Import and Export: Successes and Flops
- Pp. 239-255 (17)Riccardo Cattaneo-Vietti, Mauro Doneddu and Egidio Trainito
In the mid-19thcentury, European and North American shellfish farmers began the search for "new" bivalves of potential commercial interest, suitable for farming and more resistant to epi-demics. Some of these imports have had great success (like the Japanese oyster or the Philippine clam), but often this kind of trade has caused serious problems: the introduction of a species in a "new" environment is, in fact, a high ecological risk action. It is, in fact, clear that the continuous transport of stocks of living organ-isms from a production area to another, practically all over the world, favours the spread of pests and the diffusion of invasive species which may cause damage to economic activities and in par-ticular to aquaculture. Moreover, in the Mediterranean Sea, the Su-ez Canal has facilitated the spread of numerous molluscs which, over time, have created stable Mediterranean populations, entering sometimes in competition with the native flora and fauna. </p> <p> In freshwaters, the most famous case is the diffusion in Western Europe and North America of the zebra mussel, an invasive bivalve which causes very serious economic problems, obstructing indus-trial and civil pumping water stations in lakes and rivers.