Abstract: The management of the Baltic fisheries has previously focused on dynamics that are limited in terms of spatial and temporal interactions. Research suggests that the interaction between habitat and trophic interactions combined with environmental influences are required. Using a data driven approach within a Bayesian network model our research has been able to highlight the complex situation in the Baltic Sea. The model is based on the information observed for each of the twenty seven thousand fine scale habitat polygons. This information consists of structural (depth, distance from Baltic sea mouth, rugosity and habitat type), environmental (Spring and Summer temperatures, phosphate and nitrate concentrations, salinity, anoxic levels), trophic (various plankton groups, macrozoobenthos, benthic biomass of flatfish, herring, sprat and cod, pelagic biomass of sprat and herring) and the level of Baltic cod catches. Modeling the non-stationary dynamics through 41 years highlights the role of environmental and trophic changes on Baltic cod biomass. The widely published series of events that led to the demise of the fisheries is supported but the role of sprat as a direct influence on cod is difficult to determine. Critically this modeling approach is able to examine the dynamics at a fine spatial resolution and with an indication of the certainty of the model predictions. The state of cod in each habitat polygon can be determined from a limited suite of Baltic Sea observations. The non-stationary nature of the model highlights that fisheries management needs to account for structural and environmental factors in an evolving trophic system.

Bio: My long-standing research interest in natural systems and conservation initiatives stem from a diverse career in natural resource management spanning government agencies to non-government organisations including commercial companies. Following a zoology degree (University of Melbourne), I completed a masters in landscape ecology  (University of New England) and finally a doctorate in coral reef ecology (University of Queensland). I have developed a special suite of skills that include complexity modelling, empirical statistics, spatial analysis and ecology. Pursuing my aspirations of coral reef ecology initially saw me immersed in data collection and technical preparation activities for the Great Barrier Reef. Fieldwork is my passion! The Doctorate created the space for applying new skills in network modelling. This advanced my scientific capacity until I felt compelled to approach the conservation planning field in a more holistic manner as promoted at the Stockholm Resilience Centre. The postdoctoral fellowship with Dr Bodin provided an excellent basis to appreciate the analytical approaches to social and environmental systems analysis. My subsequent researcher position with Dr Blenckner had a more marine focus, but still retained the core emphasis of socio-ecological analysis. My particular research focus is to ensure the modelling methods selected are able to capture the complexity of the system without diminishing the potential to appreciate the over arching trends