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The aim of the current study was to estimate the genetic parameters for growth and hypoxic tolerance traits in Pacific white shrimp Litopenaeus vannamei at 8 and 13 weeks of ages. Forty full-sib families (including 28 half-sib families) of L. vannamei, which were produced by 26 sires and 40 dams, were obtained by artificial insemination. There were a total of 3,200 tagged shrimps representing 40 full-sib families evaluated for growth and hypoxic tolerance traits in this study (1,600 records were collected at weeks 8 and 13, respectively). The heritability estimates for growth traits were low to medium (0.11-0.23), and the heritability of hypoxic tolerance traits estimated on the observed scales was also low to medium (0.07-0.15), which suggested that selection for increasing growth and hypoxic tolerance traits was feasible. The genetic correlations between growth traits (including carapace length, abdominal segment length, body length, and body weight) within age were generally high, ranging from 0.84 ± 0.06 to 0.95 ± 0.02 (P < 0.05). A significant correlation between growth traits showed that any growth traits can be replaced by other growth traits for indirect selection. The genetic correlation between growth traits and hypoxic tolerance traits within age was low but positive (0.24-0.29), which indicated that selecting for growth traits will cause a positive correlated response in hypoxic tolerance traits. Our results also showed that there was a relatively low genetic correlation between growth traits at different ages (0.18-0.25), which suggested that selection for growth traits in L. vannamei at an early age may not be optimal and should be undertaken at later stages of growth.

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