A German tourist has died after a shark bit off her leg in the Atlantic south of the Canary Islands.

Spanish authorities dispatched an air force helicopter to rescue the woman but she died while on board the aircraft as it headed northward towards one of the archipelago’s hospitals.

The woman, 30, who has not been named, was on a cruise on a British-registered pleasure boat, when the attack happened shortly before 4pm on Monday afternoon.

It has not been reported how the attack took place, but shark-related incidents off the coast of north-west Africa and near the Canary Islands are extremely rare.

The crew of the Dalliance Chichester catamaran reported the emergency at 3.55pm on Monday to Spain’s coastguard. At the time the vessel was situated about 300 miles south of Las Palmas de Gran Canaria, and just over 100 miles from Dakhla, a city in Western Sahara, a former Spanish colony over which Morocco claims to have sovereignty.

Spain’s coastguard asked Morocco if its rescue services were available to offer assistance but the Moroccan coastguard said it did not have resources in the area.

The Spanish coastguard also issued an alert to all shipping in the area near the catamaran, with one vessel responding by taking medical supplies to the Dalliance Chichester.

Authorities in the Canary Islands decided to scramble a Spanish Air Force search-and-rescue helicopter, with a military plane supporting the mission.

The helicopter came from Gran Canaria to help the injured woman, taking her aboard at around 8:05pm. The woman, who had had one of her legs severed by the shark, was still alive when she was winched on board the aircraft some four hours after the attack. But she reportedly suffered a fatal cardiac arrest during the rescue flight.

The body of the victim was taken to the Doctor Negrín hospital in Las Palmas de Gran Canaria, where she was declared dead.

According to online maritime traffic monitoring navigators, the Dalliance Chichester had left Las Palmas de Gran Canaria’s port last Saturday and headed south.

The International Shark Attack File, compiled by the Florida Museum of Natural History, said Monday’s attack was the first confirmed incident involving a shark in waters near the Canary Islands that resulted in death.

The file mentions six confirmed incidents in the area, with a seventh incident considered probable.

No shark incident had previously been documented in the area where Monday’s attack took place. The closest, apart from those in the Canary Islands, was reported in the African archipelago of Cape Verde.