Morphological and biochemical characterizations of the great scallop Pecten maximus metamorphosis

In order to characterize Pecten maximus metamorphosis within a hatchery env ironment, the relationships existing among the various larval rearing param eters, the biochemical composition of the larvae and metamorphosis have bee n determined. Metamorphosis levels are correlated with the percentages of d ouble ring larvae, as well as with the larval lipid content. A multiple reg ression incorporating the percentage of double ring larvae and larval lipid content shows that these two combined parameters explain 50 % of the total metamorphosis variance, with an equal relative importance for each of them . In an attempt to identify other possible endogenous markers, the kinetics of biogenic amines were also examined throughout larval and post-larval de velopment. A steady increase in serotonin and dopamine levels was recorded during larval development while a sudden decrease in both molecules was not ed du ri ng metamorphosis. It is suggested that these two amines may be use d as indicators of larval competence for FI maximus metamorphosis. (C) 1999 Academie des sciences / Editions scientifiques et medicales Elsevier SAS.