JBL expedition back from viewing the largest aquarium fish in the world

Due to their size of over 10 meters whale sharks aren’t exactly the ideal aquarium inhabitants. This doesn’t stop more and more public aquariums worldwide, from Atlanta/USA to Taiwan, from keeping whale sharks in aquariums. The JBL expedition team travelled to the north of Madagascar to see the behaviour of whale sharks in the wild and came to the conclusion that while their nutrition in the aquarium may not be a problem, the aquariums, no matter how big they are, always constitute a tiny prison space for them.

Then we went to the central rainforests of Madagascar to take a closer look at the biotopes of the legendary chameleons, day geckos and frogs. The most important finding was that the humidity and temperatures vary enormously: from 29.4 °C with 59 % humidity at noon at 12:30 to 19.8 °C with 98 % at 21:30 in the evening. The habitats with these strongly fluctuating parameters were apparently ideal for an unbelievable abundance of animals. Accompanied by the screaming of the lemurs, the participants found many frog and chameleon species, all the day gecko species with their habitats there, turtles and two snake species. We actually found the standard guides of the national parks, which were targeted towards the average tourist and either took the form of a tour through the jungle in search of prosimians, or a sensationalist attempt to create attractions by means of previously positioned chameleons, more a hindrance than a help. In Mauritius, we focussed on marine habitats. A comparison with Madagascar showed a lower biodiversity and also a scarcity of corals which could not be explained by the marine water parameters: Only the magnesium content of the marine water, at 1220 mg/l, was slightly lower than that of Madagascar (1340 mg/l) or the Seychelles (1300-1400 mg/l). The two wrecks Emily and Water Lilly, which sank in 1981/82 and are now resting on sandy soil at a depth of 25 m, also showed a correspondingly low growth of stony corals. The Acropora corals growing on the ship's wall had grown to only 40 cm in the past 37 years. In other places and in the aquarium the growth is higher to the factor of 10! At the end of the JBL expedition, the team travelled to the Seychelles, just below the equator. Above water islands looked absolutely fantastic, but were generally barely average under water. Although the coral growth and biodiversity were significantly higher than in Mauritius, they are nowhere near the diversity level of the Maldives, which lie only 2000 km northeast in the same ocean. This JBL expedition made it clear that marine diversity cannot be determined by water values, it depends very much on geographical conditions. The Caribbean is clearly species-poor, the Indo-Pacific region has the most species in the world, and the extensive regions of the Pacific (South Sea) are very species-poor.

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