Unknowingly, Brazilians are big consumers of shark meat. That is a problem

In the frozen fish aisle of most Brazilian supermarkets, amongst the tilapia and shrimp, it is common to find packages of a white fish labeled cação – which translates as dogfish in English. It is a cheap, boneless, and meaty fish, and is therefore quite widely eaten. But most Brazilians are unaware that the generically labeled “dogfish” is actually shark meat.

And its consumption is a threat to shark conservation and can even be harmful to humans.

The term cação refers to the dogfish, also known as the mud shark. But lax labeling requirements in Brazil mean that meat from any number of different shark and ray species can be sold as cação.

The consumption of shark is usually associated with China and other parts of Asia, where shark fin soup is a delicacy. The high market value of shark fins in these countries but lack of demand for the animal’s meat led to the widespread practice of finning — cutting off a shark’s fin for sale but returning the animal, sometimes still alive but mutilated, into the ocean.

The practice is now largely banned, meaning that fishermen have had to find a market for shark meat as well as the valuable fins. Brazil — which was one of the first countries in the world to outlaw finning in 1998 — has become such a market, despite not having a tradition of eating shark.  

“Shark has always been consumed in coastal and riverside areas, but it wasn’t such a big thing nationally,” says Bianca Rangel, a biologist researching sharks at the...