Abstract
The main purpose of this study, was to identify and describe the presence of the parasite Lernaeolophus sultanus (Milne-Edwards, 1840) in Atlantic horse mackerel fish, Trachurus trachurus (L, 1758) in the western coast of Libya. A total of 108 individuals of T. trachurus fishes were collected during June of 2022. A copepod parasite was isolated from the host, and preserved in 70% alcohol after which examined by a compound microscope. An adult female of the parasite L. sultanus was removed from the buccal cavity of the host. The results of this study was the first time record of L. sultanus in T. trachurus captured from the western coast of Libya.