Press Release

July 29 , 2013

Incorporated Administrative Agency, Fisheries Research Agency

First demonstration of the existence of genes resistant to a monogenean skin parasite ( Benedenia seriolae ) of the yellowtail

  • Demonstrated the existence of genes resistant to Benedenia seriolae in yellowtail.
  • This is the first instance that a fish species is proven to harbor resistance genes against external parasites.
  • This result allows us to create a yellowtail strain with resistance to B. seriolae and will contribute to reduce the burden of aquaculture producers.

Benedenia seriolae is a serious problem to the yellowtail culture because it causes poor growth and bacterial infections in the yellowtail. The way of removing the parasite is to soak the yellowtail in a freshwater bath. However, this operation requires intensive labor and is therefore burdensome for aquaculture producers.

A research team consisting of the National Research Institute of Aquaculture, the Seikai National Fisheries Research Institute of the Fisheries Research Agency (FRA), and the Tokyo University of Marine Science and Technology focused on the existence of a wild yellowtail showing a higher inherent resistance to B. seriolae in yellowtail population. The team investigated in which region of chromosome the genes contributing the resistance exist from the difference between the yellowtails showing resistance and sensitive to B. seriolae and found that two gene loci contributed to its resistance to external parasites such as B. seriolae. This is the first instance that a fish species is proven to harbor resistance genes against external parasites.

This result allows us to create a yellowtail strain with resistance to B. seriolae and will also accelerate studies on creating new yellowtail strains such as one resistant to bacteria and virus and one that grows fast.

A paper summarizing these results has been published in the American online scientific journal, PLOS ONE, on June 4, 2013 (http://dx.plos.org/10.1371/journal.pone.0064987).

This work was done by “Research on development of techniques of efficiently selecting superior, economic characters from natural fish resources” (Research representative: Kazuo Araki in National Research Institute of Aquaculture), and supported by the Program for Promotion of Basic and Applied Researches for Innovations of Bio-oriented Technology Research Advancement Institution (BRAIN).