Central Marine Fisheries Research Institute, India
Title: Panmixia and stable population history in the small pelagic fish, Stolephorus indicus (Indian anchovy) from Indian peninsular waters
Sandhya Sukumaran has her expertise in conservation genetics, genotoxicology, molecular ecology and biodiversity. She worked on reef corals of Gulf of Mannar and Palk Bay to understand their ecology, taxonomy and diversity. The effect of genotoxic chemicals on aquatic ecosystem and the role of sex in shaping evolutionary adaptations were studied using matrix population modeling in Artemia. Presently her research is focused on population and conservation genetics of fishes and its relation to climatic fluctuations in the Indian Ocean.
Conservation of intra-specific biodiversity and bio-complexity of marine fishes is very pertinent as this gives resilience to climatic and environmental fluctuations. Anchovies are small pelagic fishes which occupy a key position in the trophic food web of the ocean. They are sensitive to environmental and climatic fluctuations as they respond with population abundances and crashes. In view of their importance, it is essential to understand the intra-specific diversity and genetic stock structure patterns as diversity is the key to sustainability. Hence, a study was carried out to understand genetic stock structure and historic demography of Indian anchovy, Stolephorus indicus from Indian peninsular waters using mitochondrial DNA markers, mitochondrial ATPase and COI sequences. Indian anchovy, Stolephorus indicus was collected from its range of distribution along Indian peninsular waters; Vizag, Tuticorin, Cochin, Goa and Andamans. Mitochondrial ATPase and COI gene regions were amplified and analysed in 90 and 105 individuals respectively. High haplotype diversity was associated with low nucleotide diversity in both sets of sequences. There were 44 haplotypes out of 90 individuals with a haplotype diversity value of 0.82 and nucleotide diversity value of 0.002 when ATPase sequences were analyzed. The sequences of Cytochrome C oxidase revealed 52 haplotypes out of 105 individuals with a haplotype diversity value of 0.651 and nucleotide diversity value of 0.002. Overall genetic differentiation (Fst) was low and insignificant between populations indicating panmixia. Historic demographic analyses showed signals of stable population size. Larvae of S. indicus is pelagic and widespread dispersal of larvae due to ocean currents may be contributing to substantial mixing and consequent homogeneity of stocks across Indian peninsular waters.