Differential family-based survival of Pacific White shrimp during communal larval culture and implications for selective breeding programs

Differential larval survival of Penaeid shrimp families when reared communally for any of the mainstream species is widely acknowledged as a likely scenario commercially. However, no scientific data exist in the public domain that quantifies the magnitude of this phenomenon. We report on the differential survival of Pacific White shrimp, Litopenaeus vannamei, families when reared communally during commercial larval rearing and provide explanations of the impacts of such occurrences on managing commercial selective breeding programs. In total 76 families are pooled in two groups of 40 and 36 families and reared through to PL15/16, respectively. DNA microsatellite markers were then used to assign PL15/16 to their family of origin, and the abundance of PL in each family was used to calculate survival rates at a family-based level during commercial communal larval rearing. Calculated survival distributions of 76 families during the larval culture phase ranged from 0 to 100 % with three of the 76 families having no survivors present at PL15/16. Despite all families being stocked into larval culture with somewhat equal representation, only 18 of the 76 families made up 50 % of the population at PL15/16 that would then be stocked into ponds. We found no correlation between the number of nauplii produced per spawning (family) versus the calculated number of PL15/16 alive after the larval rearing phase. Together these three factors have significant implications in Penaeid shrimp selective breeding programs. If populations are not managed appropriately, there is a risk of significant reduction in a programs' effective population size.