Solar Ultraviolet Radiation and Climate Change Impact on Hill Stream Fishes of Himalayan Region India

Abstract

 Abstract--Ozone depletion is resulting into elevation in solar ultraviolet-B radiation of 290-320 nm. UV-B radiation and global warming pose threat to Himalayan ecosystem and biodiversity. Hill stream fishes, like Barilius and Nemachelius live in transparent surface water thus increases their chances of exposure to UVR still after photobleaching. Retene a natural chemical found in water become phototoxic with UV radiation. In this study, monitoring of solar UV-B was performed and effect of solar and elevated artificial UV-B was studied on fishes at high and low temperature with retene.Growth, mortality, behaviour, lipid peroxidation, glutathione and catalase were performed. Solar UV-B shows seasonal, diurnal, altitudinal, latitudinal and annual variations with highest value in the month of July to September in Himalayan region India. Retene with UV radiation caused lipid peroxidation, decrease glutathione and generate reactive oxygen species. Barilius bendelisis was more sensitive than Nemachelius rupicola and showed higher mortality at high temperature. UV-B radiation and climate change lead to significant threat to Himalayan aquatic ecosystem.