Intraspecific morphological variations of the vulnerable loach, Lepidocephalichthys annandalei (Cypriniformes: Cobitidae) in inland waterbodies at southwestern Bangladesh

Abstract

Wild fish populations are unceasingly diminishing in the rivers, ox-bow lakes and floodplains in the Southwestern region of Bangladesh. Investigating the population status of vulnerable wild fish species are vital for the management and conservation of that species. This study aimed to identify the intra-specific morphological variation and determine the population status of Lepidocephalichthys annandalei, in two rivers, the Nabaganga River in Jhenaidah (NRJ) and the Bhairab River in Jashore (BRJ) as well as a flood plain, the Dhakuria Beel in Jashore (DBJ) from Southwestern Bangladesh. Significant differences were observed in seven conventional and five truss-based characters in univariate statistics. Conventional and truss-network results from principal component analysis and CVA exhibited that populations were entirely intermixed, creating a compact cluster within intra-population stages. Four principal components explained 51.93% of the variation in conventional morphometric characters and truss-based characters. A UPGMA dendrogram was independently developed based on conventional and truss-based morphometric characters. Among the individuals of NRJ and BRJ populations confirmed the presence of out-group rather than the DBJ based on morphometric (conventional and truss) features. These notable isolations of populations of this species were supposed to be geographic disconnection and abiotic parameters. The evidence ensuing from the present study would be valuable for genetic studies as well as for in situ management.