LevelPressureEnvironment

NIS2_1

Descriptive

Unknown_NotAssessed

1982-2012

A total of 47 non indigenous species (NIS) belonging to 8 main taxonomic groups (algae and phanerogams; cnidarians; polychaetes; bryozoans; molluscs; decapod crustaceans and stomatopods; ascidians; fishes) are recorded in the assessment area; 24 of these NIS (51%) are considered to be invasive according to the definition of IAS in the TG2 report of the Marine Strategy. The cumulative number of NIS shows a gradual and relatively slow increasing trend until the decade 1972-1982, then it grows faster. Spatio-temporal distribution of the recorded NIS are available in GIS maps. Spatio-temporal distribution of Arcuatula senhousia, Ruditapes philippinarum, Dispanopeus sayi, Rithropanopeus harrisii in the source of pressure area of Po Delta is the following: R. philippinarum has an increasing trend in abundance (northern Adriatic areas have become the second clam production area in the world). A. senhousia had an impressive increase in abundance from mid 90 to the beginning of 2000, after which populations stabilized. D sayi has become one of the commonest crabs in the Po Delta area. As far as the taxonomic group of bryozoa is concerned the ratio between non-indigenous and indigenous species in the Lagoon of Venice is low, however the presence of Tricellaria inopinata is overwhelmingly abundant in comparison to the other species. In the same area Rapana venosa is present with low abundance (5 ind. 10-4 m2 on sandy bottom, 34 ind 10-2 m2 on rocky bottom) and no impact has been detected so far. In the case of the toxic benthic dinoflagellate Ostreopsis ovata, the species was not recorded in the Adriatic until 2002 but surveys of microphytobenthos were rare before that date. Presently, the species is widely distributed along the rocky shores all across the Adriatic Sea, while it is not found in Veneto and Emilia Romagna. Since the first records in Apulia, Marche and Venezia Giulia the abundance of the species has been high up to 10e5-10e6 cells/g macroalga, with maxima generally in late September-October. Over the last ten years no clear trend has been reported in terms of expansion or increased abundance. The isopod NIS Paracerceis sculpta has been recorded since 1981 in the Venice lagoon, while a more recent record (2004) is from the touristic harbour of Ravenna.

Moderate

Activity1: In this area aquaculture is considered a propagation vector for 43% of NIS. The introduction of NIS through aquaculture is mainly due to unintentional introductions caused by movements and transfer of seeds and commercial products of shellfish, Ruditapes philippinarum and Crassostrea gigas are the only species introduced intentionally in this area. Implementation of Reg (CE) 708/2007 is aimed at preventing impacts of NIS voluntary introduced for aquaculture. The propagation of Rapana venosa egg masses take place through marine farming, as associated organism during restocking of aquaculture production. Also in the case of Ostreopsis, the transfer with aquaculture products is suspected. Activity2: In this area maritime traffics is considered a propagation vector for 36% of NIS. Maritime traffics transfer planktonic larvae of the mollusc Rapana venosa in ballast waters, while the most likely vector of introduction of Celleporella carolinensis into the Lagoon of Venice is the hull fouling on ships

• "Shipping & floating structures (all vessels
• Aquaculture
• NotReported

Low availability of abundance data and of impact estimates, and very poor information on main introduction vectors. These gaps may be filled through i) activation of monitoring nets aiming at evaluating the real settlement of non indigenous species, in particular the invasive ones, and their impact, through a standardized methodology; ii) activation of monitoring systems in marine protected areas where human impact is absent or limited; iii) surveillance actions in areas with high probability of introduction such as harbours and aquaculture sites and control actions on ballast water and fouling, and aquarian trade. Italy has adopted the Reg (CE) 708/2007 which will allow a better control of target species introductions due to NIS farming, however, contribution of non voluntary introductions to NIS pressure should be better understood by a better comprehension of farming risks. Italy is in the process of implementation of the UNEP-MAP Mediterranean Strategy for the management of ships' ballast waters and sediments, within the framework of the Barcelona Convention, and is close to ratifying the International Convention for the Control and Management of Ships' Ballast Waters and Sediments (IMO, 2004).