Paper Title
Contribution to the Study of the Biology of a Coastal Fish, The Saurel Trachurus Trachurus (Linnaeus, 1758)

Abstract
Sampling was carried out at a fishmonger's a (Sidi El Houari, Oran) during the month of January 2020, at random in order to obtain all size classes, a total of 250 specimens were brought back. We selected in this study 31 metric parameters and 8 numerical parameters. The different measured parts of the body are expressed as a function of the total length (LT) or the cephalic length (LC) by the method of least rectangles (reduced major axis) which is a regression equation recommended by TEISSIER (1948). The statistical comparison of numerical characters between the two sexes (females and males) shows no sexual dimorphism, our fish has 22 vertebrae, 74 ± 5 scales on the lateral line, 9 spines on the first dorsal, 33 ± 2 rays on the second dorsal, two spines and 30 rays, 40 ± 3 lower and 15 upper gillspines. The height and thickness of the body greater in females than males which it explains the distance of the pelvic fin from the pectoral fin and the first dorsal fin which is more tongue than the first dorsal fin of the male, the caudal fin and the maxilla also as well as the eyes is more distant to one another. The detected dimorphism extends to the mode of development of the parameters, some metric parameters do not develop in the same way in both sexes. With regard to the height-weight relationship, the parameters of the relationship show for both sexes a majoring allometric growth where b is less than 3, the weight increasing proportionally and slightly more slowly than the length. Keywords - Fishmongery, Numerical parameters, Dimorphism, Fin, Vertebrates.