This revised edition of a popular textbook is written for students, physical oceanographers, engineers, hydrologists, fisheries experts and a number of other professionals who require quantitative expressions of biological oceanographic phenomena. It is designed to lead the reader, step by step, through a progression from the distribution of marine organisms, to discussions on trophic relations, to a final chapter on some practical applications of biological oceanography to fisheries and pollution problems. The book covers subject matter in the pelagic and benthic environments, and is intended to bridge the gap between entirely descriptive oceanography texts and works on the mathematical modelling of marine ecosystems.