Dentex dentex, the Common Dentex, is a species of fish in the Sparids family, commonly called sea breams and porgies. Dentex dentex is common in the Mediterranean Sea, but also seen in the Black Sea and the Eastern Atlantic Ocean. Both the genus and species Latin names Dentex are related to dentēs which means “teeth”.
The genus Dentex belongs to the family Sparidae, superfamily Percoidea, sub-order Percoidei, order Perciformes, class Actinopterygii, phylum Chordata and kingdom Animalia. Besides the Common Dentex, this genus also includes the Large-eye Dentex (Dentex macrophtalmus), the Pink Dentex (Dentex filosus) and the Crowned Dentex (Dentex coronatus), all common in the waters surrounding Malta. The Morocco Dentex (Dentex maroccanus) lives along the coasts of Morocco.
All Dentex are all very fast and good swimming fishes. They are gregarious, forming crowded schools. In the specific, the Dentex dentex moves fast in open seas, in enormous schools, looking for prey, chiefly other fishes, which it seizes with its robust teeth and devours quickly.
The body of the Dentex dentex is compressed on the side and wholly covered by great cycloid scales, with light blue-silver reflexes. The colour is similar in all the various species: the back is dark blue, at times with iridescent dots, the belly and the sides are silvery, whilst a black-blue spot is evident in the zone under the pectoral fins. The dimensions vary from one metre of length for the Dentex dentex, to 50 cm for the Large-eye (Dentex macrophtalmus).
The tip of the head has a clearly visible prominence due to a remarkably developed supra-occipital crest. The eyes, large and protruding, are lateral. The horizontal mouth is quite small compared to the body size. Its jaw is characterised by robust teeth of various shapes; the fore teeth end in a hooked shape, whilst the others are sharp. The essential function is to hold the prey, rather than to chew it.
When the mouth is closed, the front teeth jut out from the lip. On the sides of the body, the lateral line organ is clearly visible. The dorsal fin is uneven and in a quite retracted position. Two regions are visible: the fore one, sustained by 10 to 13 thorny rays and the back one, tender. The pectoral fins are quite broad, whilst the ventral ones are poorly developed. The anal fin, sustained by three thorny rays, is rather short. Dentex dentex are also characterised by a diphycercal (bipartite) tail.
The Common Dentex, like many other congeners, has a “hermaphrodite gonad”. The operation of the gonads is set in a very sophisticated way, by a complex hormonal mechanism. If the balance between the various hormones involved is broken, then we have the phenomenon of the “sexual inversion”.
The mating takes place in summer and during this time the specimens of Dentex dentex (and the same applies for other species), accumulate a remarkable reserve of fat, visible outside, due to the presence of protuberances. The eggs are laid close to the rocky coasts, where the marine vegetation is particularly rich, and stick to them. From the fecundate egg, a larva develops which will then complete its own development in open sea.
The photo of this Common Dentex was taken at a depth of 20m at Reqqa Point on Gozo’s north coast.
Photo taken by Brian Azzopardi
