Intraspecific Shape Analysis of Bali Sardinella (Sardinella lemuru) Using Geometric Morphometrics Collected in the Coast of Cabadbaran, Agusan Del Norte, Philippines

Abstract

Modern techniques are often applied to analyze the body shape differences among biological organisms. Also, taxonomy and systematics are two essential fields of Biology concerning shape discrimination. This study aims to identify the shape variations of Sardinella lemuru (Bali sardinella) using Symmetry Asymmetry Geometric Data (SAGE) Software Application. A total of 70 fish samples consisting of 35 males and 35 females were collected in Barangay Caasinan, Cabadbaran, Agusan Del Norte, Philippines. Standard laboratory procedures were done and fish samples were subjected to the analysis. Procrustes ANOVA revealed a highly significant difference (P<0.0001) among the components analyzed (individuals, sides, and individuals vs. sides). This implied that each of the fish samples exhibited different body shapes. Principal Component Analysis (PCA) obtained a high rate of Interaction/Fluctuating Asymmetry (76.79%) in males when compared to female samples (74.08%). The shape dissimilarities within the populations were associated with genetic components, ecological adaptations-swimming, predator escape, and resource competition. Thus, the present study identified shape disparity within the fish populations. The development of employing modern techniques enhances scientific methods to quantify shape dissimilarities among species individuals and assemblages.