Investigating the drivers of the Nordic Seas food-web dynamics using Chance and Necessity modelling

Marine ecosystems are under pressures of human activities that have altered their dynamics and structure during the last five decades, but there can also vary due to internal dynamics or chance. Managers focus on human activities and often ignore the contribution of internal dynamics and chance to ecosystem dynamics in the decision-making process. In this thesis, I use food-web modelling based on the principles of Chance and Necessity to explore the possible variability of the Nordic Seas’ food-web. I show that internal dynamics and randomness have a key role in the variability of marine food-webs. I also show that climate change and fisheries affect the variability of the Nordic Seas in a combined manner, which suggest that both stressors should not be considered separately for management. I suggest that Chance and Necessity can used a tool to inform adaptive management, ecosystem-based management, and integrated ecosystem assessment.