An introductory textbook to biological oceanography describing the major marine environments and the marine organisms living in pelagic and benthic habitats. Emphasis is placed on biological production and food chains and their geographical variation according to dffferent physical and chemical regimes.The exploitation and conservation of marine resources are considered. There are sections on both fisheries oceanography and benthic habitats such as coral reefs. Many in situ photographs of planktonic organisms have been incorporated together with in situ observations of plankton behaviour. Overall the book presents a combination of descriptive material and theoretical concepts. Numerous questions and worked examples are provided throughout the text guiding the student in obtaining a thorough understanding and practical working experience of ecological concepts.