Sustained and predictable biomass yields from the world's oceans are essential to the health of the world economy. The potential impacts of global change on ocean productivity require both scientists and policy makers to seek the causes of change and to determine the types of remediation needed to ensure continued, adequate biomass yields. This interdisciplinary study, containing contributions from experts around the globe, synthesizes a large body of information drawn from multiple sources and provides a cohesive study of the theory and management of large marine ecosystem resources