Morphological discrimination of populations of the sword shrimp, Mierspenaeopsis hardwickii, along Peninsular Malaysian waters by traditional and truss-network approaches

Abstract

Traditional morphometric approaches have long been used to describe organisms and detect shape variations both within and among groups. However, advanced techniques such as truss-network systems offer better visualisation of shape variation. The data obtained from these approaches are essential for comprehensive stock assessments and play a significant role in developing effective fisheries management strategies. This study compares the efficiency of two morphometric methods (traditional vs. truss-network) in detecting morphological differences between populations of the commercially important sword shrimp, Mierspenaeopsis hardwickii (Miers, 1878) in the coastal waters of Peninsular Malaysia. A total of 88 M. hardwickii individuals from seven localities in the South China Sea and the Strait of Malacca were analysed using both approaches. Additionally, a discriminant analysis (DA) using Canonical Variate Analysis (CVA) was conducted to classify each population correctly, and an exploratory Principal Component Analysis (PCA) was conducted to quantify and visualise population differences. The results showed that truss-network morphometrics outperformed traditional methods in discriminating among M. hardwickii populations. The scatterplots of the first two PC scores, and wireframe analysis demonstrated significant shape differences, suggesting that the populations constitute specific-stock units for fisheries management. This finding implies ecological or life-history adaptations among M. hardwickii populations. Incorporating truss-network morphometric data into M. hardwickii stock assessments could contribute to a better understanding of population structure and dynamics to support sustainable fisheries management.