Aquaculture Genomics: Applications to Asian seabass and arowana

Fishes are the biggest group of vertebrates: the number of their species exceeds that of the four other vertebrate groups combined. Only a small portion of the ca. thirty thousand fish species are used in commercial aquaculture and for most of them, culture technologies were developed empirically. Research-based aquaculture is expected to speed up the process of selection, allowing for rapid development of elite lines that are available only for a few fish species today.

We have been working on the improvement of traditional aquaculture procedures and cultured fish species through the use of molecular and genomic tools for over a decade. In my presentation, I will describe two of our project: 1) producing elite lines of Asian seabass through selection assisted by molecular tools; and 2) understanding the breeding biology of Asian arowana.

The Asian seabass (or barramundi; Lates calcarifer) is a food fish species that occupies a vast geographic region that extends from Western Australia through South-East Asia to Northern India. This catadromous, protandrous hermaphrodite is born in the brackish water of coastal regions, matures in freshwater as a male, and eventually changes its sex into a female.

In collaboration with two partners, we have started a marker-assisted selection program on Asian seabass in 2004 that has yielded fish with increased growth rates. In 2012, we embarked on a Genome Project in order to develop tools allowing for genomic selection of additional traits.  Currently, we are working on sequencing the transcriptome of the Asian seabass that will allow us to quantify expressed gene sets in various situations and will also seed the Seabass Genome Project. I will describe the current status of this work at both levels, and show examples for the application of the resulting tools. In addition, I will also provide an outlook for developments that are expected in the near future.

The Asian arowana (Scleropages formosus) is an extremely expensive, endangered ornamental fish species. It has an unusual breeding biology that involves the production of up to 70-80 giant eggs and increased protection of larvae through mouth brooding. In collaboration with a commercial farm, we have been studying the unusual reproductive biology of the species for the past eight years. Through the use of molecular approaches, we gained a better understanding of the breeding process and obtained information that allowed the farm to improve their aquaculture technology. In my presentation I will describe some of the most exciting findings of this project.