Great White sharks in the Mediterranean

It is a little-known fact that Great White sharks can be found in the Mediterranean Sea, and perhaps even less-well known is that they arrived there some 450,000 years ago from Australia, according to new genetic studies.

According to a BBC article published today:

“Researchers writing in Proceedings of the Royal Society B believe the arrival may have been simply a migratory ‘wrong turn’ by a few pregnant females.

A tumultuous climate between ice ages may have been the cause.

The species – Carcharodon carcharias – would have remained in the Med because it returns to spawn where it was born.

It was previously assumed that the great whites in the Mediterranean were most closely related to their nearby cousins in the Atlantic Ocean.

But now, a team led by Les Noble of the University of Aberdeen has examined the several groups of sharks’ mitochondrial DNA – genetic material passed through the maternal line that is particularly suited to tracing lineages.

The team found that the Mediterranean sharks were very different to the Atlantic group and more like sharks from Australia and New Zealand.”

Great White shark attacks in the Mediterranean

The great white shark is most commonly associated with the coasts of Australia, California and South Africa, but there have been occasions when this increasingly rare animal has been spotted in the Mediterranean. Some experts believe that the Mediterranean is a nursery where great white sharks give birth and raise their young. The Sicilian channel, near the Italian island of Lampedusa, is the only location in the Atlantic region where both pregnant females and newly born great whites have been sighted.

A great white shark was caught in Malta by Alfredo Cutajar in April 16, 1987. This shark was also estimated to be around 7.13 m (24 ft).

The map below shows confirmed sightings of great white of great white sharks in the mediterranean sea since the early 20th century:

Mediterranean Hammerhead shark population fallen by 99.99%

Conservationists have examined historical fishing records which show that sharks in the Mediterranean Sea have suffered dramatic declines in the past few decades due to overfishing.

The scalloped hammerhead shark. A team of scientists at Dalhousie University in Nova Scotia, Canada, examined fishery logbooks that chart the demise of several shark species. The records show hammerheads all but vanished from coastal waters in 1900, and have barely been spotted in the open sea for 20 years. They say the hammerhead population has fallen 99.99% in 200 years.

Some thresher shark species have dwindled by more than 99%, according to the fishing records examined by conservationists.

Records from long-line fisheries suggest a 99.99% fall in mackerel sharks. The typical size of sharks caught in the Mediterranean is among the lowest in the world, indicating that more young sharks are being caught.

Since the mid-1950s blue sharks have declined by 96.5%.

Conservation groups fear that without strict catch limits on sharks, many of the 47 species in the Mediterranean will soon become locally extinct.

From the Guardian.co.uk: See slideshow story