Differences in larval growth among families of Penaeus stylirostris Stimpson and P. vannamei Boone

Abstract. Full-sib families of Penaeus stylirostris Stimpson and Penaeus vannamei Boone were grown under controlled conditions in five experiments. Total length of shrimp larvae was measured at the following substages: protozoea one, mysis one and postlarva one. Analysis of variance showed that families differed significantly in size in all experiments at all substages tested. The average size possessed by a group of larvae early in development was significantly correlated with the size obtained in the later stages in P. siylirosiris , but not in P. vannamei . The component of variance in size due to family differences was determined and used to estimate heritabilities of size at the three larval substages in both species. Estimated heritabilities were higher for P. stylirostris than P. vannamei . In P. vannamei . the hcritability of size is greater for the protozoea and postlarval stages than the mysis stage.