The aquatic ecosystems such as lakes, ponds, rivers, wetlands, reservoirs, estuaries and oceans along with their disparate flora and fauna form a splendid synthesis of a unique life. They together are instrumental in sustaining the life on earth. Their role in regulating the biosphere cannot be disregarded. The abundance and variety of life in the various aquatic habitats enriches the biodiversity in general and looks after the well being of life residing on land in particular. Water is without doubt the elixir of life but with the inevitable anthropogenic influence, it is undergoing depletion and deterioration. The aquatic biodiversity is very crucial in providing us the food, atmospheric oxygen, running the biogeochemical cycles, redeemer in food shortage and protection against the global climate change. The research articles, reviews and case studies on the plankton, benthos, fish reproductive physiology, seasonal variations, water quality, sediment quality, abiotic parameters presented in these ISCA proceedings 2019 focuses on the qualitative and quantitative maintenance of not only the aquatic ecosystems but also the indispensable animal and plant life residing in it. Conserving and maintaining our aquatic ecosystems will go a long way in not only providing us the food, clean water, jobs, economy and tourism enhancement but also save us from climate change, floods, earthquakes and other cataclysms. The collection of edited papers in this book will be of immense value to the young researchers in particular and academicians, science enthusiasts and student community in general.