The main pathways for marine non-indigenous species (NIS) introduction in Europe´s seas are shipping (51%) and the Suez Canal (37%). These are followed by aquaculture related activities (17%) and, to a much lesser extent, aquarium trade (3%) and inland canals (2%). This is a pattern observed in all regional seas, except for the Eastern Mediterranean where introductions via the Suez Canal exceed those by shipping.
Trends in pathways show an increasing rate of introductions by shipping and corridors (in particular the Suez canal) since the 1990s, while aquaculture mediated introductions have been decreasing since the 2000s. This can be attributed to the adoption of effective EU regulation. Aquarium trade emerges as a lower but increasing pathway since the 2000s.
Available data shows that the seas around Europe currently harbor 1 416 non-indigenous species (NIS), almost 81% (1 143) of which have been introduced after 1950. These consist mostly of invertebrates (approx. 63%).
The rate of new introductions of NIS is continually increasing with 323 new species recorded since 2000 at pan-European level.
An increase in NIS introductions is observed for all regional seas. The most affected seas are in the Mediterranean, in particular in the Aegean-Levantine Sea. In this region over 160 new species have been recorded from 2000 to 2010.
Marine aquaculture production is increasing in Europe, mostly due to salmon production in Norway. Other types of production are relatively stable since the early 2000s. All aquaculture production in the EU-28 has been equally stable.
In 2012, by far the most cultivated species in Europe was Atlantic salmon, followed by mussels, rainbow trout, European sea bass, gilthead sea bream, oysters and carps, barbels and other cyprinids.
Finfish production accounts for the increase in European aquaculture, while shellfish production has been slowly decreasing since 1999. Aquatic plants production has been emerging since 2007.
The EU fishing fleet displays strong regional differences in terms of its composition, but it is mostly made up of small vessels (59%). There has been a marked decrease in fishing fleet capacity (i.e. number of vessels) between 2004 and 2001 , during which time small vessels decreased at an annual rate of approximately 1% and large vessels at 7% .
Most of the EU fishing effort is deployed by large vessels (74%) with mobile gears, of which the majority (61%) disturbs the seafloor. The decrease in capacity has been followed by a decrease in the effort of large vessels only (over 7% between 2004-2011), while the effort of small vessels has increased by approximately 5%. This is reflected in an overall shift towards gear with less impact on the seafloor.
The observed change of EU fishing effort and the shift towards gear with less impact is indicative of an overall decrease in fishing pressure and impact in European seas between 2004 and 2011.
Approximately 60% of commercial fish landings comes from stocks that are assessed with Good Environmental Status (GES) information. Strong regional differences exist, where the Mediterranean and Black seas remain poorly assessed.
Around 58% of the assessed commercial stocks are not in GES. Only 12% are in GES for both the level of fishing mortality and reproductive capacity. These percentages also vary considerably between regional seas.
The use of commercial fish and shellfish stocks in Europe, therefore, remains largely unsustainable. Nevertheless, important signs of improvement for certain stocks are being recorded in the North-East Atlantic Ocean and Baltic Sea.
Between 1985 and 2012, 7% of all stations in European seas that reported to the EEA showed decreasing trends in summer chlorophyll concentrations, whereas in 4% of the stations, increasing trends were found. In the majority of the stations (89%), no trends were observed.
Based on available data, chlorophyll concentrations, which are an indicator of eutrophication, are decreasing in the Greater North Sea, Bay of Biscay and Adriatic Sea, but increasing in many parts of the Baltic Sea. No trend assessment was possible for the Black Sea.
Between 1985 and 2012, m ost stations in European Seas that reported to the EEA showed no change in trends of concentrations of Dissolved Inorganic Nitrogen (DIN) or orthophosphate. In addition, a decrease in concentrations was observed for 14% and 13% respectively, while only a minority of stations showed an increase.
These trends mostly refer to stations in the northeast Atlantic Ocean and Baltic Sea, however, due to lack of reported data for other regional seas. A vailable data shows nitrogen and phosphorus concentrations are decreasing in the southern North Sea which is an area with a recognised eutrophication problem. In the Baltic Sea, also affected by eutrophication, nitrogen concentrations are decreasing but phosphate concentrations show an increase at some stations.
In 2012, the concentrations of the eight assessed hazardous substances were generally: Low or Moderate for Hexachlorobenzene (HCB) and lindane; Moderate for cadmium, mercury, lead, dichlorodiphenyltrichloroethane (DDT) and 6-Benzylaminopurine BAP; and Moderate or High for polychlorinated biphenyl (PCB).
A general downward trend was found between 2003 and 2012 in the North-East Atlantic for cadmium, lead, lindane, PCB, DDT and BAP, and also in the Baltic Sea for lindane and PCB. No trends could be calculated for the other regional seas.
The extent and volume of the Arctic Sea ice has declined rapidly since global data became available in 1980, especially in summer. Record low sea ice cover in September 2007, 2011 and 2012 was roughly half the size of the normal minimum extent in the 1980s. September ice cover has somewhat recovered in 2013 and 2014 but it was still well below the average for 1981-2010.
Over the period 1979–2014, the Arctic has lost on average 42 000 km 2 of sea ice per year in winter and 91 000 km 2 per year at the end of summer. The decline in summer sea ice appears to have accelerated since 1999.
The maximum sea ice extent in the Baltic Sea has been decreasing most of the time since about 1800. The decrease appears to have accelerated since the 1980s but the large interannual variability prohibits a clear assessment as to whether this increase is statistically significant.
