Rapid identification of the north-western Pacific billfish species using quantitative real-time polymerase chain reaction techniques

ABSTRACT

Billfishes are important fishery resources traded and consumed worldwide. As morphological traits are usually removed during processing, molecular methods are applied to identify billfish products. In this study, the approaches of quantitative real-time PCR were developed to identify the six billfish species (Istiompax indica, Istiophorus platypterus, Kajikia audax, Makaira nigricans, Tetrapturus angustirostris and Xiphias gladius) widely distributed in the north-western Pacific Ocean. The developed singleplex systems showed high fidelities to each of the six species via either examining the ΔCt values or melting curve patterns. For samples containing multiple species, individual species are identifiable by a quantitative real-time PCR assay that includes all the singleplex systems. A multiplex system was also developed to identify unknown samples composed of a single species. The methods developed in this study provide a fast and high-throughput manner to identify the north-western Pacific billfish species when morphological traits are unavailable, such as in processed products.

RESPONSIBLE EDITOR:

• Michael Maia Mincarone

KEYWORDS:

• Billfish identification
• food forensic
• melting curve analysis
• quantitative real-time PCR

Acknowledgements

We thank Dr Wei-Jen Chen for useful discussion, and the Taitung Fisheries Research Institute for sample collection. We also thank Robert Anthony Campbell for the English editing.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Po-Shun Chuang http://orcid.org/0000-0003-3792-5421

Additional information

Funding

This work was supported by the Ministry of Science and Technology, Taiwan [grant number MOST 104-2611-M-002-004].