The red king crab (Paralithodes camtschaticus) is a highly valuable resource that also represents a potential threat since it is an alien invasive species in the Barents Sea ecosystem. This thesis explores the use of different interdisciplinary frameworks to analyse how ecological, social and economic concerns could be accounted for in deciding on how the king crab should be managed in the Norwegian part of the Barents Sea. Clarification of terminology used in invasion biology and systematisation of ecological information in order to establish the ecological knowledge base for management forms the basis for further analysis. Bio-economic modelling and discourse analysis are used to explore how uncertainty and the range of services the ecosystem provides can be incorporated in management. Finally the use of ecosystem service frameworks to integrate ecosystem and social science research in ecosystem based management is discussed. The ecological review revealed numerous knowledge gaps in our understanding of how the king crab interacts with native biota. It also identified negative impacts on benthic ecosystems that provide supporting services, and on provisioning services through predation on eggs of commercial fish. Bio-economic analysis illustrated the need to identify the correct relationship between crab stock size and ecosystem damage. It also showed that optimal harvest of king crab cannot be reconciled with the Barents Sea management goal of securing the ecosystem structure. The discourse analysis showed that people recognise both positive and negative impacts of the crab on supporting, provisioning and cultural services. In addition the impacts on ecosystem services we do not have the knowledge to value today, or option values, were important in forming people’s perception on how the crab should be managed. This thesis demonstrates that while the natural sciences have a clear role to play in establishing the ecological knowledge base, uncertainty and the need to account for stakeholder concerns calls for integration of social science research in the management process. Ecosystem service frameworks can be useful tools for identification, integration and evaluation of such information
