Patterns of asymetry of Philippine green mussel (Perna viridis) populations from Manila Bay and San Fernando Bay.

Abstract

Symmetry in animals is important as it bears implications as to how the organism carries out aspects of its life and the conditions inherent in the environment. This study aims to determine the patterns of asymmetry in Perna viridis in two coastal environments, Manila Bay and San Fernando Bay. Live mussels obtained from the two sites were assessed for value length (L), width (W), height (H), perimeter (P) and weight (WT). Results show that mussels obtained at Manila Bay expressed fluctuating asymmetry (FA) for all traits except for weight as compared to those in San Fernando Bay. Mussels obtained in San Fernando Bay expressed greater FA for height. Measurement of water quality parameters in the two sites revealed that dissolved oxygen concentration was lower in the Manila Bay site. A low availability of dissolved oxygen is a form stress for aquatic inhabitants; therefore it is possible that developmental stress is greater in the Manila Bay population. Based on the findings on asymmetry, it also follows that the inhabitant mussel population in Manila Bay exhibits a lower level of developmental stability. These findings can contribute to the present literature regarding the usefulness of the analysis of asymmetry expressed by indicator organisms as a biomonitoring tool.