Great white sharks in the Mediterranean Sea are in danger of disappearing, with illegal fishing contributing to their decline.

This is according to research by US scientists, working in partnership with UK charity Blue Marine Foundation. They say some of the most threatened species – including great white sharks – are being sold in North African fish markets.

Great whites are one of more than 20 Mediterranean shark species protected under international law, meaning it is illegal to fish for them or to sell them.

By monitoring fishing ports on the Mediterranean coast of North Africa, however, researchers discovered that at least 40 great white sharks have been killed there in 2025 alone.

The BBC has also found, and independently verified, footage from social media of protected sharks being brought dead into North African ports.

One video showed a large great white being hauled ashore from a fishing boat in Algeria. Another, filmed in Tunisia, shows heads and fins of what appears to be a short-finned mako shark, which is also a threatened and protected species, being prepared for sale.

Lead researcher, Dr Francesco Ferretti from the US university Virginia Tech, explained that many shark populations – white sharks in particular – had declined dramatically in the Mediterranean in recent decades.

“No other stretch of water is fished like the Mediterranean Sea,” he said, speaking to the BBC News science team while working on a research vessel off the coast of Sicily in late 2025.

“The impact of industrial fishing has been intensifying… and it’s plausible that they will go extinct in the near future.”

The Mediterranean white shark population is now classified as Critically Endangered by the International Union for the Conservation of Nature.

In their latest attempt to find and study the predators, Dr Ferretti and his team worked in the Strait of Sicily – an area between Sicily and North Africa that has been identified as a “last stronghold” in the Mediterranean for several threatened shark species.

One key aim of their mission was to fit a satellite tracking tag onto a white shark – something that has never been done in the Mediterranean Sea.

To attempt this, the researchers brought more than three tonnes of fish bait – a shipping container packed with frozen mackerel and tuna scraps, as well as 500 litres of tuna oil to create a “fat slick” that many sharks would be able to smell from hundreds of metres away.

Despite working for two weeks – baiting the ocean, taking samples of seawater to search for shark DNA and using underwater cameras – the researchers did not manage to find any animals to tag.

They captured only a brief glimpse of one blue shark on their submarine cameras.

“It’s disheartening,” Dr Ferretti told us. “It just shows how degraded this ecosystem is.”

While the team was searching for surviving sharks, they also received reports that a juvenile great white had been caught and killed in a North African fishery – just 20 nautical miles from where they were working.

It is not clear whether that animal was accidentally caught in fishing gear, or if it was targeted.

Dr Ferretti and his team, though, estimate that more than 40 great white sharks have been caught around that coast. “This is a lot for a critically endangered population,” he said.

The researchers, with their colleagues in North Africa are monitoring several fishing ports in the region. Our work, with the BBC Forensics team, also shows that protected sharks are caught, landed and offered for sale in countries including Tunisia and Algeria.

We found footage – posted on social media – of a great white being landed in a fishing port in Algeria and another large shark that appears to be a protected short-finned mako, being prepared for sale on a trolly in a fish market in Tunisia.

The rules that protect sharks are complicated. Currently, 24 threatened species have international legal protection – including mako, angel, threshers and hammerheads.

The EU and 23 nations around the Mediterranean have signed an agreement, which states that those species cannot be “retained on board, transhipped, landed, transferred, stored, sold or displayed or offered for sale”.

The international agreement states “they must be released unharmed and alive [where] possible”. Those rules do not tackle accidental bycatch and enforcement is variable from country to country.

James Glancy from Blue Marine told BBC News that his own investigation found multiple white sharks on sale in Tunisian fishing markets. But, he said, there was a paradoxical element of hope in the fact that white sharks were turning up for sale.

“It shows that there is wildlife left,” he told BBC News. “And if we can preserve this, there is a chance of recovery.”

In poorer communities in North Africa, fishers who catch sharks might face the choice of whether to feed their family, or return a threatened species to the ocean.

Sara Almabruk from the Libyan Marine Biology Society says that most of the catches happening in North African waters are accidental, but adds: “Why would they throw sharks back into the sea when they need food for their children?

“If you support them and train them in more sustainable fishing, they will not catch white sharks – or any sharks.”

James Glancy from Blue Marine added that if countries around the Mediterranean worked together, “there is hope.

“But, he added, “we’ve got to act very quickly”.