DNA Tests Reveal Traces of Endangered Shark in Various Pet Food Brands

A study has revealed that several brands of cat and dog food show signs of endangered shark DNA. The endangered species is often obliquely listed as “ocean fish” as well as other code names on the ingredients label, so pet owners are oblivious as to whether they’re feeding their pets the meat of an endangered marine animal.

“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 study authors, Ben Wainwright and Ian French, of Yale-NUS College.

The word “shark”, is not specifically written on any pet food ingredient label. Instead, companies label the illegal ingredient “ocean fish”, “white bait” or “white fish”, while some companies didn’t indicate any fish as an ingredient. Of the samples tested in the study, 31% contained shark DNA. The study did not mention brands by name.

The study, published Friday in the open science platform Frontiers in Marine Science, says that the global demand for shark fins, liver oil, and meat has caused a serious decline in the animal’s population. Shark populations have decreased by 71% since 1970, according to widely-accepted research.

Declining shark populations have a devastating effect on the environment and the ecosystems the shark inhabits. As an apex predator, changing the distribution of their prey causes a decline in coral reefs and seagrass beds. Taking a shark out of its ecosystem also affects fisheries, causing groupers to thrive in their absence and gobble up surrounding herbivores.

The most commonly identified species in pet food included blue shark, silky shark, and whitetip reef shark, according to the study.

It is not illegal to mislabel shark as an ingredient on a product label, and the misleading practice is reportedly common. Shark liver oil, referred to as squalene, is used in an array of cosmetic products, including anti-aging creams, lotions, deodorants, hair conditioners, makeup, sunscreen, and facial cleansers.

Shark fin is a highly-prized meat in some cultures, but the rest of the shark’s carcass is of a much lower value in the meat market, making it a cheap source of protein to be used elsewhere, such as for dog and cat chow.

In 2019, researchers at the University of Exeter discovered sharks were being sold by fish and chip shops in the UK. The shops were using generic names, in this case “husk”, “rock”, “flake” and “rock salmon”. The ingredients turned out to be spiny dogfish, an endangered shark species.

Until 2011, it was illegal to catch spiny dogfish in the EU, but has since been allowed to be sold as bycatch.

“It’s almost impossible for consumers to know what they are buying,” said Catherine Hobbs of the University of Exeter, and first author of the study. “People might think they’re getting a sustainably sourced product when they’re actually buying a threatened species.

“There are also health issues,” added Hobbs. “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.”