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The DNA of pet food has been found to contain the DNA of sand tiger sharks, making them vulnerable.Stefan Sauer/Zuma Press
This story was originally published in the Guardian and is reproduced here as part of the Climate Desk collaboration.
Pet food containingUnwitting owners are feeding endangered sharks to their pets, a study revealed.
Scientists found that several brands contained endangered species but listed only vague ingredients such as “ocean fish,” meaning that consumers are often oblivious.
“The majority of pet owners are likely lovers of nature, and we think most would be alarmed to discover that they could be unknowingly contributing to the overfishing of shark populations,” said the study authors, Ben Wainwright and Ian French, of Yale-NUS College, Singapore.
Overfishing of shark populations has led to a decline in their numbers by more than 70% over the past 50 years. Sharks are essential for the balance of the ocean food chains as they are apex predators. Their loss has had ripple effects on seagrass beds, coral reefs, and other marine life.
The sale of shark fins has been widely reported. The authors point out that shark products are used in everyday items, such as pet food, cosmetics, and household cleaning products.
The scientists tested 45 pet foods from 16 brands in Singapore using DNA barcoding. Most products used generic terms such as “fish,” “ocean fish,” “white bait,” or “white fish” in the ingredients list to describe their contents, with some specifically listing tuna or salmon. Some products did not include fish.
Of the 144 samples sequenced, 45—roughly one-third—contained shark DNA. Blue shark, silky shark and whitetip reef shark were the most commonly identified species. The silky shark and the whitetip reef shark are listed as “vulnerable” in the International Union for Conservation of Nature’s (IUCN) Red List.
Products containing DNA of the sicklefin weasel shark, the Caribbean sharpnose shark, and the sand tiger shark—all vulnerable species—were also identified.
The authors suggest that the meat could be extracted from shark carcasses, which would then be discarded after the valuable fins have been removed. This could also reflect a growing shark meat market. They call for better labelling of ingredients so that pet owners know what they are feeding their pets and where it came.
Dr Andrew Griffiths is an ecologist from the University of Exeter. The latest work follows research by his group and others that showed shark DNA in food products intended for human consumption. Spiny dogfish, hammerhead shark meat in fish and chip shops.
He said that pet foods are not subject to specific labelling rules, so a wide range of vulnerable species could be legal included. “There aren’t any specific rules against it,” he said. “You could be unwittingly getting just about any fish.”
Griffiths stated that shark meat is not only a lucrative source of protein, but it can also be traded for high-value shark fins. “Lots of people don’t want to eat it,” he said. “So you can’t necessarily sell it through other supply chains. It surprises people that these things can turn up on their pet’s plate.”
The journal publishes the findings. Frontiers in Marine Science.
