Genetic and morphological assessment of a vulnerable large catfish, Silonia silondia (Hamilton, 1822), in natural populations from India

In silico analysis of mitochondrial DNA genes: implication for conservation of Tor putitora (Hamilton, 1822)

Tor putitora is an endangered cyprinid fish constrained to cold water and is also considered an indicator of a healthy aquatic ecosystem. The present study aimed to examine the haplotypic diversity, genetic variation and population structure of T. putitora isolates using COI and Cyt b gene sequences submitted in GenBank. Bioinformatic analysis was carried out using 106 COI and 183 Cyt b gene sequences as well as 2 reference genome sequences. Analysis of COI and Cyt b gene reveals 18 and 85 haplotypes respectively. Mutation was observed at 44 different sites in COI and 173 in Cyt b gene sequences. Haplotype 4 and haplotype 37 were considered ancestral in COI and Cyt b respectively. Analysis of COI gene reveals moderate haplotype diversity (0.630) and low Nucleotide diversity (0.00662) whereas Cyt b has higher haplotype diversity (0.804) and low Nucleotide diversity (0.00582). Moreover, the neutrality test such as Tajima's D, and Fu's Fs showed negative values in both gene sequences, suggesting population expansion attributed to habitat destruction. So, comprehending the genetic variability within and among the T. putitora population is crucial for conserving and managing this species. Integration of genetic diversity into conservation planning can enhance the effectiveness of breeding programs and habitat restoration efforts.

Anthropogenic risk assessment of riverine habitat using geospatial modelling tools for conservation and restoration planning: a case study from a tropical river Pranhita, India

The riverine ecosystem provides multiple benefits to human community and contributes to the sustainable development of the ecoregion. The growing dependency on these ecosystems has largely contributed to aggravating the ecological risks, habitat degradation, and loss of ecosystem services. The present study evaluates the ecological risk emanating from nine anthropogenic stressors including river use, hydro-morphology, catchment pollution, and biological stressor on river Pranhita in Godavari Basin of Peninsular India using InVEST (Integrated Valuation of Ecosystem Services and Tradeoffs) Habitat Risk Assessment model. The primary field survey, remote sensing, and secondary data-assisted spatial modelling results revealed low ecological risk (R = 0.65 of 3) in river Pranhita due to anthropogenic activities. Sediment loading, the inflow of nitrogen, and habitat fragmentation were the major stressors with relatively higher risk score (> 1); influence on a sizeable portion of riverine habitat (29-75% of the total area under high-risk zone) indicates the mounting threat from catchment activities. The low-risk value observed in protected river reaches as compared to unprotected areas is likely to be influenced by the abundant presence of intact riparian vegetation which mitigate the catchment stressors and minimal anthropogenic activity within protected areas. This study demonstrates the application of InVEST HRA model for ecological risk assessment of riverine ecosystems and fish assemblages along with their input data generation framework. This has the potential for prioritization of sensitive habitats based on computed ecological risk and stressor identification based on their exposure and consequences for developing appropriate mitigation measures. This model is spatially explicit and accommodates user-defined criteria for ecosystem-level assessment at a regional and national scale to facilitate the resource managers and policymakers for conservation and restoration planning and implementation of targeted management measures for sustainable development.

Phenotypic variation of Chitala chitala (Hamilton, 1822) from Indian rivers using truss network and geometric morphometrics

Chitala chitala (Hamilton, 1822) is an economically important food fish species occurring throughout Indian rivers, which also has ornamental value. This study focuses on morphological variations in C. chitala from seven river basins across India namely; Son, Tons, Ken, Brahmaputra, Ganga, Gomti and Gandak. A truss network was constructed by interconnecting nine landmarks to generate 36 morphometric variables extracted from digital images of specimens sampled from the study locations. Transformed truss measurements were subjected to principal component analysis (PCA), canonical discriminant function analysis (CDFA) and discriminant analyses of principal components (DAPC). DAPC function coefficients performed much better in capturing the variation pattern and discrimination between the rivers which was not achieved using CDFA. Eight truss variables were identified with significant and highest loading for truss variables on principal components and coefficients on discriminant function from DAPC contributing to maximum variation between the rivers. Performance graph and functional distribution of identified truss variables clearly indicated distinction between the rivers. Thin plate spline analysis and procrustes shape analysis further showed the variation in morphology between specimens across the rivers. The significant parameters differentiating specimens from different rivers were linked to dorsal fin origin, the base of the pectoral fin and the perpendicular point on the anal fin from the dorsal fin origin. Variation in the hydrodynamics of the rivers studied might be possibly affecting the fin kinematics and consequently leading to adaption seen as phenotypic variation in C. chitala. The results showcased in the present study shall help in better understanding of intra-specific diversity which is significant for management and conservation of a species.