As consequence of the large amount of uses and activities in the coastal zone and the resulting pressures and pollution of the coastal seas, the European Environmental Agency conclude in their report ‘State of Europe’s seas’ from 2017 that Europe's seas cannot be considered to be in a healthy state. Several major messages are (1):

• For species results show that 27% of marine species assessments were considered to be in 'unfavourable conservation status'. The observed loss of biodiversity affects ecosystem functioning and may cause irreversible loss of ecosystem resilience.
• There is a great diversity of seabed habitats across the different regional seas of Europe, with over 1 000 different seabed habitat types identified. 66% of the biogeographic assessments showed 'unfavourable conservation status'.
• Over 650 marine fish species are thought to inhabit European seas. Most of the assessed commercial fish stocks (58%) are not in 'good environmental status' (GES), while 40% of EU catches remain unassessed.
• There are over 180 species of marine birds found throughout Europe's seas, and many of these undertake yearly migrations between feeding and breeding grounds. We can tentatively conclude that approximately one third of marine bird populations are declining, one third are stable, and one third are growing.
• Almost 40% of the world's known marine mammal species can be found in Europe's regional seas. In some regions, marine mammal populations are in unfavourable conservation status.
• Food webs are one of the main regulators of ecosystem dynamics. They play a role in the way ecosystems respond to natural and human-induced changes. Slight changes in food webs can lead to dramatic changes in an ecosystem. These dramatic changes are called 'ecological regime shifts'. Ecological regime shifts in marine ecosystems have been observed in a number of Europe's regional seas.

An unsustainable use of our coasts and seas threatens the services these ecosystems provide to humans and, human activities that depend on the sea directly suffer from damaged ecosystems. In this respect we have to take into account that seas additionally have a large intrinsic value. For example, they provide a free horizon, enable recreation or to experience wildlife. Therefore, adequate planning and management are needed to ensure the health of the seas and to maximise the sustainable socio‑economic benefits they provide (2).

Beside the multiple pressures resulting from direct human activities, climate change is another major threat for the function and structure of coastal systems. Increasing sea level (1,7 mm/year) changes the shape of coastlines, contributes to coastal erosion and leads to flooding and more underground salt-water intrusion (2). Increasing water temperatures will have strong effects on ecosystems and decrease biodiversity.

In twelve brief lessons, the “Ocean Atlas 2017” provides interesting additional facts about the utilization and threats of the oceans (3).