Sharks play crucial roles in marine ecosystems. As predators, they loom large at the top of many marine food chains and help maintain a certain balance.
Unfortunately, many shark species are declining in numbers, with many of them endangered or at risk of endangerment, threatening ecosystems. There are many reasons for these declines (such as climate change and loss of habitat) though overfishing of sharks, in particular, has caused a significant decrease in shark populations. Shark byproducts are used for a range of purposes, including meat and even beauty cosmetics (though all plants and animals make it, an oil called squalene is derived from sharks for many cosmetic products).
To make matters worse, it turns out the meat of endangered sharks could be showing up in your pet’s food.
Published in Frontiers in Marine Science, researchers outline efforts to understand to what extent shark byproducts are found in pet foods sold in Asian markets. Researchers cite a previous study conducted in the U.S. that had similar goals, and found the presence of sharks in 78 different pet food products.
Researchers looked at 144 different samples of pet food products sold in Singapore to look for traces of shark by product. Researchers found that almost a third of sampled products contained shark byproducts, with the most prominent species including the blue shark and whitetip reef shark, both of which are listed as vulnerable species.
DNA barcoding was used to look for shark DNA in pet food products. DNA barcoding is a way of making species-level identifications. Barcoding usually uses a particular section of a DNA sequence from a genome to make these identifications. In addition to helping monitor species, barcoding can also be used for a range of other conservation tasks as well agriculture, for example.
But “shark” doesn’t show up on a food label; you might see a vague term like “ocean fish” or “white fish,” instead. That’s why the study authors urge for greater transparency in food labeling to help call attention to the overfishing of endangered shark species and help regulate fishing activities.
Sources: EurekaAlert!; Frontiers in Marine Science; Nature