Abstract

The Oyster parental stock was taken from the 1998 natural spatfall from the wild population of Ostrea chilensis at the Quempillen River Estuary, located at Chiloe Island, southern Chile. From a cohort of 34 months of age 5232 oysters were monitored for the traits shell length and live weight. Selection was carried out applying a selection intensity of + 1.7 for the trait live weight, using a control group. The conditioning was carried out in 5 tanks of 120 L, 3 of them containing high selected lines and other 2 control lines of oysters. A highly significant correlation (0.76, p<0.001, N=5232) was found between the traits live weight and shell length. Spat from the 3 selected subgroups and 2 control groups were obtained. Plastic collectors with the spat attached were placed in a common rearing tank. Shell length was monitored after 6 and 16 weeks of age in 200 juveniles of each selected and control lines. The ANDEVA results show a significant difference (p<0.05) between the shell length of the selected and control groups at 6 and 16 weeks of age. Also, a significant response to selection was obtained even when selection was applied for the trait live weight at 34 m-old. These results confirm those obtained in an earlier study using the same natural oyster population from Quempillén.