Genetic Parameters of Growth and Survival in the Tetraploid Larvae of Pacific Oyster Crassostrea gigas

Crassostrea gigas is distinguished by its robust fertility, adaptability to various environmental conditions, and rich nutri-tional profile, which render it a cornerstone of the global shellfish market. Tetraploid oysters, in particular, is a pivotal role within the oyster industry, however, their growth and survival characteristics need to be improved. This study aimed to assess the viability of enhancing the growth and survival characteristics of tetraploid C. gigas through genetic selection. This was achieved by investigating the heritability and genetic correlation of growth and survival at various stages of C. gigas development. Genetic parameters were assessed based on in-group correlations in 28 full-sib families during the larval stage (days 3, 8, 13, 18, and 23 after fertilization). The heritability of larval shell height and shell length ranged from 0.50 to 0.71 and 0.44 to 0.71, respectively, and varied with age. The heritability of larval survival was 0.40 – 0.64, indicating that it is viable to enhancelarval survival through selection. The genetic correlation between the growth traits of larvae at different ages was highly positive (0.959 – 0.999), indicating that the selection of a single growth trait could cause the positive response of other growth traits. However, the genetic correlation between larval survival and growth traits was low, showing a significant negative correlation (−0.198 – −0.293) at day 23 of age, suggesting thatselecting for enhanced survival in tetraploid C. gigas may result in a detrimental impact on growth traits.The results are helpful for future researches to evaluate the genetic parameters related to growth and survival traits in juvenile and adult stages of the tetraploid family of C. gigas, which can provide further guidance for the selection of tetraploid C. gigas.