Fisheries science is the academic discipline of managing and understanding fisheries. It is a multidisciplinary science, which draws on the disciplines of limnology, oceanography, freshwater biology, marine biology, conservation, ecology, population dynamics, economics and management to attempt to provide an integrated picture of fisheries. In some cases new disciplines have emerged, as in the case of bio-economics and fisheries law. “Methods in Fisheries Science & Aquatic Ecology” is a text book targeted for UG (B. Sc, B. F. Sc. Degree courses) and PG (M. Sc, M. F. Sc., Degree and Diploma courses) students studying Ichthyology or Fish and Fisheries (General, Applied) or Fishery Science or Aquatic Ecology as a subject in the traditional or Agricultural Universities of India. The large part, especially the content on fishery and to great extent habitat ecology is suitable for use by the students of marine ecology and fishery science as these methods are common in fresh and marine water, both. In respect of ecology, salinity is an additional factor. The book has two sections A) Field and Laboratory Techniques in Limnology/Aquatic Ecology or Biology/Aquatic Environment/ and B) Techniques in Fishery Biology/Science. Both sections cater to fresh and marine water. The methods described in the book can be directly used for carrying out a practical exercise. New practical exercise(s) can be taken up from the book and included in the syllabus, both at UG and PG level or related Diploma courses. Since the book provides methods on water analysis and fishery science at one place, it is also a suitable reference book for researchers getting introduced to the field of fishery and environmental science, as well.