Nature Shock : The Blacktip Shark Mystery

In spring 2006, dive boat operator Mark Addison witnessed the mysterious arrival of sixty Blacktip sharks on the Aliwal Shoal off the coast of South Africa.  Blacktips were not unknown on this reef but such numbers were unprecedented.   At first it was thought the sharks’ arrival coincided with the annual sardine run, when millions of fish pass up the coast.  But this theory was blown out of the water when something even stranger happened – the highly migratory Blacktips stayed put.

The shark gang took over the reef, chasing off the much larger tiger sharks that are the focus of Mark’s dive boat operation. His business under threat, he decided to turn detective.  He discovered the gang was 100% female and was actually almost two hundred strong.   Over time he came to believe that not only did the gang have a hierarchy and a pack leader but they were also communicating with each other from a distance.   His theories could rewrite science.

Meanwhile local fishermen were being mugged for their night-time catch. Salmon were being torn apart before they could be landed.  Many blamed the Blacktip bandits and their fears were confirmed when a few sharks began harassing spear-fishermen in broad daylight, stealing their catches too. Concern grew that such a cocky gang of sharks were operating just off the coast.

And it appeared they were learning .   Mark suspected that they were following boats in search of food.  With the sharks becoming more of a menace, he decided to launch an experiment to find out if he could solve the mystery.   Would his research confirm these smart sharks were getting smarter? And would it provide an answer as to why the Blacktips had remained at Aliwal?