Geometric morphometric analysis on the shell of green mussel (Perna viridis) from two culturing sites in Cavite province

Abstract

Green mussel (Perna viridis), locally known as „tahong‟, has been a valuable source of food and livelihood in the country. However, environmental stress is also continually paving its way in posing a threat to the marine environment especially in most culturing sites of green mussel. Morphological plasticity could be used as an indicator of the changes in the marine environment. Thus, the study determined morphological variations on green mussel‟s shell using geometric morphometric analysis and their possible relationship to the physicochemical parameters from two culturing sites in Cavite Province. The geometric morphometric analysis was used to statistically analyze shape variation within and among samples based on their digitized landmarks and the Procrustes superimposition to remove size difference. In addition, the physicochemical parameters such as temperature, pH, salinity, and turbidity were determined. Results showed that the dimension of the shell in terms of shape was relatively similar to both sites. Also, the physicochemical parameters from both culturing sites were relatively similar. Moreover, the Principal Component Analysis, Canonical Variate Analysis, and Discriminant Analysis showed that there was no morphological variation and no significant difference in the digitized landmarks on the green mussel shells from both collecting sites in one collection (p<0.0001). Furthermore, there was no relationship between the geometric morphometrics of P. viridis and the physicochemical parameters from the two culturing sites. This implies that the shell morphology of green mussels in terms of shape might have a high tolerance to the different parameters in the marine environment.