Phenotypic plasticity in Barilius vagra (Hamilton, 1822) (Teleostei: Danionidae) from two geographically distinct river basins of Indian Himalaya

Truss-based morphometric analysis was used to examine phenotypic plasticity of Barilius vagra (Hamilton, 1822) inhabiting the tributaries of the Alaknanda (Ganga River basin) and Chenab (Indus River basin), two geographically distinct river basins in the Indian Himalaya. Fourteen landmarks were connected to generate a truss network of 90 parameters on the body of fish. Eighty morphometric traits out of ninety morphometric measurements explained statistically significant difference among six sampling locations of Barilius vagra from streams in the Alaknanda and Chenab basins. Discriminant function analysis revealed 82% of Barilius vagra specimens originally classified into their own groups. 95% of the variance was explained by 13 principal components. Morphometric characters (1–6, 1–13, 2–5, 2–6, 2–14, 3–6, 4–6, 4–14, 6–12, 7–8, 7–9, 10–11, and 13–14) contributed greatly in differentiation of B. vagra populations from different river basins. The Alaknanda basin reflected some mixing within populations, which may be due to common environmental conditions and fish migration in these streams. This study will be helpful in framing site-specific conservation and management strategies, such as net mesh size selection, avoiding overexploitation, stock augmentation and food availability for different fish populations.

Characterization of the complete mitochondrial genome of Barilius malabaricus and its phylogenetic implications

Bariliine fishes are important components of the ornamental as well as subsistence fishery sectors in India. Many of the species in the genus Barilius are threatened by habitat loss and therefore need to be met with conservation initiatives. Effective conservation measures, however, require clarification of species identities and resolution of the validity of many species currently treated as synonymous or sub-species. The complete mitochondrial genome data provide better insight into phylogenetic information than the short fragment or single gene based analysis. Thus, we have sequenced the complete mitochondrial genome of Barilius malabaricus, one of the important fish species in the fresh water ornamental sector, for better understanding its phylogenetic status. The 16,519 bp mitochondrial genome consists of 37 genes which classifies as 22 tRNA, 13 protein coding and 2 ribosomal RNA genes and a control region. Overall, the mitochondrial genome bears the typical gene order and composition as in other fishes. Further, the COI, cytochrome b and 16S rRNA gene sequences revealed that, B. malabaricus is genetically closer to B. canarensis and B. bakeri compared to other Barilius species. Also, the Barilius species of west flowing rivers in Western Ghats were consistently recovered as a clade distinct from other species. We therefore suggest to retain the genus name Barilius for the species from the Western Ghats until a comprehensive analysis based on both morphological and molecular markers reveals the relationship between species now variously placed in the genera Barilius and Opsarius in greater detail.