Tracing the Origin of Seafood

Tracing the Origin of Seafood

On average 30% of (uncontrolled) seafood is mislabeled.

Published: January 2017. With more and bigger fishing boats, highly technological but very wasteful fishing methods (bycatch), and more people to feed, it is becoming clear that we are simply emptying out the oceans. It is estimated that marine vertebrate populations have declined by 49% between 1970 and 2012 (WWF) and 90% of global fisheries are fished to their maximum or beyond (FAO). This is an issue that might lead to a global crisis as healthy oceans are important not only to feed humans, but also to keep the entire ecosystem in balance (O2 production, CO2 absorption, climate regulation, effects on other species).

The Marine Stewardship Council (MSC) is an international non-profit organisation working on the problem of unsustainable fishing and safeguarding seafood supplies for the future. In order to trade MSC-certified seafood, the supermarket, fishmonger or seafood restaurant must have a valid Chain of Custody certificate. Regular audits ensure that the companies meet the requirements that certified seafood is only purchased from certified suppliers and that it is identifiable at all times, separated from non-certified seafood and sold with the correct paperwork. This allows you and me as customers to choose sustainable seafood labeled with the blue MCS logo.

As in previous years, the MCS recently commissioned the Wildlife DNA Forensics unit at Science and Advice for Scottish Agriculture (SASA) to conduct DNA tests on a random sample of 257 MSC labelled seafood products from 13 different species and 16 different countries.

In order to precisely identify the species of fish, the labs used different methods, the major one being DNA barcoding. Here a region of the genome known to be different and unique between species is read and the sequence compared to a database of defined barcodes. In this study the mitochondrial DNA Cytochrome oxidase subunit I gene was used and compared against the BOLD database. This publicly available repository already covers over 168,000 different animal species. As an example: A sample from a fish could be put through the laboratory procedure of isolating the DNA, amplifying and sequencing the specific genomic region on a standard Illumina sequencing machine; the resulting sequence of DNA letters is compared against all stored sequence signatures in the database and might result in the identification of the Atlantic Cod.


MSC video
The current results are encouraging: 255 correctly labelled products (99.2%), 1 product without result, 1 wrongly labelled product. The latter was a Northern Rock Sole accidently sold as the very similar Southern Rock Sole.
While other studies have shown that around 30% of all global seafood is currently mis-described or mislabelled (Pardo 2016), tests and results like these help to enforce protection of vulnerable species, encourage sustainable and honest fisheries, and establish consumer trust.

Sources and Links:

  • MSC article
  • Short German version of the article
  • Publication by the MSC with more background information
  • Blog Post about the MSC test
  • National Geographic on sustainable fishing
  • Pardo, M. Á., et al. (2016) Misdescription incidents in seafood sector. Food Control 62, 277–283.
  • Featured image: MSC