Etude technique et financière sur la filière de production intensive de la palourde en marais

The development of the intensive method for producing Manila clams (Ruditapes philippinarum) in marshes is the result of five years of research at the Ifremer station in Bouin. The method developed here produces a clam of commercial size in 19 months instead of two to three years. Batches of intensively farmed clams are more homogenous than batches of extensively farmed clams. The many advantages of this method suggest that the clam farming profession would be very interested in these new culture techniques. Before considering technology transfer, it is necessary to carry out an economic study. The project retained for this study concerns the installation of a new farm that is to produce 15 or 20 t of commercial-size clams (>35 mm) in Bourgneuf Bay. The technical and financial study conducted in this set-up showed that this type of project is not presently feasible. Even after accounting for potential technical improvements, the cost of producing an intensively farmed clam is higher than its sale price under the current market conditions and the current payment schedules (loans, salary) that were used in the study. The intensive farming method could, however, be of interest for existing clam farms that wish to diversify their practices. In particular, farms that already have intensive pre-grow-out systems could benefit from anticipated increases in productivity through phytoplankton production.