Variation in Morphometric Characteristics of Blackhand Paradise Fish (Polynemus melanochir Valenciennes, 1831) in Cai Rang, Can Tho and Long Phu, Soc Trang, Vietnam
DOI:
https://doi.org/10.48048/tis.2025.10304Keywords:
Adaptability, Environment, Mekong Delta, Morphometric ratios, Morphometrics, P. melanochir, Plasticity, Adaptability, Environment, Mekong delta, Morphometric ratios, Morphometrics, Polynemus melanochir, PlasticityAbstract
Polynemus melanochir is valuable in the Mekong Delta, but its morphology and variations remain unclear; therefore, this study was conducted. This study investigated the morphometric and morphometric ratios of P. melanochir at Cai Rang, Can Tho and Long Phu, Soc Trang. P. melanochir is randomly collected monthly at Cai Rang, Can Tho (freshwater) and Long Phu, Soc Trang (brackish water). 10% formalin is used for preservation before transportation to the laboratory for sex differentiation and to determine morphometric parameters and ratios. The variation in these parameters and ratios concerning sex and site was qualified using t-tests, and 2-way ANOVA was used to evaluate the combined effects of sex and site on these parameters at a 5% significance level. These tests were performed using Jamovi v.2.4.11. A total of 308 fish samples were analyzed for differences in traits. The results showed significant standard length, body depth, and head length differences between the 2 sampling sites, likely influenced by environmental factors like temperature, salinity, and pH. However, sex did not significantly affect most traits except for a few morphometric ratios. The interaction of sex and site factors also regulated the variation in the morphological characteristics of this fish. This study also observed morphometric ratios, noting differences across sites and between sexes. The study highlights the phenotypic plasticity of P. melanochir in adapting to different habitats within the Mekong Delta. The findings contribute valuable morphological data on this fish, provide insights into its ecological adaptability in the region, and contribute to species taxonomy, regional variations, and morphological differences influenced by environmental factors.
HIGHLIGHTS
- Environmental factors such as temperature, salinity, and pH likely influenced the differences observed in standard length, body depth, and head length between sampling sites.
- Sex had minimal impact on most morphological traits, though some morphometric ratios varied between sexes.
- Sex and site interacted significantly to shape morphological traits, underscoring the joint effects of biological and environmental factors on phenotypic variation in melanochir.
GRAPHICAL ABSTRACT
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