probably the most beautiful island in the world

Our neighbouring island La Digue is considered to be the most beautiful island in the world. On a day trip we wanted to see for ourselves and take the opportunity to feed the reef dwellers with the food prototypes and JBL MariPearls we had brought along to observe their reactions.

Do reef dwellers eat aquarium fish food in the wild?

It is always exciting to watch how fish that have never been fed a food before react when they are offered aquarium fish food. Sometimes they are so greedy that they almost swim into the tin…

On a tour of the island we learned how coconuts are processed and how oxen are used to produce coconut oil.

Even after 13 expeditions it’s still fascinating to see how much the participants love animals. The guide might be giving the most interesting cultural explanation in the world, but the minute a spider or a millipede is sighted, the group have all gone.

Not even the venerable villa with historic furniture had a chance against the Aldabra giant tortoises.

At the end of the La Digue visit there was still some work to do. Water tests were on the agenda. In the 30 °C warm marine water the conductivity was 53.9 mS/cm, the carbonate hardness was 9 °dKH, the pH value 8.3, the magnesium content 1300 mg/l, the calcium content 380 and the density 1.025.

However, due to the waves, the beach was not suitable for measuring the photosynthetically active radiation (PAR) above and under water.

The paradise beaches of the Seychelles

After the work is done, it is simply beautiful to enjoy the clear, 30°C warm waters of the Indian Ocean and to look back on all our impressions. You never know if you’ll ever be back this way again. And besides, there are still those mudskippers in the brackish water…

On a more tranquil beach the three of us were able to carry out the PAR measurements. One held the folding rule to read the water depth, one held the PAR measuring device in the waterproof cover and read the value, and one wrote down the values.

Since many corals contain endosymbiontic algae in their tissue and live in shallow depths, photosynthetically active radiation is certainly important. Blue aquarium lighting looks nice and emphasises fluorescent effects, but does not necessarily promote coral growth. Above water the PAR value is 1925 µmol/sec/m2. Directly below the water surface the PAR value drops to 1750 due to the reflection. At a depth of 10 cm it is 1200, at 20 cm 1010, at 30 cm 840, at 40 cm 670, at 50 cm 650 and at 60 cm only 550 µmol/sec/m2. By the way, the Seychelles are also home to some very nice day geckos. They can be found on almost all islands of the region, not only Madagascar!

On the last day before our departure we wanted to have a look at what is probably the most famous nut in the world: the Coco de Mer. It only exists on the Seychelles island Praslin and is under the highest protection. It's really funny that the female nut resembles a female lap, while the male flower ...well...looks exactly the same as…

These adventures brought the 13th JBL Expedition to an end. We were able to observe plenty of interesting animals, were thrilled by the natural environment and disappointed by the guides in Madagascar. The Seychelles above water inspired everyone to want to come back with their family or friends. But the marine fauna was only average. At the Maldives or at Zanzibar we had already studied more spectacular reefs. Measuring the various factors brought home to a lot of us how much there is still to learn about the natural habitats of our aquarium and terrarium pets. And this is exactly why we are going on an expedition again. Will you join us next time? You just have to be as fond of animals as we are. Then you’re one of us…