Knowledge of species’ distributions and the relation to ocean productivity is key in underpinning an ecosystem-based management approach of the marine environment. Marine habitats provide fish and shellfish resources critical for the wellbeing of society, therefore it is critical to understand the factors and processes that have interacted to cause historical changes in the distribution and productivity of living marine resources.
Regarding the quantification of productivity, a generic methodology has been assembled and tested in the North Sea for calculating new (nitrate based) primary production, where total net production was estimated using remote sensing data. Both new production and total net production estimates compare reasonably well in terms of patterns to the results of two coupled hydrodynamic-ecological models in the North Sea.1
Climate change is considered one of the main driving forces behind currently observed shifts in species ranges and changes in productivity. However, many other drivers impact habitats and distribution patterns of fish and shellfish, such as fishing pressure in particular, closed areas or new habitats associated with offshore energy production, eutrophication, artificial introduction of species, as well as changes to marine policy. Interactions between different drivers are likely to complicate future projections.
Changes in the distribution of marine organisms are becoming increasingly documented including shifts towards higher latitudes or deeper waters in response to ocean warming. Within temperate latitudes, these shifts are associated with the appearance of Lusitanian fauna (organisms traditionally distributed in warmer waters) and reduced extent or loss of boreal species. In European waters and elsewhere, these climate-driven shifts as well as the increasing number of alien species introduced via ballast waters or released from aquaculture are creating novel mixtures of species with unforeseen consequences to ecosystem structure and function.
Within VECTORS, bio-economic models were developed which allowed integrating bio-physical and economic aspects of climate change, in order to investigate their combined effects on North Sea flatfish and shrimp fisheries.
VECTORS has developed a variety of modelling tools to help understand changes in species distribution and predict future changes and examine the impacts of multiple stressors and drivers on living marine resources and various economic sectors.234 These investigations included statistical approaches as well as physiology-based models, aiming at a mechanistic understanding of the relevant ecological processes and quantitative estimates of species responses to environmental factors.
A meta-analysis of this variety of modelling approaches has been applied in order to identify hot spots of change in European Seas.