A record 28.7 tonnes of illegally fished shark fins have been confiscated from two export companies in Brazil.

Brazil's environmental protection agency, Ibama, estimated that approximately 11,000 blue sharks and shortfin mako sharks were killed to make up a haul of that size.

The fins were destined for Asia, where shark fin soup is considered a delicacy.

The two companies have not been named.

Almost all of the shark fins - 27.6 tonnes out of the total of 28.7 - were seized from a single export company in Brazil's southern Santa Catarina state.

Ibama confiscated the remaining 1.1 tonnes at São Paulo's international airport.

The agency said it thought it could be the largest seizure by weight of illegally fished shark fins worldwide so far.

Fishing for sharks is illegal in Brazil. Ibama said that the companies were using permits for fishing different species and then illegally targeted sharks.

The agency also accused the companies of having caused the death of thousands of seabirds during their shark fishing expeditions.

The two companies have been fined.

Ibama warned that illegal fishing has caused the shark population to drop. The shortfin make shark was added to Brazil's list of species at risk of extinction just three weeks ago.