Anyone for shark and chips?

It’s often said that history has a way of repeating itself. In 2013, there was public outcry when horse meat was passed off as beef by a number of UK supermarket chains. Now, University of Exeter academics have revealed that high street fish and chip shops routinely serve unwitting customers shark and chips.

Using DNA barcoding techniques, scientists were able to identify species sold under generic names such as huss, flake, and rock salmon, finding a majority came from sharks which are protected because of declining numbers.

The study analysed over 100 samples from chip shops and from fishmongers, mostly in southern England, as well as 10 fins from a wholesaler that sells them to restaurants and specialist supermarkets. The findings of the Exeter researchers, published in Scientific Reports, showed that of the 78 samples on sale at chip shops in 2016 and 2017, about 90% came from Squalus acanthias (spiny dogfish). Spiny dogfish, classified as endangered in Europe by the International Union for the Conservation of Nature’s red list, was illegal to catch in the EU until 2011 but the fish is now permitted to be sold as bycatch – when it is brought up in nets that target other species.

University of Exeter academics have revealed that high street fish and chip shops routinely serve unwitting customers shark and chips

Of the 39 fresh and frozen samples obtained from fishmongers, about half were assigned to Mustelus asterias (starry smooth hound). The researchers were also able to determine that Sphyrna lewinin (scalloped hammerhead) was present in three of 10 dried shark fins on sale in the UK. The team reported that wholesalers were charging up to £86 for just three shark fins.

Nursehounds and blue sharks were also species of endangered sharks commonly being sold. Commenting on the findings of the study, Simon Walmsley, Chief Marine Adviser at WWF, declared: “Endangered shark species shouldn’t be ending up on people’s plates as their weekend takeaway, particularly the spiny dogfish which is vulnerable and threatened with extinction.”

The endangered scalloped hammerheads – identified through genetic testing – were destined for the Asian restaurant market, which considers shark fin soup and related dishes a delicacy. Dr Andrew Griffiths, another of the paper’s authors, commented: “The discovery of endangered hammerhead sharks highlights how widespread the sale of declining species really is – even reaching Europe and the UK.”

Nursehounds and blue sharks were also species of endangered sharks commonly being sold

Although the government allows many shark species to be passed off under long-used umbrella names – including rock eel – the researchers are calling for more accurate and stringent food labelling so people know exactly what they are consuming. Catherine Hobbs, the first author of the paper, stated: “It’s almost impossible for consumers to know what they are buying.” The University of Exeter researcher added: “People might think they’re getting a sustainably sourced product when they’re actually buying a threatened species.”

When commenting on public perception, Griffiths said: “I spoke to customers who were totally shocked they were eating shark… you just cannot tell.”

Deliberately confusing customers can pose a health risk. “There are also health issues. Knowing what species you are buying could be important in terms of allergies, toxins, mercury content and the growing concern over microplastics in the marine food chain” said Hobbs. The risk to pregnant women is of particular significance, owing to the high levels of mercury in the meat.

Although the government allows many shark species to be passed off under long-used umbrella names, the researchers are calling for more accurate and stringent food labelling 

The widespread passing off of horse meat as beef, followed by the revelation that your fish and chips could actually be shark, highlights the rise in high-profile food fraud scandals in recent years. Going forward, genetic tools which can determine swiftly and quickly the provenance of a piece of meat or fish will be a powerful weapon against this practice.