THE mussels are reared in nurseries ranging in size from five hundred to 1500 square metres, made up of galvanized iron poles planted on the seabed or by floats connected to each other by nylon ropes, stretched below the level of the wave motion, to which the so-called "pergolas" or "rests" on which the mussels grow are knotted.
The rests are in turn formed by plastic nets a tubular sock two in number, placed one inside the other, inside which the single mussels are placed. The nets have more or less large meshes depending on the size of the mussel or mussel (or more commonly called "muscle" in the province of La Spezia).
They are chosen marine areas with favorable morphology and environmental conditions: the lack of storm surges, the depth of the seabed and the underground freshwater currents create the optimal conditions for the growth and development of mussels. In the summer period the breeders provide for the collection, shelling, washing and sorting, while in the winter they carry out the actual maintenance of the nursery, unpacking the remains, replacing the damaged nurseries.
In the summer the breeders provide for the harvesting, ginning, washing and sorting, while in the winter they carry out the actual maintenance of the nursery, dclean up the remains, replace the damaged nurseries, taking advantage of the weight loss, they review the reticle and check the poles or floats.
The iron post lasts 6-7 years, while the mesh, which does not get damaged, is replaced periodically for hygienic reasons as the mussel slips between the meshes and is fixed, sticking with the "byssus", to the external walls of the remains. At least once a year, therefore, it becomes necessary to renew the remains, also redistributing the material which tends to converge in the centre.
The nets used for mussel farming are mostly made of polypropylene, a very resistant plastic, they are lost in the sea, due to neglect or due to storm surges, and accumulate on the seabed, endangering not only the survival of the marine ecosystem, but public health as well.
Waste that also accumulates on the beaches: around 14% of all stranded waste is linked, in general, to the fishing and aquaculture sectors and the vast majority of this is made up of "socks" from mussel cultivation (77%).
It is therefore necessary to promote better management of these nets for mussel farming, with the collection, recycling and use of new materials, with cooperation between associations, research institutions and economic and productive stakeholders.