ABSTRACT: 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 estimate physiological variables and individual heterozygosity using 4 loci (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 size 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 K₂ value (standardized net growth efficiency) was positively correlated (p < 0.05) with MLH. At 36 mo a heterozygote deficiency was present with a mean value D = -0.431 (p < 0.05). No relationship between standard dry weight and MLH and also a negative correlation between the scope for growth and MLH were found. The oxygen consumption and excretion rates also showed an increase in large size individuals. The slopes for filtration and excretion rates against MLH were negative and not statistically significant. However, ingestion and absorption rates showed significant (p < 0.05) decrease with an increase in heterozygosity. The results seem to indicate that within sexually immature individuals of O. chilensis, a positive correlation between growth rate and MLH can be found, while in adults the higher energy allocation for reproduction precludes the detection of this relationship.

KEY WORDS: Growth . Heterozygosity . Ostrea chilensis . Oyster . Physiology

Published in MEPS Vol. 134 (1996) on April 25
ISSN: 0171-8630. Copyright © Inter-Research, Oldendorf/Luhe, 1996