Evaluating Morphological Asymmetry in Three Species of the Genus <i>Hydrocynus</i> from the White Nile in Sudan

Abstract

The present study aimed to determine and evaluate the level of fluctuating asymmetry (FA) of morphological characters for three species of Hydrocynus from the White Nile. In H. vittatus 41% of morphological characters fluctuated to the right side and 59% to left side. In H. brevis 50% fluctuated to right and 50% to left side, while in H. forskalii 34% fluctuated to right and 66% fluctuated to left side. More scales were recorded along the lateral line on the right side of H. vittatus and H. brevis compared to H. forskalii , while more gill rakers were recorded on the left side of H. vittatus . The smallest asymmetry index was found for PVFL of the three species and the largest index was found for POL of H. brevis . Mean asymmetry index was (3.5%) in H. forskalii , (5.1%) and (4.9%) in H. vittatus and H. brevis , respectively. Absolute asymmetry values were significantly correlated with character size for the number of lateral line scales, head length, pectoral fin length and ventral fin length (P>0.05) and highly correlated for snout length and caudal peduncle length (P>0.001) in the three species. Correlations between means of bilateral characters and body size were significant (P>0.05) for the head length, pelvic fin length and pectoral spine length of the three species. This study is the first of its kind in species of the Nile fish. The present result can be a base line for further study of fluctuating asymmetry in fish and as indicators to detect the level of pollutants in the Nile and the condition of the environment and the organisms.