Arctic Sea ice is projected to continue to shrink and thin all year round. For high greenhouse gas emissions, a nearly ice-free Arctic Ocean in September is likely before mid-century. There will still be substantial ice in winter.
Baltic Sea ice, in particular the extent of the maximal cover, is projected to continue to shrink.
Global mean sea level (GMSL) has risen by 19 cm from 1901 to 2013 at an average rate of 1.7 mm/year. There has been significant decadal variation of the rate of increase but an acceleration is detectable over this period. The rate of sea level rise over the last two decades, when satellite measurements have been available, is higher at 3.2 mm/year.
Most coastal regions in Europe have experienced an increase in absolute sea level as well as in sea level relative to land, but there is significant regional variation.
Extreme high coastal water levels have increased at many locations around the European coastline. This increase appears to be predominantly due to increases in mean local sea level at most locations rather than to changes in storm activity.
GMSL rise during the 21st century will very likely occur at a higher rate than during 1971–2010. Process-based models project a rise in 2081–2100, compared to 1986–2005, that is likely to be in the range 0.26–0.54 m for a low emissions scenario (RCP2.6) and 0.45–0.81 m for a high emissions scenario (RCP8.5). Projections of GMSL rise from semi-empirical models are up to twice as large as from process-based models, but there is low confidence in their projections.
Available process-based models indicate GMSL rise by 2300 to be less than 1 m for greenhouse gas concentrations that peak and decline and do not exceed 500 ppm CO2-equivalent but 1 m to more than 3 m for concentrations above 700 ppm CO2-equivalent. However, these models are likely to systematically underestimate the sea level contribution from Antarctica. The multi-millennial sea level commitment is estimated at 1–3 m GMSL rise per degree of warming.
The rise in sea level relative to land at European coasts is projected to be similar to the global average, with the exception of the northern Baltic Sea and the northern Atlantic coast, which are experiencing considerable land rise as a consequence of post-glacial rebound.
Projected increases in extreme high coastal water levels in Europe will likely be dominated by increases in local relative mean sea level, with changes in the meteorologically-driven surge component being less important at most locations.
The warming of the World Ocean accounts for approximately 93 % of the warming of the Earth system during the last six decades. Warming of the upper (0–700 m) ocean accounted for about 64% of the total heat uptake.
An increasing trend in the heat content in the uppermost 700 m depth of the World Ocean is evident over the last six decades. Recent observations show substantial warming also of the deeper ocean (between 700 m and 2 000 m depth and below 3000 m depth).
Further warming of the oceans is expected with projected climate change. The amount of warming is strongly dependent on the emissions scenario.
Surface-ocean pH has declined from 8.2 to below 8.1 over the industrial era due to the growth of atmospheric CO 2 concentrations. This decline corresponds to an increase in oceanic acidity of 26%.
Observed reductions in surface-water pH are nearly identical across the global ocean and throughout Europe’s seas.
Ocean acidification in recent decades is occurring a hundred times faster than during past natural events over the last 55 million years.
Ocean acidification already reaches into the deep ocean, particularly in the high latitudes.
Models consistently project further ocean acidification worldwide. Surface ocean pH is projected to decrease to values between 8.05 and 7.75 by the end of 21 st century depending on future CO 2 emission levels. The largest projected decline represents more than a doubling in acidity.
Ocean acidification may affect many marine organisms within the next 20 years and could alter marine ecosystems and fisheries.
Sea surface temperature in European seas has been increasing in the past century at a faster rate than the global ocean.
The rate of increase in sea surface temperature in all European seas during the past 25 years is the largest ever measured in any 25-year period. It has been several times faster than the average rate of increase during the past century, and it is also much faster than the global ocean.
Globally averaged sea surface temperature is projected to continue to increase although more slowly than atmospheric temperature.
Increases in regional sea temperatures have triggered a major northward expansion of warmer-water plankton in the North-east Atlantic and a northward retreat of colder-water plankton. This northerly movement is about 10 ° latitude (1 100 km) over the past 40 years, and it seems to have accelerated since 2000.
Sub-tropical species are occurring with increasing frequency in European waters, and sub-Arctic species are receding northwards.
Further changes in the distribution of marine species are expected, with projected further climate change, but quantitative projections are not available.
The quality of water at designated bathing waters in Europe (coastal and inland) has improved significantly since 1990.
Compliance with mandatory values in EU coastal bathing waters increased from just below 80 % in 1990 to 93.1 % in 2011. Compliance with guide values likewise rose from over 68 % to 80.1 % in 2011.
Compliance with mandatory values in EU inland bathing waters increased from over 52 % in 1990 to 89.9 % in 2011. Similarly, the rate of compliance with guide values moved from over 36 % in 1990 to 70.4 % in 2011.
Temperature increases in the ocean have caused many marine organisms in European seas to appear earlier in their seasonal cycles than in the past. For example, some species have moved forward in their seasonal cycle by 4-6 weeks. Changes in the timing of seasonal cycles have important consequences for the way organisms within an ecosystem interact and ultimately for the structure of marine food-webs at all trophic levels. The consequences include: - increased vulnerability of North Sea cod stocks to over-fishing; - decline in seabird populations. Marine species may be able to adapt genetically to changed conditions. However, with the current pace of climate warming this may be hampered because genetic changes require several reproductive cycles to occur.