Study of the growth of Trachurus trachurus (Linnaeus, 1758) fished on the eastern coast of the Moroccan Mediterranean

Abstract

Trachurus trachurus (Linnaeus, 1758) is a semipelagic fish common in the waters of the Moroccan Mediterranean and is of major economic importance because it occupies an important place in fish landings. The population of the eastern coast was monitored during the period from October 2017 to September 2018 using monthly sampling. This work focused on the study of the growth biology of this species. In total, 390 specimens were sampled. The total lengths of the individuals collected varied between 7.8 cm and 33.8 cm for a weight that varied from 3.78 g to 310.52 g. The study of the growth of this Carangidae and the estimation of its age are based on the reading of the otoliths. The increase in length follows the linear Von Bertalanffy model; thus, it is rapid for juveniles and decreases with age. Similar growth in length and differential growth in weight were demonstrated between the two sexes. This difference is apparent only from the fourth year onwards and remains in favour of females. The results obtained constitute a valuable contribution to a better understanding of Trachurus trachurus biology and to the implementation of stock assessments to ensure the sustainability of catches of this species.