The case of 30 hammerhead sharks that died in a French aquarium after being captured on the Great Barrier Reef has sparked calls for the species to be banned from live export.

The scalloped hammerheads were exported to Europe’s biggest aquarium, the Nausicaa aquarium, near Calais, from 2011 to 2018.

Conservation group Sea Shepherd France has now launched legal action against the aquarium after the last shark died two weeks ago.

Thirty hammerhead sharks died in captivity at the Nausicaa aquarium, near Calais, over an eight year period. (AAP)

Nausicaa said their deaths were caused by a fungal infection but Sea Shepherd France claims some of them attacked and ate each other. It says the animals were mistreated in captivity.

The sharks were sent to Europe by a Queensland company that supplies ocean life to aquariums - after they were caught in an approved fishery area around the Great Barrier Reef.

Australian government scientists have identified the scalloped hammerhead as being suitable for an endangered listing. But the species is currently classified as “conservation dependent”, a category that allows threatened marine life to be fished.

Conservation groups say the case highlights the need for the species to be better protected.

Leonardo Guida, a shark expert at the Australian Marine Conservation Society (AMCS), told nine.com.au he was “gobsmacked” the sharks could be exported live.

There has been a major decline in hammerhead shark numbers on the Great Barrier Reef, experts say. (AAP)

“There has been an 84 per cent decline in scalloped hammerhead numbers in Queensland waters,” he said.

“I was gobsmacked to learn 30 have died on the other side of the world when they should be on the reef.”

Dr Guida said hammerhead sharks become extremely stressed when captured, often leading to exhaustion and death.

Humane Society International Australia (HSIA) has been campaigning for the scalloped hammerhead to be granted an endangered listing since 2010.

Along with the AMCS, it plans to appeal again for the species to receive this category.

Hammerhead sharks play an important role in maintaining the health of the Great Barrier Reef. (AAP)

Nicola Beynon, the group’s head of campaigns, told nine.com.au, there are no conservation benefits in exporting sharks from Australian waters to overseas.

“The scalloped hammerhead qualified for protection as endangered but it doesn’t receive it because it’s commercially exploited. If it was a land animal like a koala, that would never occur.”

Ms Beynon said hammerhead sharks are an sensitive species that become extremely stressed in captivity.