This week in Lembongan… Usually during the dives in Crystal Bay, the large central sand patch is quickly crossed by divers who go from one side to the other, spending most of their time on the coral areas, and used by students taking courses because of the ease to kneel and demonstrate the skills sheltered from current and without harming the marine life. Well, they should consider spending more time there because there’s a whole specific ecosystem around!
This week in Crystal Bay, we decided to explore the sand patch and the canyon, and we’ve seen plenty of life… there’s of course the obvious ones, like goatfishes, who keep on probing the sand with their barbels to find food – they feed on worms, crustaceans, molluscs and other small invertebrates. You can also spot lots of juvenile three-spot dascyllus on the little coral and anemone patches that are scattered on the sandy area of Crystal Bay. They are very recognizable with their black color and three white spots.
Schools of striped eel catfish are also often spotted on the sand. They are amazing to watch when moving around, although don’t put on hand on them; their first dorsal and each of the pectoral fins have a highly venomous spine. They may even be fatal!
There are also lots of types of blennies and gobies, amongst them, dartfishes, which will hide in the sand as soon as you approach too closely.
Some other animals are way less easy to spot, because they use mimetism to hide in their environment: the flounders are very good examples of this behaviour. Flounders are flat fishes with skin colour and patterns very similar to the sand, with variations looking like the grains. Some of them are almost impossible to spot unless they are in movement!
The evolution of flounders is quite interesting: in its life cycle, at hatching one eye is located on each side of its brain like the majority of fishes and it swims in a vertical position. As an adult, a flounder changes its habits and camouflages itself by lying on the bottom of the ocean floor as protection against predators, and two eyes situated on one side of its head… One eye migrates to the other side of the body as a process of metamorphosis as it grows from larval to juvenile stage, so as a result, the eyes are then on the side which faces up! The side to which the eyes migrate is dependent on the species type.
And there’s plenty more to see, so don’t hesitate to spend a bit of your bottom time on the sand!