FISH-BOL and seafood identification: Geographically dispersed case studies reveal systemic market substitution across Canada

Abstract

Background and aims. The Fish Barcode of Life campaign involves a broad international collaboration among scientists working to advance the identification of fishes using DNA barcodes. With over 25% of the world's known ichthyofauna currently profiled, forensic identification of seafood products is now feasible and is becoming routine.

Materials and methods. Driven by growing consumer interest in the food supply, investigative reporters from five different media establishments procured seafood samples (n = 254) from numerous retail establishments located among five Canadian metropolitan areas between 2008 and 2010. The specimens were sent to the Canadian Centre for DNA Barcoding for analysis. By integrating the results from these individual case studies in a summary analysis, we provide a broad perspective on seafood substitution across Canada.

Results. Barcodes were recovered from 93% of the samples (n = 236), and identified using the Barcode of Life Data Systems “species identification” engine (www.barcodinglife.org). A 99% sequence similarity threshold was employed as a conservative matching criterion for specimen identification to the species level. Comparing these results against the Canadian Food Inspection Agency's “Fish List” a guideline to interpreting “false, misleading or deceptive” names (as per s 27 of the Fish Inspection regulations) demonstrated that 41% of the samples were mislabeled. Most samples were readily identified; however, this was not true in all cases because some samples had no close match. Others were ambiguous due to limited barcode resolution (or imperfect taxonomy) observed within a few closely related species complexes. The latter cases did not significantly impact the results because even the partial resolution achieved was sufficient to demonstrate mislabeling.

Conclusion. This work highlights the functional utility of barcoding for the identification of diverse market samples. It also demonstrates how barcoding serves as a bridge linking scientific nomenclature with approved market names, potentially empowering regulatory bodies to enforce labeling standards. By synchronizing taxonomic effort with sequencing effort and database curation, barcoding provides a molecular identification resource of service to applied forensics.

Keywords::

• DNA barcoding
• cytochrome c oxidase subunit I
• seafood mislabeling
• market substitution
• Barcode of Life Data Systems

Acknowledgements

The authors dedicate this paper to the investigative reporters who helped make it possible and the quality journalism they produced in relation to the individual case studies. The authors highlight the key role that ethical reporting plays in raising consumer awareness and driving social change. They are very grateful to Greg Sadler (Canadian Broadcasting Corporation, CBC Marketplace), Alain Roy (L'épicerie Société Radio Canada), Larry Pynn (The Vancouver Sun newspaper), Amy Luft (Montreal CTV TV station), and Susan Sampson (The Toronto Star newspaper) for sample collection and shipping. Permission has been given by these organizations to publish the data derived from their samples. They offer special thanks to Jake Lowenstein for a stimulating review and Teri Crease for a helpful discussion on the use of the contingency test. The authors acknowledge Jonathan Deeds, Sergios-Orestis Kolokotronis, Rosalee Hellberg and David Schindel for comments on an earlier version of this manuscript. We also offer special thanks to Jason Agius who provided the following comments and clarifications as this article was going to press: 1) the CFIA recently issued an “Industry Notice” regarding the labeling of Pacific Salmon [http://www.inspection.gc.ca/english/fssa/fispoi/commun/20101220e.shtml]; 2) according to the Fish List “halibut” would be acceptable for both Atlantic or Pacific halibut and the geographic name of harvest “Alaskan Halibut” would be considered acceptable as well [see: http://www.inspection.gc.ca/english/fssa/fispoi/product/comnome.shtml & http://www.inspection.gc.ca/english/fssa/labeti/guide/ch4ae.shtml#a4_20 (4.20.1 Geographical terms)]; 3) neither Seriola lalandi nor Seriola quinqueradiata are on the Fish List, but Seriola sp. is included for Amberjack and the Fish List should be amended accordingly; 4) similarly, Oreochromis aureus is not yet on the Fish List; while 5) Pagrus major is also known as Silver Seabream, Japanese Seabream or Genuine porgy on the Fish List. Daniel Carvalho (Universidade Federal de Minas Gerais), Heather Braid, Suresh Naik and Evgeny Zakharov (University of Guelph) aided work in the laboratory. The BOLD informatics team provided efficient database support. The CCDB acknowledges support from Genome Canada (through the Ontario Genomics Institute), the Natural Sciences and Engineering Research Council of Canada (NSERC), and the Ontario Ministry of Research and Innovation (MRI).

Declaration of interest: The authors report no conflicts of interest. The authors contributed equally to the manuscript and they alone are responsible for the content and writing of the paper. D.S. was supported by funding from the Alfred P. Sloan Foundation to MarBOL. S.B. was supported by funding from the Natural Sciences and Engineering Research Council of Canada (NSERC).