The incident on Friday, which occurred near the Starfish Hotel in Courland Bay, prompted the government to shut seven beaches and a marine park along the northwestern coast of the Caribbean island.

The shark appeared to be a bull shark, according to the Tobago House of Assembly, and was 8-10ft long and 2ft wide.

Chief Secretary Farley Augustine said the victim was a 64-year-old British man, adding he was in a "stable" condition but had suffered severe injuries to his arm, thigh and stomach.

A local official named him as Peter Smith, from Berkhamsted in Hertfordshire.

"Some reattachments were done, of fingers for example, and hopefully that will save those fingers," Mr Augustine said in a news conference.

"We know that there's significant wounds on one of his legs that cannot be completely closed, but he will require extensive work.

"The task at this time for our health professionals is really to stabilise and ensure that we can save life and limb as much as possible."

A $10,000 (£8,000) bounty was initially offered to anyone who could capture the shark, but this was later retracted.

A watersports manager at a beach hotel who saw the incident said the man was about waist deep in the water when the shark attacked.

He told local media their backs were turned, and they did not see the shark approaching.

"The other people in the water were physically trying to fight the shark off while it attacked," he added.

In a statement, the government said shark sightings were reported in the Grafton area and the Buccoo Reef Marine Park.

Officials said the closures will allow the coastguard and Department of Fisheries to investigate the incident and "neutralise the shark threat, if possible".

A Foreign Office spokesperson said: "We are supporting the family of an injured British man in Tobago and are in contact with the local authorities."

Last year, there were 69 unprovoked attacks and 22 provoked bites worldwide, along with 14 fatalities, according to the Florida-based International Shark Attack File.