THE “SHARKSAFE” SHARK BARRIER
Taking the plunge
Karridene is a resort town about 30 km south of the city Durban of South Africa. Here the Indian ocean is warm and pleasant to swim in. On 18 December 1957, Robert Wherley was 16 years old and a very active sportsman. He was a member of the local lifeguard club, and enjoying himself at the beach. At about 4.30 pm in the afternoon he decided to go and bodysurf the waves. The best waves were just south of the normal bathing area, and this is where he went. He was about 50 metres off shore when he saw a dark shadow in the water. It was moving towards him fast. It was a shark, and there was nothing he could do. He felt a huge shock and the shark was shaking him by the leg and then bit clean through his leg. The next moment he was free, and he managed to catch a wave half way to the beach. People on the beach pulled him out of the water. With shock and horror hundreds of beachgoers saw a young man with his leg bitten completely off just below the knee. Fortunately competent help was available right at the beach,and for the first few days the young man's life was hanging in a balance and with excellent medical treatment he managed to pull though. The real horror was still to come.
Kreslí Čuma, píše Avalpán
Two days later the 15 year old Allan Green was swimming at Uvongo beach 100 km south of Karridene. He was standing on a shallow sandbank about 30 metres from the beach when a huge shark bit him on the upper body. He never had a chance. Brave holidaymakers on the beach managed to retrieve his body, when they got him to the beach it was too late. December is peak holiday season in South Africa, and once again hundreds of holidaymakers were on the beach and saw the attack. Three days later the 23 year old Vernon Berry was swimming at Margate, a very popular beach near Uvongo. His friends hear him shout and saw him tumbling in the water in the jaws of a huge shark. The shark then let go and his two friends went to help him, his left arm was bitten off and his right arm was stripped of flesh, he had huge bites in his buttocks and his right thigh. He had lost a great deal of blood and passed out as his friends got him to the beach. He died on his way to the hospital. In the next week or so 4 more attacks took place on this part of the coastline south of Durban. While the first attack was small news, the panic grew as newspaper headline after headline followed. The public went hysterical, resort owners and hoteliers could not believe how thousands of holidaymakers simply packed their cars and left for home.
The public demanded answers. Local Municipalities started erecting fence like enclosures at the beaches to protect the bathers. The navy even sent a ship the “Vrystaat” to depth charge the waters around Margate. All to no avail, the fences washed away, and the depth charges killed lots of fish, but no sharks. Unlike fish, sharks do not have air bladders, so the fish died but not the sharks. All the dead fish was now shark bait. December 1957 is known as “Black December” in South Africa. There is a huge emotional aspect connected to shark attack. Hundreds of people die on South African roads in every December, but almost nobody is scared of driving and road accidents are almost shrugged off. Not so with shark attacks, and bear in mind that 1957 was long before the film “Jaws” ( 1975) scared people out of their wits and some even out of their plunge pools. The South Coast holiday industry depends on holidaymakers visiting, so it was clear that something had to be done to make swimmers feels safe in the water. In 1964 the Natal Anti-Sharks Measures Board was formed with the task of protecting the beach going public from shark attack. Today the Natal Anti-Sharks Measures Board is simply known as the “Natal Sharks Board”, NSB in short. Since 1964 they have been using “shark nets” to catch as many sharks as possible at the beaches they were protecting. It is a system of gill nets anchored in water of about 10 metres deep.
The function of these nets are too catch sharks, but they do not only catch sharks. They catch turtles, dolphins, rays and even whales. Most of these animals die. They also catch hundreds of sharks, most of which are harmless. The Shark nets are very effective in preventing shark attack. Simply because they are such good extermination devices. It is clear that the ecological impact of the nets are unsustainable and that it is time to replace them with a system that does not kill the sharks and larger ocean life.
NEW SHARK BARRIER
This has been a hot topic of discussion for many years especially in the diving and conservation community. Every time that the South African government is challenged on this issue, the response is:”yes, true, but what is your alternative?” There had to be some viable alternative. Every keen recreational diver in the Western Cape feels a lot safer in the big kelp forests because they never encounter Great White Sharks in the kelp forests. So if you are snorkelling for crayfish or spearing some fish, then you like to be in the kelp. No shark worries there. Mike Rutzen started thinking about this and got an idea to make an artificial barrier system that looks like kelp, and then test it. In the meantime a researcher in the USA, Dr Craig O'Connell, was experimenting with the effects of magnetic fields on several species of warm water sharks like Bull ( Zambezi) sharks, Tiger sharks and others. Dr O'Connell's tests in the Bahamas yielded good results, but he needed to include white sharks in the tests, so he contacted Mike Rutzen to help, and testing in South Africa started. The first issue was the question of practical deployment of the magnets. Mike had the answer, combine the magnets in the artificial kelp barrier system. At this stage the University of Stellenbosch became involved to guide and assist with the development of the system.
The barrier system consists out of thick plastic pipes anchored on the ocean floor. It is deployed in several parallel rows to resemble a kelp forest. The magnets are places inside the pipes. This creates a visual obstacle and the magnets inside the pipes create a magnetic field that repels the sharks. The year 2014 will be the third year of testing. Testing in the previous 2 years yielded positive results, and many improvements to the design could be made.
This new barrier system is called “Sharksafe” because it does not harm sharks, dolphins, turtles or any other sea life. It requires less maintenance than the shark nets, and is a lot more cost effective in the long term. Once the 2014 tests are concluded, a test beach will be selected, and the system will be deployed at a beach as the final phase of testing.