Asymmetry in some morphological characters of Siganus rivulatus collected from beach of Jalyanah-Benghazi coast: possible use of asymmetry in fish as an indicator of marine pollution.

Abstract

Fluctuating asymmetry, commonly used as an indicator of environmental pollution, was estimated in eye lens diameter, pectoral fin, pelivical fin and gill arch length of Siganus rivulatus collected from Jalyanah beach. Mean length, weight and condition factor of 15.76 ± 1.72 cm, 50.33 ± 13.05 g and 1.05 ± 0.18 were correspondingly record. The eye lens diameter (t = - 0.01), pectoral fin (t = - 0.05), pelivical fin (t = - 0.06) and gill arch length (t = - 0.05) from both sides were not significantly different. The pectoral fins recorded (0.005 ± 0.022) higher occurrence of fluctuating asymmetry compared with the eye lens diameter (0.002 ± 0.1173, pelivical fins (0.004 ± 0.01578) and gill arch length (0.001 ± 0.02445). Changeable degrees of fluctuating asymmetry were practical in response to ecological stress and could be a useful use as a marker to environmental stress in marine ecosystems.