REPORTS of a man-eating shark lurking in the waters off St Ives have caused a stir in the holiday resort this week.

Two fishermen claim to have seen an oceanic whitetip shark, said to be the most dangerous of its species, a mile off Porthmeor Beach. One said he spotted a mottled white-tipped fin zig-zagging towards him before the shark's head came out of the water and it rammed into the side of the boat.

The 60-year-old fisherman, who has been fishing in St Ives Bay all his life, described the moment he first saw the creature.

"I was interested so I stood up to have a good look at it. As I was looking over the side of the boat, it just slammed into it," he said. "Then its head came out of the water by about a foot. It was that close to the boat that it slammed the side with its body and tail. It came as a bit of a shock. It was aggressive and we don't tend to have aggressive sharks in these waters."

Moments later two fishermen on board a second boat said they were circled by the shark. One described the distinctive white tips of the dorsal and lower pectoral fins, adding: "The water was crystal clear and we had a perfect view. It was pretty scary when you think about it."

But St Ives harbourmaster Stephen Bassett, who was informed of the double sighting two weeks ago and has received no sightings since, said the evidence was limited. He said it was possible but unlikely the shark was in such shallow water.

"As soon as I was informed I reported it to the relevant authority but since then I have not seen or heard any evidence to suggest the shark is out there," he said.

Experts are investigating the claims. If confirmed, they would be the first time the creature – responsible for more human deaths than all other shark species combined – had strayed into British waters. The reported sightings have grabbed national media attention, with headlines proclaiming the advent of 'Jaws Terror' and 'Cornish Nasty'. But despite the frenzy surrounding the reported sightings, holidaymakers and local businesses were not taken aback by the reports. "No one takes it too seriously," said Harris Rothschild from St Ives Surf School.

"We reckon between all of our instructors we have over 40 years of surf experience and none of us have even seen one let alone been attacked by one."

The mayor of St Ives, Ron Tulley, said that "panic hasn't struck and all is peaceful and very calm in St Ives", despite the reports.

Chairman of Visit Cornwall Malcolm Bell explained the media reports weren't far off having a negative impact on tourism.

"I think tourists need to remember that statistically they are more likely to fall out of the air in a plane than they are to be killed by a shark," he said.

Richard Peirce, chairman of The Shark Trust, said more work was needed to confirm whether the 7ft shark was an oceanic whitetip.

"It is always exciting and interesting to get sighting reports of what may be new species in our waters," he said.

"Elements of the description we have heard are consistent with oceanic whitetips but to date there are no confirmed reports of oceanics in UK waters, which are outside the temperature range usually tolerated by this species."

A year ago, Hayle fisherman Mike Webb told The Cornishman how he was reeling in a pollock when a thresher shark grabbed his fish before disappearing into the waves.