Morphological asymmetry in two marine fish species Acanthopagrus arabicus (Family: Sparidae) and Planiliza klunzingeri (Family: Mugilidae), collected from brackish and freshwater environments in southern Iraq

Abstract Morphological asymmetry was analysed in two marine fish species Acanthopagrus arabicus and Planiliza klunzingeri, in brackish and freshwater habitats in southern Iraq. For both species, specimens from the Shatt al-Arab River and Shatt al-Basrah Canal exhibited greater asymmetry values for snout length. In both locations examined, the levels of asymmetry of the physical traits increased as the fish grew. The high levels of asymmetry in the two fish species may be linked to heavy metal pollutants in the two aquatic environments studied.