Connectivity in grey reef sharks (Carcharhinus amblyrhynchos) determined using empirical and simulated genetic data

Grey reef sharks (Carcharhinus amblyrhynchos) can be one of the numerically dominant high order predators on pristine coral reefs, yet their numbers have declined even in the highly regulated Australian Great Barrier Reef (GBR) Marine Park. Knowledge of both large scale and fine scale genetic connectivity of grey reef sharks is essential for their effective management, but no genetic data are yet available. We investigated grey reef shark genetic structure in the GBR across a 1200km latitudinal gradient, comparing empirical data with models simulating different levels of migration. The empirical data did not reveal any genetic structuring along the entire latitudinal gradient sampled, suggesting regular widespread dispersal and gene flow of the species throughout most of the GBR. Our simulated datasets indicate that even with substantial migrations (up to 25% of individuals migrating between neighboring reefs) both large scale genetic structure and genotypic spatial autocorrelation at the reef scale were maintained. We suggest that present migration rates therefore exceed this level. These findings have important implications regarding the effectiveness of networks of spatially discontinuous Marine Protected Areas to protect reef sharks

Water quality under the changing climatic condition: a review of the Indian scenario

The current work reviews the state of Indian water quality under the climate change regime. Rising temperatures will lead to higher concentration of pollutants like nutrients (nitrates, phosphates etc.), persistent organic pollutants and pesticides. Probable negative consequences include increase in harmful algal blooms, toxicity hazards in people etc. Rising temperatures could lead to release of higher amounts of fluoride and uranium due to prevalence of drier oxic conditions, and also arsenic due to release from iron (hydr)oxides. Implications on emerging contaminants, a new class of pollutants without any regulatory status, is not clearly understood. Prevalence of microbes in water is also predicted to increase. Coastal aquifers appear to be at risk from salt water intrusion. Conflicts on the international and national platform is predicted to rise due to issues with sharing of water. Lastly, we also discuss the sustainability options for water in India under a changing climatic regime, under three broad subcategories signifying the roles of (1) science, (2) policies and legal framework and the (3) people perspective, while also highlighting the existing lacunae.by Nilotpal Das, Chandan Mahanta and Manish Kuma