Invasion
Invasion Description
1st record: Venice/Italy/Lagoon of Venice (1983; Cesari and Pelizzato 1985; Zenetos et al. 2003)
Geographic Extent
Venice/Italy/Lagoon of Venice (1983; Cesari and Pelizzato 1985; Breber 2002; Zenetos et al. 2003); Italy/Po River Delta (Breber 2002); Italy-Slovenia/Gulf of Trieste (before 1996, Crocetta 2011; Crocetta 2012; Lipej et al. 2012); Bar/Montenegro/Adriatic Sea (2015, Petovic et al. 2019)
Vectors
| Level | Vector |
|---|---|
| Probable | Fisheries Intentional |
Regional Impacts
| Ecological Impact | Competition | |
| Ruditapes philippinarum is now the dominant filter-feeder in the lagoons of the northern Adriatic (Pranovi et al. 2008). The native Venerupis decussata has become rare, but has not been eliminated. The native clam is now sold separately, at a higher price, due to 'snob appeal' (Breber 2002). | ||
| Ecological Impact | Herbivory | |
| Ruidtapes philippinarum is now the dominant filter-feeder in the Lagoon of Venice (Breber 2002; Pranovi et al. 2008). | ||
| Ecological Impact | Trophic Cascade | |
| Filter-feeding by Ruditapes philippinarum and other opportunistic species now dominates the Lagoon of Venice's food web (Pranovi et al. 2008), reducing phytoplankton biomass, and shifting the food web to one dominated by benthic filter-feeders (Pranovi et al. 2008). | ||
| Economic Impact | Fisheries | |
| Aquaculture and harvesting of 'wild' Ruditapes philippinarum is now the primary fishery of the lagoons of the northern Adriatic, and the source of 95% of Italian clam production and 90% of the European R. philippinarum harvest (Sladonja et al. 2011). Mechanical harvesting of clams is now the dominant fishery in the Lagoon of Venice (Pranovi et al. 2008). Vibrating rakes have resulted in disturbance and resuspension of sediments, and have adversely affected habitats and other fisheries in the lagoon of Venice. A return to manual harvesting is desirable, but not economically feasible, unless encouraged by government incentives (Nunes and Markandya 2008). | ||
| Ecological Impact | Habitat Change | |
| In the Lagoon of Venice, Italy, R. philippinarum, was the second most important species contributing to bioturbation of sediments (Queiros et al. 2011). However, a much larger factor in bioturbation is probably the effects of mechanical harvesting of the clams with vibrating rakes, which has led to extensive resuspension of sediments and siltation, with negative effects on habitat quality (Pranovi et al. 2008, Nunes and Markandya 2008). | ||