A BIOCHEMICAL-STUDY OF THE LARVAL AND POSTLARVAL STAGES OF THE CHILEAN SCALLOP ARGOPECTEN-PURPURATUS

Eggs, larvae and postlarvae of northern scallop, Argopecten purpuratus , were collected from the experimental hatchery of the Estacion Coster a de Investigaciones Marinas (ECIM) of the Pontificia Universidad Cato lica de Chile at Las Cruces to compare their protein, lipid and carboh ydrate composition. In the egg protein, lipid and carbohydrate account ed for 38.2, 34.1 and 1.5% ash-free dry weight (AFDW), respectively. P rotein in the larvae increased from 43.9 to 55.9% AFDW throughout larv al development, and after metamorphosis values varied between 39.8 and 62.1% AFDW, with highest values in 22 day-old postlarvae. Lipids were constant at 20% AFDW during larval development, decreasing to 7.4% AF DW in the premetamorphosis period and increasing again to a constant v alue of 15% AFDW during the 22 days after metamorphosis, then decreasi ng to 2.5% AFDW. Carbohydrate contents were lower than lipid and prote in in all larval stages, varying between 5.1 and 16.5% AFDW; during th e postmetamorphosis period, carbohydrate content varied between 6.6 an d 14.4%, but they were higher than lipid by day 60 after metamorphosis . The premetamorphosis period was characterized by a considerable decr ease in lipid accompanied by a small decrease in protein and carbohydr ate. The planting-out stage (commercial seed) was characterized by a h igh content of protein and a reduced content of lipid in relation to c arbohydrate. This work provides basic information on the role played b y the balance of energy reserves in the metabolism of scallop larvae. (C) 1998 Elsevier Science B.V. All rights reserved.