Insights into the impact of climate change on economic trajectories of North Sea demersal fisheries derived from a spatially explicit bio-economic model

North Sea demersal fisheries are increasingly challenged by a multitude of pressures. Climate change and its socioeconomic consequences as well as the diversification of marine spatial development for offshore energy production, transportation, and conservation are particularly affecting these fisheries, altering the state of target stocks and cutting off access to fishing grounds. To assess the impact of these developments, we applied the spatially explicit bio-economic simulation and optimization model FishRent to simulate the effects of three different climate change scenarios on the profitability of three North Sea demersal fishing fleets from Germany, Norway, and the United Kingdom fishing for cod, saithe, and hake. Our scenarios, which were based on macroeconomic model projections and developed by climate change and fisheries experts, included projections of prices, management strategies, and spatial development. The simulations indicated a continuous increase in profits in a scenario focused on economic development and open markets, while increases in a scenario centered around sustainable development and conservation were less pronounced, albeit steady. A scenario of increased focus on national economies and reduced global trade led to decreasing profits, linked to the overuse of economically crucial North Sea cod stock. Throughout all scenarios, the effects of price developments and management strategies far outweighed effects of marine spatial competition, which were marginal. Spatial dynamics of the fleets showed regional differences, where fuel price increases and insufficient investments in fuel-saving technologies led to the retraction of the UK fleet to less distant fishing grounds, not fully realizing the allocated quota. Our results highlight the intricate socio-economic dynamics in fisheries that are insufficiently covered in most fisheries models and reveal research gaps, particularly the incomplete mechanistic understanding of area closures and stock-recruitment dynamics. Yet, they also illustrate a basic principle of fisheries management, where consistent unsustainable use of a fish stock leads to economic collapse and substantial long-term economic damage for the participating fleets.