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 about 30%.
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.
Most of the EU commercial catch is currently taken from stocks that are assessed. There is, however, a clear trend from north to south: almost all catches in the north come from assessed stocks, whereas in the south this only happens for around half of the catch.
Of the assessed commercial stocks in the NE Atlantic, about one third is outside safe biological limits. In the Mediterranean, about half of the assessed stocks are fished outside safe biological limits. In the Black Sea no stocks are assessed.
The overall size and capacity (power and tonnage) of the European fishing fleets continues to follow a downward trend in all countries groups – EU15, EFTA, EU7, and Bulgaria and Romania. There are still however important issues concerning data availability and quality that need to be overcome to allow for a more robust assessment, especially for the Member States who have most recently joined the EU.
The average size of vessels seems to be increasing in EU15 and EFTA, whereas in EU7 and in Bulgaria and Romania there seems to be a downward trend.
The increase in the average size of vessels in the main European fishing fleets, i.e. EU15 and EFTA, possibly indicates a shift towards trawlers and purse seines, which are usually larger than vessels using passive gear and hence exert a greater fishing pressure. Also, other parameters such as technological developments, type of fishing gear and level of activity should be included in the analysis of fleet capacity to more accurately assess the effective fishing capacity of the European fishing fleet.
European aquaculture production has continued to rapidly increase during the past 15 years due to the expansion of marine production. EU 15 and EFTA countries dominate EU’s aquaculture production, where Norway accounted for nearly 40% of the total European production in 2008, followed by Spain, France, Italy and the United Kingdom. Turkey is the most important producer in the EU7 + EU2 + others, having increased its output by nearly 200% from 2001 to 2008.
The major increase in aquaculture production has been in marine salmon culture in northwest Europe and, to a lesser extent, trout culture throughout western Europe and Turkey.
Aquaculture production intensity, as measured per kilometre of coastline length, is two times higher in EU 15 + EFTA countries compared with EU7 + EU2 + other countries. This intensity is likely to continue to rise as marine aquaculture production increases, particularly since the culture of new species, such as cod, halibut and turbot, is becoming more viable. This increase represents a rise in pressure on adjacent water bodies and associated ecosystems, resulting mainly from nutrient release from aquaculture facilities. The precise level of local impact will mainly vary according to species, production techniques and local natural characteristics.