Separating the killers from the kids

Durban's Golden Mile in South Africa is a shark hotspot where swimmers equal lunch, but as one reporter finds, prevention is not always better than cure.

Etched into the grey predawn horizon, a small yellow boat weighted with shark nets bounces through the sub-tropical surf of Durban's Golden Mile.
Aboard is a crew of five men dressed in slick orange oilskins.

They are from the Natal Sharks Board and their job is to maintain the 17 shark nets that zig-zag along the coastline.

With its engines off, the boat rises and falls with the large ocean swells.

It is quiet except for the slapping of the net in the water.

The men in the boat pull themselves along the raised shark net, checking for damage.

These shark nets have reduced over 90 per cent of fatal shark attacks at protected beaches on the Kwa-Zulu Natal coastline.

The Natal Sharks Board (NBS) was formed as a result of 1957's "Black December" when there were five fatal shark attacks and something had to be done to entice the tourists back onto the beaches.

Today, anchored just past the bathing area, the nets do not stretch down to the seabed, but only some 20 feet down in the 45 feet deep water.

"The shark nets are not barriers preventing sharks from coming into the shoreline," says Craig Charter, a visitor's guide with the NSB.

"They are fishing nets, designed to catch sharks that encroach on human bathing areas."

The dawn sun has broken the horizon.

As it brightens the crew continue to mesh, toiling with the wet weight of the net.

This morning it is heavier than usual. A black-tipped shark has been caught.

It had entwined itself so tightly in the netting that it suffocated.

Sharks breathe by swimming with their mouths open, taking in water and oxygen, which then passes out through the gills.

Sharks caught in the nets become restricted and panic. Thrashing about, they become more entwined and it takes two hours for them to suffocate.

The men heave the shark into the boat. They haven¹t reached this one in time.

They cut the meshing to release the dead weight of the shark and replace the net with a new one.

"Contrary to belief, most sharks get caught on the shoreline side of the nets," says Craig.

"At dusk they come in to shore to feed by swimming in low underneath the nets. At dawn, when the sunlight glints brightly off the shallow waters, sharks with their sensitive eyesight head out to the darker, deeper offshore waters, forgetting about the nets sitting between them and the deep blue sea."

This is the reason the NSB go out net-checking at dawn, to free any entangled sharks before they asphyxiate.

These nets are not without controversy.

If sharks get caught in the nets, so then do other marine creatures of the same size, dolphins and turtles being particularly vulnerable.

A small white cylindrical battery-operated device called a "pinger" is attached to each net. It emits intermittent low frequency electronic pulses, repelling dolphins away from the nets.

Environmentalists, however, are concerned that pingers cause noise pollution in the sea.

The frequency emitted, although low to human hearing, could be loud and stressful to marine life. It is a vicious circle for the NSB where the equation of human safety versus marine conservation hangs in the balance.

Although seen as a pollutant, electrical currents could replace meshed nets as predator repellent, thereby reducing marine casualties.

As well as an acute sense of smell the shark's snout is highly sensitive to low electrical pulses from overly large distances.

An electrical shark repellent for scuba divers, the SharkPOD (Protective Oceanic Device) is already in use.

And further research is being done to create miniature electrical repellents for those most vulnerable to shark attacks: bathers, surfers and attachments for life jackets.

Back at base, with the morning sun already high in the sky, the meshing crew offload the nets and clean the boats, ready for the following day.

A heave-ho chant begins as three men pull the wet heavy nets from the boat. The nets are then spread out on the ground and the meshes thoroughly checked and repaired.

The red blood of the black-tipped shark found in the nets this morning stains the side of the boat.

Its smooth grey hide exudes a pungent wild marine smell and its eyes stare listlessly at the sky as it is loaded into a truck to be taken to the NSB visitors centre.

Here scientific research will determine its sex, age and weight before the shark carcass is refrigerated.

It will be used for public dissection lectures which teach visitors more about shark physiology, offering them a glimpse into the life of this ancient marine predator.