The crew of the Vanguard creel boat were out fishing for lobsters and crabs off the coast of Fife in the Forth when they realised they had snagged something “heavy”.
On pulling in the gear they were surprised to come face to face with an 8ft porbeagle shark, which was “very much alive, and not impressed”.
The men, skipper Nick Irvine and crewmates Rodger Watson and Josh Kelner, were lucky to dodge the angry beast’s snapping jaws as it writhed and thrashed in an effort to get free.
Luckily they were able to cut the ropes entangled around the shark’s tail and release it back into the sea unharmed.
Mr Watson said: “We were pulling up the pots and when we got to the keel end rope the gear suddenly became heavy.
“We must have just caught the shark.
“We pulled in the rope and discovered it was tangled around the shark’s tail.
“The shark was very much alive, and not impressed.
“It must have been 7ft or 8ft long and it tried to get a bite at us.
“We pulled it up to the side of the boat, lifted its tail and cut the rope. It quickly swam off.”
It was at first thought the creature was a blue shark but was later identified as a porbeagle, both of which are not commonly seen in the Forth.
The porbeagle belongs to the same family as the great white shark, made famous in the cult thriller Jaws.
It is a powerful and agile predator that can grow to more than 10ft in length and has around 27 rows of jagged teeth in each jaw.
It is not considered a danger to humans, existing on fish such as mackerel and herring – hence it is also known as a mackerel shark.
There have been few reports of attacks, none fatal, with most bites inflicted on fishermen after being landed on a boat.
The species is also known to be curious and has often been recorded approaching divers carrying out maintenance on oil rigs.
Its conservation status is listed as vulnerable.
Shark sightings in the Firth of Forth are uncommon, but they do happen.
The video of the shark was posted on the Fish of the Firth of Forth Facebook site.
Local fisherman and founding member of the group Martin Rowan says there have been a number of interesting sea creatures spotted in the area in recent years.
“Since the group was formed there has been a surprising amount of sharks and other unusual fish reported in the Firth of Forth,” he said.
“So far we have tope, porbeagle, blue shark and basking shark – all totally non-threatening to humans.
“Thankfully the people in the video supplied by Rodger Watson managed to free the shark from the rope.
“It’s great to see people do this.
“Any shark caught should always be released alive.”
He also urged anyone who comes across unusual species in the area to report it on the Fish of the Firth of Forth page.