MULTIPLE-LOCUS HETEROZYGOSITY, PHYSIOLOGY AND GROWTH AT 2 DIFFERENT STAGES IN THE LIFE-CYCLE OF THE CHILEAN OYSTER OSTREA-CHILENSIS

A random sample of 150 individuals of a laboratory-produced cohort of Ostrea chilensis Philippi, 1845 was taken at 10 and 36 mo of age to es timate physiological variables and individual heterozygosity using 4 l oci (Lap, Pgi, Pgm and Ca). Juveniles of 10 mo of age showed a mean D value of 0.134 (p > 0.05) and a positive correlation between oyster si ze and multiple-locus heterozygosity (MLH) (p < 0.05). Also, there was a positive correlation (p < 0.05) between ingestion rate, absorption rate and MLH. A negative correlation between excretion rate (p > 0.05) , oxygen consumption rate (p < 0.05) and MLH was found. The K-2 value (standardized net growth efficiency) was positively correlated (p < 0. 05) with MLH. At 36 mo a heterozygote deficiency was present with a me an value D = -0.431 (p < 0.05). No relationship between standard dry w eight and MLH and also a negative correlation between the scope for gr owth and MLH were found. The oxygen consumption and excretion rates al so showed an increase in large size individuals. The slopes for filtra tion and excretion rates against MLH were negative and not statistical ly significant. However, ingestion and absorption rates showed signifi cant (p < 0.05) decrease with an increase in heterozygosity. The resul ts seem to indicate that within sexually immature individuals of O. ch ilensis, a positive correlation between growth rate and MLH can be fou nd, while in adults the higher energy allocation for reproduction prec ludes the detection of this relationship.