Production artificielle de naissain de coquilles Saint-Jacques Pecten maximus (L.) : Analyse des facteurs affectant la croissance larvaire

The analysis of the Pecten maximus larval productions carried out between 1982 and 1986 in the framework of the repopulating program of the roadsted of Brest demonstrated the existence of a number of factors affecting larval growth in hatcheries: - Larval growth shows important seasonal fluctuations. It is minimal in February-March (3 to 4 µm.D-1) and maximal in June (6 to 8 µm.D-1). The growth of larvae from conditioned spawners does not differ from that of larvae from mature genitors collected in their natural habitat. Growth is favoured by an unknown factor present in sea water and held with a filtration of 0,2 µm. - The growth of the larvae cultivated in slack water in flat bottom ponds is higher than that of the larvae cultivated in bubbling water in cylinder-shaped ponds with a conical bottom. The average sizes of the pediveligers show a difference of about 10 µm. - Larvae whose growth was inferior to the average growth of a batch have a reduced metamorphosis and survival rate. The consequences of these observations on the management of a king scallop hatchery are discussed.