IN THIS WEEK'S ISSUE

Keeping great whites at bay

Talk of Durban's black December sends residents' memories reeling back to the darkest time of this otherwise pleasant seaside town.

  • Emmanuelle Landais, Staff Writer
  • Published: 00:00 November 20, 2009
  • Weekend Review

  • Image Credit: Supplied
  • Dead sharks that are not badly decomposed are brought into the laboratory, where they are weighed and measured. They are then frozen until they are dissected by technical staff, who record various biological data.

Blessed with dusty white beaches on South Africa's eastern coast means the shores dip directly into the Indian Ocean which record higher temperatures than the Western Cape.

These warmer seas means it's not only a pleasant place to swim but it also attracts a lot of marine wildlife. The kind that, despite their endangered species status are not always welcomed by bathers because of the fear they instill, based on fear-mongering stories and spurred on over the years by Steven Spielberg's cult movie, Jaws.

Sharks are largely blamed for single-handedly closing down the beach resort town in the 1960s due to 20 reported attacks. The Sharks Board was then created to ‘safeguard bathers against shark attacks'.

The Sharks Board manages all coastal areas of the Kwazulu Natal and service specifically 320km of beaches with shark nets to deter sharks from approaching the shoreline.

There is no other organisation like it in the world, says Mthokozisi Radebe, chief executive officer of Sharks Board which is directly affiliated with the Kwazulu Natal Tourism Board. "Seventy per cent of people who come to Durban come to the beaches. We need to do what we do to keep the people safe," he said. A budget of R17 million is spent annually to make it "safe to swim".

It all started in the 1940s. Between 1943 and 1951, 21 shark attacks took place and seven were fatal, and by 1952 seven gill nets, each 130 metres long, were laid along the Durban beachfront. In the first year of operation 552 sharks were caught in these nets, but more importantly, according to the Sharks Board, "the desired effect was achieved and no serious shark-inflicted injuries have occurred since at Durban's beaches."

Related Links

The nets helped but more attacks followed south of Durban, where a series of attacks between December 1957 — since known as the infamous Black December — and Easter 1958 claimed five lives in three months. Despite the huge environmental impact the nets have on local shark, dolphin, whale or turtle populations, the attacks had a devastating financial impact on the coastal tourism industry.

The Sharks Board carries out research based on the animals which get caught up and die in the nets every year. "An analysis of South African shark attack records over the last four decades has shown some interesting patterns. The results confirm that attacks are rare events, with an average of only six incidents per year," states the organisation's website.

In fact since 1990 only 26 per cent of attacks have resulted in serious injury and only 12 per cent were fatal. This equates to an average of one serious shark-inflicted injury every year and one shark-inflicted fatality every 1.6 years along some 2,000km of coastline from the Mozambique border to Table Bay in Cape Town.

Studies show that most attacks have taken place on swimmers in warm, shallow waters on Kwazulunatal beaches, but the shark nets have reduced the number of incidents in the province to less than 1 a year. The Sharks Board states that "there have been only two serious attacks at protected beaches in the last 25 years. Both involved surfers who were bitten in very clear water by a great white shark (Carcharodon carcharias). The last attack at a protected beach took place in 1999, which bears testimony to the success of the shark nets in reducing attacks."

The worst year on record in South Africa was 1998, when 15 attacks were recorded. All took place in Cape waters; one was fatal and a five resulted in serious injury. As the previous highest total was nine in 1994, there was much speculation in the media as to the reason for this marked increase.

The great white shark viewing industry was used as a scapegoat, as great whites were responsible for all six serious attacks in 1998. It was suggested that as the sharks were repeatedly exposed to bait used to attract them for cage divers, they now associated the boats and divers with possible food.

Mthokozisi Radebe, chief executive officer of the Sharks Board, is well aware of the stigma which surrounds the bycatch that is caught in the nets set out to protect people. "We try and co-exist with environmentalists. We remove the nets during the sardine season as well but we do need to do something to protect bathers otherwise we could lose thousands of Rand in tourism," he said.

Most of the shark nets deployed in the province are 214 metres long and 6 metres wide and are secured at each end by two 35kg anchors; all have a stretched mesh of 51cm. The nets are laid in two parallel rows approximately 400 metres offshore and in water depths of 10-14 metres. A drumline consists of a large, anchored float (originally a drum) from which a single baited hook is suspended. Durban has 17 nets, each 305 metres in length, which cover all the popular swimming beaches.

"The nets are hauled up every day from Monday to Friday and our team removes anything caught that has died and sets free anything still alive," said Radebe. "We caught a humpback whale once but managed to release it alive, after 5 hours, successfully."

According to Radebe, studies are being carried out on nets to see how big the mesh size could be to allow smaller fish to pass through unharmed and to minimise catching dolphins and sharks.

Once removed from the nets, any dead sharks or dolphins are taken back to the Sharks Board for study or dissection. It is quite common for visitors to the Board to witness a dissection which helps to increase awareness.

Caught, frozen or released

Every animal caught is identified, sexed, measured and recorded. Live sharks found in the nets are tagged and released but many are also injected with tetracycline to validate age and growth studies. Dead sharks that are not badly decomposed are brought into the laboratory, where they are weighed and measured. They are then frozen until they are dissected by technical staff, who record various biological data. A section of the vertebral column is removed for ageing studies and some jaws are kept for the Boards' reference collection. Additionally, various tissues are sampled for a variety of different studies.

By catch

Between 2004 and 2008 the average annual catch included 628 sharks (mainly of 14 species, 13.1 per cent released alive), 237 rays (mainly of seven species, 50.2 per cent released alive), 584 turtles (mainly of two species, 55.5 per cent released alive).

Weekend Review takes an in depth look at the issues behind the news

Weekend Review