Using DNA Barcoding to Investigate Patterns of Species Utilisation in UK Shark Products Reveals Threatened Species on Sale

Catherine A D Hobbs,Jane Usher,Matthew Bjerregaard Walsh,Robert W A Potts,Andrew M Griffiths

doi:10.1038/s41598-018-38270-3

Abstract

Many shark populations are in decline, primarily due to overexploitation. In response, conservation measures have been applied at differing scales, often severely restricting sales of declining species. Therefore, DNA barcoding was used to investigate sales of shark products in fishmongers and fish and chip takeaways in England. The majority of samples were identified as Spiny Dogfish (Squalus acanthias), which is critically endangered in the Northeast Atlantic and landings have been prohibited (although there is evidence of importation of this species). Significant differences in the species sold between retailer types were also identified, suggesting differing supply chains. The results underline issues surrounding the use of ‘umbrella’ sales terms where many species are labelled with the same designation. This denies consumer choice as purchasers cannot easily avoid declining species or those associated with high levels of toxicants. For the first time in Europe, minibarcodes are also used to identify species from dried shark fins. Despite a small sample size, analysis of UK wholesaler fins identified threatened sharks, including the endangered and CITES listed Scalloped Hammerhead (Sphyrna lewini). This highlights the global nature of the damaging trade in endangered shark species, in which Europe and the UK have a continuing role.

Highlights

Fact that the number of sharks caught from undeclared by-catch and in illegal, unreported and unregulated (IUU) fisheries probably far outweighs those from legal fisheries[8,9]
This requires the international trade in these species to be highly regulated and includes an assessment by the exporting country that the trade will not be detrimental to wild populations[10]. These CITES listings support shark conservation at the broadest, global scale, but a wide range of regional and local regulations on shark fishing have been applied in attempts to halt declines and promote sustainable exploitation. This includes the European Union (EU) where some fisheries are regulated by Total Allowable Catches (TACs) and for species undergoing very steep declines these can be set at zero, largely prohibiting the landings
The meat products were identified as originating from five species: S. acanthias, Mustelus asterias, Scyliorhinus stellaris, Squalus suckleyi and Prionace glauca (Table 1 and Fig. 2)

Summary

Introduction

Fact that the number of sharks caught from undeclared by-catch and in illegal, unreported and unregulated (IUU) fisheries probably far outweighs those from legal fisheries[8,9]. This requires the international trade in these species to be highly regulated and includes an assessment by the exporting country that the trade will not be detrimental to wild populations[10] These CITES listings support shark conservation at the broadest, global scale, but a wide range of regional and local regulations on shark fishing have been applied in attempts to halt declines and promote sustainable exploitation. The use of this DNA region is tied to global efforts to barcode all animal life (http://boldsystems.org/)[13] and has found numerous applications in food authenticity, where DNA sequences from foods can be cross-referenced to databases of references[14] The value of such approaches has been highlighted by high profile investigations that have identified mislabelling, fraud and/or uncovered the sales of endangered species[11,15,16,17,18]. A further aim of this study is to investigate if there is any correlation between label provided and species purchased

Objectives

Methods

Results

Discussion

Conclusion