Biodiversity in oceans and seas
Seas and oceans cover nearly three quarters of the Earth’s surface. Human interference with the natural environment causes changes in their natural condition and biodiversity. The average surface acidity of seas and oceans has been gradually growing for several decades now (since 1990, the pH of oceans has decreased from 8.10 to 8.06). These changes, caused by factors such as increased CO2 emissions, negatively affect organisms which live in seas and oceans, especially those whose skeletons are built of calcium carbonate.
In order to maintain and strengthen natural biodiversity in the world, Key Biodiversity Areas (KBAs) have been established under the auspices of the International Union for Conservation of Nature (IUCN). Some of these areas are protected by local legal regulations. From among all the marine areas in the world considered by international organisations of key importance to biodiversity, 46% are nowadays preserved (compared to 37% in 2005). Legal protection extends to the largest degree to key marine areas in Europe (71%), and to the smallest in Western Asia (16%). Since 2005, this indicator has improved most notably in Northern and Sub-Saharan Africa, where the percentage of the protected key marine areas has grown from 22% and 25%, respectively, to 40%.
In Poland, 175 Key Biodiversity Areas with a total area of 61,000 km2 have been established, 45 of which are marine areas. Nearly 90% of Poland’s key marine areas are protected by the law. This percentage has grown considerably since Poland joined the EU (in 2003, it was 29%) and when some areas were added to the Natura 2000 programme.
Biodiversity of seas and oceans is threatened by e.g. overfishing, meaning excessive and unregulated exploitation of fisheries. This causes the populations of the fished species to fall below levels allowing their safe restoration. For the purpose of monitoring sizes of fish populations, they are classified into three categories: overfished stocks, fully exploited stocks and non-fully exploited stocks. Only the two latter categories are regarded as biologically sustainable, and there have been increasingly fewer of them in the world: the percentage of fish stock at biologically sustainable level has decreased from over 70% in 2004-2006 to the current 66%.
Average proportion of Marine Key Biodiversity Areas (KBAs) covered by protected areas (%)Download more data (.xls)
|Latin America and the Caribbean||31.1||41.5|
Protection of sea areas in Poland
In 1992, during the Earth Summit in Rio de Janeiro, a Convention on Biological Diversity (or the Rio Convention) was drafted and subsequently signed by 196 countries. Following its provisions, the EU established a European Ecological Network Natura 2000, whose aim is to preserve natural habitats and valuable or threatened species. The network is based on two directives: the Birds Directive (on the conservation of wild birds) and the Habitats Directive (on the conservation of natural habitats and of wild fauna and flora). The Natura 2000 network extends over 573,000 km2 of marine areas in the EU, of which 7,000 km2 are situated within the Polish territories.
Coverage of protected areas in relation to marine areas (Exclusive Economic Zones)a (%)
a Exclusive Economic Zone is an area established by international agreements, where the coastal state has the exclusive sovereign right to scientific research, exploitation of natural resources, construction of installations and structures, as well as the protection and preservation of the marine environment.Download more data (.xls)
Polish marine fisheries
The amount of fish and marine organisms fished annually by the Polish fishing fleet has grown from 171,000 tonnes in 2010 to 195,000 tonnes currently. In this period, fishing in the Baltic Sea has intensified, and deep-sea fishing has declined.
Fishermen working on vessels flying the flag of Poland fish mainly in the Baltic Sea. Baltic fisheries yield 74% of the total fish catches in Poland (65% in 2010). Sprat constitute the largest part of all the Polish fish catches in the Baltic Sea (51%). They are followed by herring (28%) and flounder (11%). Cod accounts for only 3% of Poland’s total fish harvest, which is much less than at the beginning of the decade. In 2010, 53% of all fish caught in the Baltic Sea was sprat, herring accounted for 22%, cod for 11%, and flounder for 10%.
The Polish fishing fleet performs deep-sea fisheries in the Pacific and North-Eastern Atlantic, which together yield 26% of Poland’s total marine fish and shellfish catches. Deep-sea fishing has a diversified structure, in which horse mackerel has the largest share (24%), and cod has a considerable share (5%). In 2010, horse mackerel also accounted for the greatest part of the total fish catches (66%) from those areas, and was followed by krill (11%), sardines and gilt sardines (10%), and cod and mackerel (4% each).
The level of the exploitation of the Baltic Sea fisheries has been gradually increasing over the last decade: currently, 75% of fish stocks are overfished, whereas in 2010 it was 60%. In the same period, the level of exploitation of the North-eastern Atlantic (part of which is the Baltic Sea) has considerably fell: now, 38% of its total fish stock is overfished, whereas in 2010 it was 61%. In order to protect its fish stocks, the EU is implementing rules regulating the management of European fishing fleets, which is achieved by the joint adherence to the Common Fisheries Policy. As far as the Baltic Sea macroregion is concerned, a long-term scheme has been devised for the populations of cod, herring and sprat.
Fish and shellfish catches of the Polish fishing fleet (thousand tonnes)Download more data (.xls)