The marine environment of the European Union is characterised by ecological as well as socio-economic forms of change. Introduction of Invasive Alien Species (IAS), through ballast water discharge, deliberate introduction or other vectors, can drastically change the structure and functioning of native ecosystems. But also native species, such as harmful algae or jellyfish, can show sudden outbreaks with severe consequences for the local environment. These outbreaks can be triggered by natural as well as human drivers, such as nutrient discharge. More gradual changes in the marine ecosystem entail, for example, northward shifts of fish stocks driven by climate change. Lastly, changes in the socio-economic sphere, such as market developments and marine policy, can have direct and indirect consequences for marine ecosystems.

These changes to the marine ecosystem are largely driven by socio-economic factors, but they also have considerable socio-economic impacts. Many fisheries experience impacts from marine protected areas, offshore wind energy, as well as ecological changes. For example, the invasive Mnemiopsis leidyi jellyfish, which is abundant in the North Sea, has been shown to severely impact fisheries in the Black Sea. Jellyfish outbreaks can also affect beach tourism. Ecological change can also have consequences for international treaties: the northward shift of North Sea mackerel stocks, and its consequences for North Sea fisheries policy, is a case in point.

VECTORS has investigated the main ecological and socio-economic changes in the marine environment, as well as their most important socio-economic impacts. Bio-economic fisheries models have been developed to investigate the interaction between fishing fleets and the marine ecosystem under different socio-economic and policy scenarios, as well as the economic impacts to the fisheries. Non-market valuation studies have been carried out to estimate the economic impacts of ecological change on coastal tourism. Impacts on international fisheries management have been analysed through game-theoretic analysis. Impacts on the wider economy have been investigated through a general equilibrium model, which describes not only the different sectors in the economy but also linkages between the sectors.