Scientists in Singapore have found endangered shark meat in cat and dog food which, unknown to owners, is being fed to pets across the south-east Asian country.
A DNA bar-coding study conducted by scientists at Yale-NUS College in Singapore found that about a third of the pet food samples sequenced contained shark DNA, including from species considered "vulnerable".
Yale-NUS College is a liberal arts college in Singapore established in 2011 as a collaboration between Yale University and the National University of Singapore.
The study, published in Frontiers in Marine Science, made use of DNA bar-coding to test 45 different pet food products from Singapore. They found about a third of all 144 samples contained DNA from sharks, including some from endangered species.
The most common species the researchers identified was the blue shark, followed by the silky shark, which is listed as vulnerable on the International Union for Conservation of Nature’s Red List.
The scientists found that several brands contained endangered species, but listed only vague ingredient lists such as “ocean fish," meaning that consumers are often oblivious. Ground up fish bones and other parts considered offal, are often used in pet food manufacturing.
“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.
The Guardian reported that shark populations are overfished throughout the world, with declines of more than 70% in the past 50 years. As apex predators, they are crucial for the balance of the ocean food chain, and the loss of sharks has had knock-on effects on sea grass beds and coral reefs.
The sale of shark fins has been widely publicised. But a silent contributor, the authors say, is the use of shark products in everyday items such as pet food and cosmetics.
Most pet food products use generic terms such as “fish”, “ocean fish”, “whitebait” or “white fish” in the ingredients list to describe their contents, with some specifically listing tuna or salmon. Others did not indicate fish at all.
“We are on the cusp of starting to lose this ancient group of creatures, species by species, right here, right now,” Andy Cornish, leader of WWF’s global shark and ray conservation programme, told the Environment News Service last year.
“Starting now, we need far greater action by governments to limit fishing and bring these functionally important animals back from the brink,” Cornish said.