DNA tests reveal endangered shark species in pet food

Pet owners may be unintentionally feeding their animals with meat from endangered shark species, a new study has found.

Curious about the vague ingredient lists on pet food packages — which trumpet contents like “fish,” “ocean fish” and “white bait” — researchers at Yale-NUS College in Singapore said they wanted to investigate what people are really feeding their beloved pets.

The scientists used DNA barcoding to determine whether there was shark DNA in 45 different pet food products from 16 different brands in Singapore, publishing their findings on Friday in Frontiers in Marine Science. 

“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,” authors Ben Wainwright and Ian French, from Yale-NUS College, said in a statement.

Of the 144 samples they ended up taking, the researchers said that 31 percent contained shark DNA — and the most identified species were the blue shark (Prionace glauca), followed by the silky shark (Carcharhinus falciformis) and the whitetip reef shark (Triaenodon obesus). Both the whitetip reef shark and the silky shark are listed as “vulnerable” in the International Union for Conservation of Nature Red List, the scientists noted. 

“None of the products purchased listed shark as an ingredient, using only generic catch-all terms such as ‘fish’, ‘ocean fish’, ‘white bait’ or ‘white fish’ to describe their contents,” the authors said.

The Yale-NUS College study follows up on a 2019 study in Conservation Genetics that found a robust presence of shark meat in pet food samples collected around the U.S. — inspiring the researchers to evaluate Asian products as well.

Given their findings, the scientists urged policymakers to implement global standards for pet food labels, in order to curb the overexploitation of endangered shark species. They stressed the importance of avoiding “vague catch-all terms in ingredients lists,” with hopes of granting consumers the opportunity to make informed choices.

As apex predators in the oceanic food chain, sharks are crucial for the maintenance of healthy marine ecosystem, according to the scientists. But a growing shark fin and meat trade is jeopardizing shark populations, with an estimated 100 million sharks are killed annually, the authors noted.

Shark meats are also found as a “silent contributor” in everyday items like cosmetics — including shark-derived squalene oil in beauty products, the scientists said.

“Shark populations are overfished throughout the world, with declines of more than 70 percent in the last 50 years documented,” Wrainright and French added. “This is indicative of the current lack of regard in which we hold our oceans.”