THE IMPORTANCE OF GONADAL DEVELOPMENT ON LARVAL PRODUCTION IN PECTINIDS

In the natural environment and in hatcheries, development of pectinid eggs varies considerably between species, between populations of a giv en species, and between hatcheries. In addition, results observed in h atcheries vary considerably from one year to another and are therefore not reproducible, which is detrimental to the success of this type of aquaculture venture. On the basis of results obtained both in situ an d in the laboratory for Argopecten purpuratus from Chile and for Pecte n maximus from France, an attempt was made in this study to determine factors leading to poor quality of eggs of these pectinids. Nutrient l evel available in the gonad seems to be the main factor involved. In p articular, absence or low levels of polyunsaturated fatty acids such a s 20:4 (n-6), 22:6 (n-3), and 20:1 (n-9) appear to be detrimental to p roper larval development. Similarly, sterols are also necessary to ens ure a harmonious larval existence because this molecule is used extens ively by the embryo in building cellular membranes. The addition of th ese compounds to artificial feed or selection of new algal feeds seems to be a priority if the dependability of Pectinid hatcheries is to be increased.