(02-11-08) During our long journey through the seas in Indonesia we dive into the dark waters of the Lembeh Strait, which is a home for strange creatures that walk over black volcanic sand. This is an unreal world; it is the result of pollution and currents, where fishes do not swim: they walk.

   Once again we are guided by our friend Miguel Fuster, from Atlantida Sub. We are going to dive into the waters of the Lembeh Strait. This is a channel almost 2 km wide and 16 long, which separates Sulawesi from Lembeh Island. It is very close to the equator, in the centre of the seas of Indones

   Carrying our camera and Deep Blue-Video equipment, we are going to discover an unreal world during our dives for filming a documentary. It is very different from what is normal in the equatorial reefs, which are always full of colour and life. We are witnessing a sort of "dark" paradise for divers, recognized as the epicentre of the muck diving on Earth.

   The pollution in the Strait is due to large populations and industries that dump their waste into the sea directly, besides the intense maritime traffic. Because of this pollution Lembeh has become a place with dark and cloudy waters, with beaches and black sand floors as a result of its volcanic origin.

    There are no large coral formations, or the exuberant life in the reefs in this hostile environment. It seems a dark, desolated and seemingly uninhabited world... But it is not true at all. In this unattractive habitat we find the strangest creatures -most of them drag over the floor-. They are animals that only exist in this area in the world. The underwater life in Lembeh Strait is as extravagant as sophisticated.

learning to "see what you look at"

    But, the first thing to learn in Lembeh is how to look and see. The first impression is that there is nothing, only dark soil and sediments. We have been told that there are “walkers” that have adapted themselves to the environment ... Suddenly, we discover some penetrating eyes watching us: it is a hermit crab hidden in its shell. We learn the first lesson about why the camouflage is essential to survive here.

    We get used quite soon to think that every thing that looks like a leaf, a stone, a polyp, a coral, a sponge ... can be a fish. It is understandable why the creatures of the Strait have had to evolve their dorsal and pectoral fins to walk or run rather than to swim. The answer is that most of the food they can find is in the semi-dark and rocky substrate in the bottom of the sea.

    One of the most striking fishes (which allowed us to film and, almost, interview it) was something like a bird Pegasus. It is known as dragon fish. It has developed their dorsal fins as if they were the wings of a bat, and the pectoral fins are like small legs with fingers that the fish uses to move itself.

    There are very few places for hiding, but the fish has got adapted to its environment by changing the appearance of its skin. It copies the colour and texture of the soil. The fish can turn over the bottom of the sea as expert to find all the food. If it feels threatened, it stands still until it is almost impossible to make it out from the environment: it means a good camouflage that increases its chances of survival.

LETTING THE CURRENT ROCKS THEM

    Another common species in Lembeh that can go unnoticed is the leaf fish. These fishes can stand still, letting the current rocks them, as if they were old leafs: their heads down, in an oblique position to the bottom and volcanic sand.

    Only when it moves (jumping, driving itself by its dorsal fins) one can see that it is a real fish. Either on the sand, or among the rocks, it always knows how to camouflage itself, and how to be integrated in the environment. We meet a specimen covered with algae that, being rocked by the current, was patiently waiting for small fishes to open a gigantic mouth and suck the prey in a millisecond.

    As its name suggests, the body shape looks like a piece of tree or bush, and we have seen it changing its colour depending on its state of mind. It has become the same colour a dead leaf is: yellowish or reddish-brown tipped. From the eye to the "tail" there are three black thin lines that imitate the nerves of a leaf.

    A mantis shrimp appealed to us. It passed some big sea urchins while it was escaping. The sea urchins “walked” surprisingly fast. These invertebrate animals, such as starfish and sponges, do not have a respiratory system. They capture oxygen directly from the water by diffusion.

VIBRANT DAMSELFISHES IN A DARK WORLD

    Among its spins, we find damselfishes dancing. They feed on plankton that the covers sea urchins and, incidentally, are properly protected from predators, despite their flashy moves.

    We meet strange beings all the time. Sometimes the animals surprise us because of their speed: it is again another clear example of their adaptation and camouflage. The fish needle stick, which moves on the belly as fast as a snake, is always perfectly mimicking with the background.

    However, there is always something that comes out of the rule. We realized it when we meet a worm fire in the middle of nowhere. It was quietly looking for its food on the bottom.  It was making a spectacle of itself, and seemed it didn’t need to hide from predators... Its “arrogance” is possible thanks to a lethal weapon that protects it: two rows of fine poisonous needles that are in its body.

    Another exception to the rule is a fish that travelled swimming! The horse mackerel fish (which looks like a futuristic helicopter) is one of the few fishes that swim in these waters. It does it very elegantly, displaying its spectacular dorsal fins as if they were wings. The edges of the fins are covered with fearsome poisonous quills. This species uses its tail fin as a powerful and directional driving, and the pectoral fins serve as a "landing gear" and to move jumping, “gliding” over the bottom.

    After a long diving, walkers in Lembeh have shown us clear and striking examples of adaptation. These strange sea creatures live in a place where the ability to go unnoticed is essential to survive in a desolated environment where food is scarce and they have to compete for it.

Documentary “Los caminantes de Lembeh” available in www.deepblue-video.com

Text and photo: Jorge Keller - Deep Blue-Video