Fish Biodiversity and Its Periodic Reduction: A Case Study of River Narmada in Central India

Studies on fish biodiversity are important for planning remedial measures for conservation of our rich aquatic biodiversity resources. The variability in life is largely governed by the environment and genes they possess. Thus more than 99% of all species amounting to over five billion species that ever lived on earth are estimated to be extinct. Information from the available sources suggest that about 1.2 million have been documented and over 86% species are still not yet documented. Besides natural disaster, about 99% species are presently considered as threatened species and are at great risk from human activities, primarily those driving out by habitat loss, introduction of exotic species, global warming, construction of dams, over fishing activities, increasing demand for water, the damming of rivers throughout the world, the dumping and accumulation of various pollutants, and finally invasive species make aquatic ecosystems one of the most threatened part on the planet. Thus it is not surprising that there are many fish species that are endangered in both freshwater and marine habitats.