Imagine wandering into your local supermarket and you find it’s selling lion or tiger steaks. You’d probably be surprised. Now imagine the meat in question is just labelled 'cat' or 'felid' – you wouldn’t even know which species it came from.
But that’s the situation researchers from the University of North Carolina have revealed in a study published in the journal Frontiers in Marine Science that examines the selling of shark meat. They visited different food stores and bought and DNA barcoded 29 different products, almost all of which were simply labelled as 'shark', to determine what species they actually came from.
- Are sharks losing their deadliest weapon?
- When great white sharks vanished from False Bay, it triggered something disturbing
Sharks are the oceans’ apex predators, and many of the more than 500 species are threatened with extinction.
But Savannah Ryburn and colleagues nevertheless found great and scalloped hammerhead shark – both assessed as Critically Endangered by the IUCN Red List – on sale, along with nine other species.
And this isn’t just a wildlife conservation issue, Ryburn points out. "Scalloped hammerhead shark has very dangerous levels of mercury in it,” Ryburn says, “so if you have no idea what you’re buying, you don’t have any choice as to how much mercury you are consuming.”
Sharks at the top of the food chain – such as hammerhead or mako sharks – are more likely to ‘bioaccumulate’ larger quantities of mercury than sharks such as the bonnethead, which mainly preys on blue crabs.
Ryburn says, at the very least, US authorities should consider requiring retail outlets to identify what species of shark is being sold.
Going back two decades, the biggest issue for shark conservation was the practice of finning. In Asian cuisine, fins are highly prized as the main constituent of shark fin soup.
In 2006, it was estimated that between 26 and 73 million sharks were being killed for their fins every year. To try and reduce exploitation levels, authorities (the EU, for example) began requiring that fishing vessels must land the entire shark carcass and not just take the fins. The idea was it would reduce how many sharks in total were taken because the whole bodies would take up more room on boats.
But this may have had unintended consequences, says Ryburn. “It has created a market for shark meat,” she says. Not only that, but shark meat smells of urea and requires a lot of preparation for it to be edible and – as a result – is sold quite cheaply. “It’s become a cheap way for people to buy meat,” she adds. And that means many shark species – the oceanic equivalent of lions or tigers – are becoming even more endangered.
Top image: shark steaks being sold at a US grocery store. Credit: Savannah Ryburn
More wildlife stories from around the world
- In 2020, humans suddenly vanished from a popular bay in Hawai‘i. What happened next was remarkable
- Panama’s ocean upwelling fails for the first time in 40 years. Now scientists are worried
- Wildfires, ruptured cells and hot rivers: What happens when there’s no rain in a rainforest?
- Scientists spent 6 years tracking Yellowstone's great bison migration. What they found is remarkable
