We’ve had whales, we’ve had walruses as well as hundreds of dolphins but the latest sighting of a massive shark’s fin has prompted a warning to stay out of the water.

No idea where the mayor of Porthleven was, but his insight may have been necessary as the large shark’s fin was pictured just 20 to 30 metres off of Gunwalloe Beach near the Halzephron pub yesterday afternoon.

Falmouth Packet: Cropped image of the shark fin pictured off Gunwalloe Beach, CornwallCropped image of the shark fin pictured off Gunwalloe Beach, Cornwall (Image: Jacquie Williams)

There has been speculation as to what type of shark it could be including a Great White or a Porbeagle.

The picture was taken at around 10.30am by Jacquie Williams who has lived in Cornwall all her life and owns a boat and said it definitely wasn’t a basking shark as it only had one dorsal fin. 

Her son in law Gazza Laidlaw posted the picture on the Porthleven Facebook today with a tongue in cheek call for people to stay out of the water.

“Hi everyone, this shark was spotted at the other end of the beach at Gunwalloe this afternoon by my mrs's mum, so any winter swimmers might want to proceed with extreme caution as it looks rather large."

The post prompted a wave of comments with some people questioning whether the photo was photo-shopped, but Gazza says it is 100% genuine.

He told the Packet: “It sparked my interest because she said there were herring all over that area of the beach.

“Being a keen angler I assume it was feeding on bait-balls of fish and they were beaching themselves trying to flee it.

Falmouth Packet: The shark fin pictured off Gunwalloe Beach by Jacquie Williams The shark fin pictured off Gunwalloe Beach by Jacquie Williams (Image: Jacquie Williams)

“I know a lot of people don’t believe the water temperatures have changed and can be home to more exotic species of marine life but it was only last year a great white was spotted off the Cornish coast, so we can only guess what this shark might be.

“I don't want to speculate too much but that fin looks rather ominous to me, hence the warning on the Porthleven page.”

This time last year a possible white shark fin was spotted off the beach at Goring-by-Sea, near Worthing, West Sussex.

Experts say climate change could mean Great White Sharks heading up from the Mediterranean where they already are as waters warm.