Parts of the idyllic Blue Lagoon turned red yesterday as a dying four-metre shark drifted upside down with blood flowing from its gills, much to the surprise of a family of sailing enthusiasts anchored at Comino who captured it on film.

Nancy Hancock and her husband, both charter skippers who sailed to Malta from Canada in September 2009, were alerted to the shark by two local men with diving equipment on a dinghy who had towed the fish closer to shore.

They immediately scrambled aboard their own dinghy for a closer look and were shocked by its size.

“It was as big as the dinghy and had teeth about an inch-and-a-half (3.8cm) long, but it was clearly dying. We thought it might have ingested something poisonous since it was bloated and had blood seeping from its gills,” Ms Hancock told The Sunday Times.

Despite spending a lot of time sailing, Ms Hancock had never seen a large shark around the Maltese islands before and neither had her husband or the men on the other dinghy.

After taking photos and video footage, they left the shark and did not alert the authorities, since it was clearly no threat.

The Sunday Times showed the photos and video footage to local shark expert Alex Buttigieg, known as ‘The Sharkman’, who said that although he could not be certain because the gills, teeth and the dorsal fin were not clearly visible, it seemed to be a harmless Bluntnose Sixgill shark (Hexanchus griseus), a deepwater species which can grow up to 5 metres in length.

Mr Buttigieg stressed there is certainly no cause for alarm.

“The fact that it had blood coming out of its gills could indicate that it was caught and dumped by fishermen,” he added.

Greg Nowell from Sharklab and marine biologist Alan Deidun agreed that it seemed to be a Bluntnose Sixgill.