REPRODUCTION AND RECRUITMENT IN PECTEN-MAXIMUS L

Recruitment in scallop, Pecten maximus L., appears to be highly variable. Analysis of data concerning spawning intensity, larval and juvenile abundance and the strength of die two-year class, indicates that the sequence maturation-spawning-larval life is the most determinant for recruitment. The goal of the present paper is to elucidate the processes responsible for variability at this level. The principal results, acquired with experimental rearings and microscopical investigations of the gonad and the emitted oocytes are as follows : i) the emitted oocytes, during the spawning season, vary in quality, inducing different hatching successes and larval abnormalities; ii) microscopically, the oocytes show ultrastructural abnormalities linked to the atresia process and variability in lipid content; and iii) the origin of this variability is found in the environmental conditions during maturation, specially temperature.