APPLYING GENETIC AND GENOMIC TOOLS TOWARD UNDERSTANDING BROODSTOCK DYNAMICS AND LARVAL DEVELOPMENT IN THE CALIFORNIA YELLOWTAIL, Seriola dorsalis.  

In the Pacific, the yellowtail, Seriola dorsalis, is a strong candidate for future development of offshore commercial aquaculture in southern California. However, larval rearing methods for this and other Seriola species are limited by variable survival rates and physical malformations that impact commercial aquaculture by reducing the market value of fish. Advances in genetics have been used to improve aquaculture practices for a handful of valuable marine species, but few resources have been developed for S. dorsalis. To address this gap, we are developing genetic resources and tools for S. dorsalis  using a multifaceted  approach that  includes: evaluating spawning dynamics in broodstock populations through parentage/kin analyses, and looking for selction signals on genotypes across larval stages. Spawning group dynamics are key for the selection and maintenance of broodstock populations; this includes determining reproductive output of individual brood fish, parental contribution to deformity prevalence or growth variation, and maintenance of genetic diversity. Microsatellite-based parentage analyses have revealed that: 1) typically only two females contribute to each spawning event, 2) a larger number of males (7+) contribute to each event, and 3) certain broodstock fish disproportionately contribute to deformities in offspring.  Results of these analyses, to date, will be presented.