Black Moray Eel – Muraena augusti
The Black Moray Eel is a species in the order of the Anguilliformes and is therefore a species in the order of the superclass of bony fishes. Muraena augusti was first described in 1856 by Johann Jakob Kaub.
Description, Anatomy & Characteristics
The Black Moray Eel has an elongated, snakelike body. Their basic colour varies from dark blue to violet, almost black. In addition, its body is dotted with small, widely scattered white and black spots. The bright white eyes of Muraena augusti are really striking.
The Black Moray Eel grows up to 120cm long and weighs almost 2kg.
Their mouth cleft is large, long and reaches behind the eyes. In addition, four pronounced nostrils in the form of small appendages can be seen between the eyes and mouth.
Habitat & Distribution
Muraena augusti lives in rocky reefs, crevices, holes and caves. It occurs in depths down to 250m.
While diving on the Canary Islands you can observe the Black Moray Eel on almost every dive. It is by far the most abundant species of the moray eel family in the Canary Islands.
In most sources only the islands of Macaronesia are mentioned as their distribution area. These include the Canary Islands, the Cape Verde Islands, the Azores, Madeira and the lhas Selvagens. According to http://species-identification.org/, however, it can be found throughout the North-East Atlantic from Senegal to Great Britain and also in the Mediterranean Sea.
Biology & Feeding
The Black Moray Eel is almost exclusively nocturnal, even if you sometimes see it outside its hiding place during the day. They spend most of their time in daylight in holes, crevices and caves and only leave their shelter at nightfall to catch prey. They are looking for different shrimps, cephalopods and small fish.
Besides, they’re territorial. Often the same animal is found in exactly the same place over a long period of time.
If you find the Black Moray Eel during the day, you can often observe it opening and closing its mouth. This is mistakenly understood as threatening gestures. Due to the missing gill cover, they only pump fresh water through their gills in this way. When moray eels really threaten, their mouths are open all the time.
Symbiosis with Cleaner Shrimp
Since you see the Black Moray Eel quiet regularly, you have a good chance to meet it with its friend, the Scarlet-Striped Cleaning Shrimp. Both species together give us a special insight into the coexistence of different species underwater. Lysmata grabhami, the scientific name of the Scarlet-Striped Cleaner Shrimp, cleanses the skin and teeth of the moray eel. It simply feeds on the remains of the skin, the food between the teeth and any parasites. In return, the Black Moray Eel is clean and free of parasites.
The Monaco Shrimp also shows this behaviour in the presence of Muraena augusti, but is much rarer to be found.
In the Canary Islands, Muraena augusti reproduces between May and October, reaching its peak in August. The eggs are fertilized in the water and then float in the plankton. When hatched the larvae also drift with the plankton until they reach a certain size and settle on the seabed.
The Black Moray Eel becomes sexually mature with approximately 5 years and 56cm length.