Stepping Toward Sustainable Aquaculture: Genomic Resource Development to Guide Broodstock Selection and Culture Practices for the California Yellowtail, Seriola lalandi.

Yellowtail aquaculture (Seriola spp.) is established globally with an estimated annual value of $1.3 billion. The Pacific yellowtail, Seriola lalandi, is a strong candidate for future development of offshore commercial aquaculture in southern California. Larval rearing methods for this and other Seriola species are still unreliable, resulting in highly variable survival and physical malformation rates that reduce market value of cultured fish. While genetic resources have been used to improve aquaculture practices for several marine species, few have been developed for S. lalandi. To address this gap, we are developing genomic resources to help improve aquaculture production for this and other economically important Seriola species. Through collaboration between SWFSC and Genome Informatics Facility at ISU, we created a de novo draft assembly of the genome for Seriola lalandi. DNA sequencing was conducted using the Illumina HiSeq 2500, resulting in approximately 1.2 billion raw reads, for estimated 160X coverage of the 685Mb genome. CEGMA analysis indicated that the MaSurCA assembly contained 93% of the Core Eukaryotic genes. Transcriptome analyses were also conducted to characterize physiological system development and examine growth heterogeneity. Gene expression was measured in three replicates of pooled larval samples at 2, 7, and 17 days post hatch. Sixty million reads, on average, were obtained per replicate. Genes of related function were sorted into clusters; those found at high frequency in the differential gene expression set were identified. This presentation will summarize highlights from these projects, and discuss results of these analyses, to date.