This chapter describes the wealth and variety of marine life, the challenges it faces and the scale of human impacts so far. It first talks about the threats to marine biodiversity, including fisheries exploitation, pollution, climate change and ocean acidification, and habitat loss. Then, it provides general principles for conservation of sea. It also sets out a perspective on current conservation and management approaches, and the significant changes needed to these approaches in the future. Although marine conservation science has developed theory, concepts and principles, the empirical understanding and evidence base which managers and policy makers seek remain limited, due to the vast scales and diversity of systems and approaches involved. © 2013 John Wiley & Sons, Ltd.
