Thursday, November 18, 2010

Australia's Great White Sharks- Accidental Migrants in the Mediterranean

Great white shark

Konyaalti Beach in Turkey; one of the possible locations of shark findings

A study recently showed that Australia's great white sharks had accidentally ended up along the Mediterranean after making a wrong turn on their migration routes back to the Aussie waters. Four sharks had been sighted in recent years off the coasts of SicilyTunisia, and Turkey. Interestingly, they all share the same DNA as their relatives Down Under. According to scientists, the ancestors of these predatory fist had found themselves near Mediterranean's coastline after making a navigational error. Fortunately, the later generation of these sharks turned out to be in low numbers. This is because white sharks return to their birthplace in the same way as salmon. Two years ago, two of these four sharks were captured in the Bay of Edremit in Turkey. The third one was sighted off the coast of Tunisia in 2006, and the fourth was found off Sicily twenty years ago.

Scientists believe that the original journey was made 450,000 years ago by a few pregnant female sharks. During this journey, the females probably had taken a wrong turn due to climate change, high sea levels, and some unusual ocean eddy currents known as Agulhas rings. Usually, the warm Agulhas Current flows down Africa's east coast. But sometimes an Agulhas ring carries its waters around the dark continent's southern tip, and into the Benguela Current off South Africa's west coast. The pregnant female sharks may have been led astray by the current due to severe climate change at that time, and continued to head west instead of east towards Australia. Once they reached the Atlantic Ocean, they were free from the currents and turned around and in turn ended up in the Mediterranean. According to Dr. Cathy Jones, a shark geneticist from the University of Aberdeen's School of Biological Sciences, once the sharks entered the mouth of the Mediterranean, they were trapped because the region's channels and peninsulas make it seem like a giant lobster trap. It has also been thought that the sharks' prey, which in this case the swordfish and bluefin tuna, had arrived to the region the same way as the predators.

This article, in my opinion, really defines one of the greatest phenomenons that had occurred on Earth over the period of time. In this case, it goes to show how great white sharks originally situated off Australia's coast had made their way up into the Mediterranean region due to climate change at the time. As a result, they have ended up flourishing in the region becoming an apex species. Thankfully for Mediterranean's inhabitants, the current generation of these sharks in small numbers. But over the period of time, Mediterranean's great white shark population will increase and may lead to numbers of attacks just like in Australia and South Africa. I sure hope that these sharks will receive some protection such that both they and Mediterranean people will be safe from each other.

View article here           

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