Paper short abstract:

An invasive non-native clam, controversial subject of consumption, reveals the ambivalent thought and interspecific relationships of the living beings about the water; the subjective scale of powers of contamination or purification of the fluid throughout its cycle is constantly redefined.

Paper long abstract:

Inseminated for an experience made by the Province of Venice in 1983, Tapes philippinarum has been an unexpected source of prosperity ; it has been also at the origin of changes in the technical, symbolic and legislative appropriation of lagoon resources, and in the understanding of the environment for fishermen and institutions.

While this invasive and non-native species lives at the interface between water and sediment in some polluted areas of the lagoon, thinking it as "good to eat" requires considering beneficial the cycle of brackish water, which the clam filters for feeding, and which influences its growth and organoleptic qualities.

How to determine and discern tangible evidence of pollution or safety while both are invisible in a fluid, in the context of new fishery dynamics on the environmental management policy?

This contribution is fruit of an ethnographic inquiry carried out between 2009 and 2014 among the littoral inhabitants of the Venetian lagoon. The study analyzed the new ways of representing the symbolic bricolage of the testing laboratories, of the role of filtering molluscs or diseases as measurement units, and finally, of the purifying role of seawater or freshwater.

These representations on the water cycle as a constant ongoing process are so essential, that they influence the issue of shellfish licenses and fishing plans established by the Province of Venice. Each human being of this environment gives the clam a political role of health sentinel while building a poetic exchange of solid / liquid evolving.