Invading European Seas: assessing pathways of introduction of marine aliens

Assessing pathways of introduction of marine alien species is essential to identify management options and evaluate management decisions to regulate and prevent new introductions. By critically reviewing related information in scientific/grey literature and online resources, 1369 alien marine species in European seas were identified, of which 1257 were linked to the most probable pathway(s)/vector(s) of introduction. Based on their reported year of introduction, trends in the numbers of introduced species per pathway/vector were assessed on a decadal basis and invasion patterns were described for each pathway. The trend of new introductions of alien species in Europe has been increasing, with more than half of the species probably being introduced by shipping. Marine and inland corridors (primarily because of the Suez Canal) were the second most common pathway of introduction followed by aquaculture and aquarium trade. Aquaculture was the only pathway for which there was a marked decrease in new introductions during the last decade, presumably due to compulsory measures implemented at a national or European level. Introductions via all the other pathways have been increasing, aquarium trade being the pathway with the most striking observed increase. Many more species are expected to invade the Mediterranean Sea through the Suez Canal, as it has been continuously enlarged and the barriers for the invasion of Red Sea species have been substantially decreased. In addition to the existing regulations on aquaculture, the implementation of appropriate management measures on shipping and aquarium trade, e.g. the implementation of the Ballast Water Management Convention, awareness raising among aquarium hobbyists, and also implementation of a stricter legislative framework on the import of non-native aquarium species, could reverse the increasing trend in new introductions.JRC.H.1-Water Resource

Assessing pathways of introduction of marine aliens in European Seas: temporal and spatial patterns

Identification and assessment of the pathways of introduction of alien species is essential for identifying management options to regulate invasions and prevent new introductions, and communicating related risks and costs to policy makers and high administration. By critically reviewing scientific/grey literature and online resources, 1360 alien marine species in European seas were identified, of which 1269 were linked to the most probable pathway(s)/vector(s) of primary introduction. Based on their reported year of introduction, trends in the numbers of introduced species per pathway/vector were assessed on a decadal basis and invasion patterns were described for each pathway. The overall trend of new introductions of alien species in Europe has been increasing (see Figure), with more than half (51.9%) of the species probably being introduced by shipping. The current rate of ship-mediated alien introductions in European Seas is one new species every ~three weeks. Marine and inland corridors (primarily because of the Suez Canal) were the second most common pathway of introduction (37.6% of species) followed by aquaculture (14.8%) and aquarium trade (3.9%). Species introduced by shipping or aquarium trade initially get established in one or more locations, usually in hotspot areas such as ports or metropolitan areas, and then they extend their range by natural dispersal and other vectors, without following a predicted common path. The most common invasion pattern of Lessepsian immigrants is to first get established in the southern Levantine basin, close to the Suez Canal, and then gradually spread to the rest of the eastern Mediterranean basin initially following an anticlockwise direction, and then northwards in the Aegean and westwards towards the Ionian Sea, further westwards along the Italian coastlines and western Mediterranean and also southwards to the North African countries. A frequent pattern of aquaculture-mediated invasions is that more than one sites of introduction (often temporally distinct) exists. These sites are colonized independently and self-sustaining populations are established, gradually expanding by natural processes. Aquaculture was the only pathway for which there was a marked decrease in new introductions during the last decade, presumably due to legally binding measures implemented at a national or European level. Many more species are expected to invade the Mediterranean Sea through the Suez Canal, as it has been continuously enlarged and the barriers for the invasion of Red Sea species have been substantially decreased. Similarly, increased transport through inland navigational European canals will assist more and more Ponto-Caspian species to extend their range into the Baltic and along the European Atlantic coasts. The increasing trends in worldwide shipping as well as within Europe will lead to an increasing trend in shipping-mediated new introductions. For many of these pathways, practical preventive measures are obtainable and there should be no delay in their application, e.g. the implementation of the Ballast Water Convention, more awareness raising among aquarium hobbyists and also implementation of a stricter legislative framework on the import of non-native aquarium species.JRC.H.1-Water Resource

Report of the Workshop on Marine Strategy Framework Directive1 - Descriptor 3+ (WKMSFD1 D3), 4-8 July 2011 ICES Headquarters, Denmark. ICES CM 2011/ACOM:58

This is a short report of the first workshop in a process leading to a technical/scientific ICES report aiming to support EU Member States (MS) in the implementation of the Marine Strategy Framework Directive (MSFD). The process will focus on Descriptor 3 (D3), commercially exploited fish and shellfish, but fisheries-related information relevant for the other Descriptors will also be identified and reported on. The work is led by a small Core Group of experts and, outputs of this and a second workshop involving regional case studies undertaken by the Core Group, will be used in pre-paring a final report. The final report will describe the process, assessment method-ologies and the key issues and decisions, as well as their implications for defining GES and environmental targets and indicators for D3.JRC.G.4-Maritime affair