Response to unintentional selection for faster development associated with inbreeding depression in Crassostrea gigas larvae, resulting from a broodstock selective breeding plan

• Main Authors: Taris, Nicolas, Batista, Frederico, Marissal, Eric, Boudry, Pierre
• Format: Conference Object
• Language: English
• Published: 98 Annual Meeting National Shellfisheries Association, Monterey, CA (USA), 26-30 Mar 2006 2006
• Subjects: Inbreeding depresion; Larvae stage; Genetic variability; Hatchery; Domestication; Genetic; Crassostrea gigas; Oyster; Pacific; Pacific oyster
• Online Access: https://archimer.ifremer.fr/doc/2006/acte-3337.pdf; https://archimer.ifremer.fr/doc/00000/3337/

Direct and indirect consequences of selective breeding in marine bivalves still remain largely unexplored. For species with two-phase life cycle, like the Pacific oyster (Crassostrea gigas), most studies have focused on juvenile and adult stages, but relatively few have focused on juvenile and adult stages, but relatively few have considered the larval stage, especially in a domestication context. We assessed the impact of hatchery practices on larval traits, notably on larval growth (due to the culling of slow growing larvae), by the study of larval progenies. Larvae originating from crosses using parental oysters both from natural beds and from hatchery broodstock which had been selected for adult growth and shell shape for seven generations. A set of three microsatellite loci was used to compare genetic variability in the two parental broodstocks and to establish the relatedness between pairs of individuals within each broodstocks. The mean relatedness was of individuals within each broodstock than in the wild nearly six times higher in the hatchery broodstock than in the wild broodstock. On one hand, our results show a lower mean survival associated with larger variation of growth rate showing a bimodal distribution for the hatchery larval population. On the other hand, a higher success at metamorphosis was observed for the surviving larvae bred from hatchery parents. The results suggest that some of these larvae exhibited inbreeding depression but this was balanced by on overall positive response to selective pressures for larval growth.