Otolith mass asymmetry in Otolithes ruber (Bloch & Schneider, 1801) (Actinopterygii: Perciformes) collected from the Iraq marine waters

Abstract

Water pollution is mainly an anthropogenic event affecting water resources of all types. With such a happening, fish are harmfully disturbed. Otolith mass asymmetry can reveal some growing disarrays of fish due to environmental impact. Particularly, high level of otolith mass asymmetry can negatively disturb fish life, consequently the assessment of the asymmetry is imperative for each fish species. In the present work, the otolith mass asymmetry was computed as the difference between the mass of the right and left paired otoliths divided by average otolith mass in Otolithes ruber. According to the previous cases obtained on other symmetrical fish species, the absolute value of x in O. ruber does not depend on fish length and otolith growth rate, while the absolute value of otolith mass difference is boosted with the fish length. The value of x was between -0.2 and +0.2.