Shark attacks don't warrant increased cull - ABC News
Australia is not alone in having large sharks near populated beaches or for having a reputation for shark attacks.
South Africa is the world's hotspot for great white sharks. It is where documentary makers come to film the dramatic scenes of white sharks breaching in the chase for Cape fur seals and it is the centre of the great white shark cage diving tourism industry where, on a daily basis, fleets of boats head out of the tourism centres packed with people wanting to view a great white shark from the safety of a cage.
In terms of documented attacks, there were six in the period from 1951 to 1970, 25 incidents between 1981 and 1990, 23 incidents reported from 1991 to 2000, and 11 reported great white attacks in the first half of this decade.
In some years, there were anomalously high numbers of attacks, such as Black December in 1957 when five people were bitten by sharks south of Durban, or 1998 when a total of 18 attacks were recorded in South Africa.
The longer term trend of rising incidents since the 50s and 60s mirrors an increase in beach use but cannot explain the year-to-year variations. To date, science cannot conclusively say why there are higher numbers of shark incidents in some years compared to others. It is likely that an array of oceanographic, ecological or behavioural factors are to blame for bringing more or fewer sharks in contact with people in any particular year, but the specific causes remain unknown.
Already it looks like 2009 will go down in the record books as having an anomalously high number of shark attacks in Australia and in the Sydney region in particular. Just as with South Africa, more people in the water increases the chance of an interaction. A cleaner Sydney harbour also increases the chance of finding sharks as well as fish, but it is not clear what other biological, environmental or behavioural factors, if any, are adding to the high recent number of attacks.
There is no doubt that any shark attack is a terribly unfortunate and traumatic incident. Our sympathies are with the victims and their families. On a global scale, elephants, bees, crocodiles and lightning strikes kill more people each year than shark attacks, and beachgoers are at a far greater risk of death by drowning from rips or surf, yet the thought of being attacked by a shark remains a terrifying prospect.
Actions that can help ensure bather safety include increased investment in education and awareness program so that people understand basic rules. Some of these include avoid swimming alone, avoid being in the water when there are low light levels or reduced visibility, don't swim in waters with known effluents or sewage and stay away from fish or gull feeding areas.
Increased investment is needed in research and development, and testing of options such as observer programs, use of electromagnetic field technology and new shark repellent advances in concert with research into sharks, so that we understand more about the behaviour, ecology and environmental cues that affect these species. Together these will allow bather safety programs to be designed to be as targeted and effective as possible without also causing the deaths of marine creatures such as dolphins and turtles that also call the ocean home.
Of the more than 300 species of shark found in Australian waters, there are only a couple of species, most notably the great white shark and bull shark, that are recorded as attacking humans. The vast majority of sharks are shy elusive creatures that appear in a range of often bizarre shapes and sizes, patrolling reefs and open oceans where they fulfil a critically important role at the top of the food chain.
In terms of their reproduction, sharks are long-lived, slow growing and produce relatively few young, which gives them a population dynamic that is more similar to whales and dolphins than to fish. This makes shark populations vulnerable to over-fishing.
The history of shark fisheries the world over is one of 'boom and bust' where excessive fishing pressure causes populations to crash.
The result is that shark species are increasingly finding their way onto the lists of at-risk or endangered species, almost as quickly as new species are being described.
The high price being paid for shark fin in the Asian marketplace appears to be driving a gold rush type mentality around shark fisheries in Queensland and New South Wales. Opportunistic fishers push fisheries managers to increase shark catches and create new shark fishing licences, despite there being no scientific basis that such levels of take are within safe limits for the large numbers of species involved.
With sharks very much in the spotlight, cool heads need to prevail.
The calls for an increase to the shark fishing quota in NSW are driven by this opportunism. Some fishers are using the current media feeding frenzy around sharks to call for an increase in shark hunting levels and are making claims that have no scientific basis. They should be ignored.
Many of the sharks they already catch are docile creatures that are not involved in attacks on bathers. Some of the populations of shark species that these fishers pull out of the water for their fins and flesh are in steep decline.
This is not to deny that we need to find ways to ease the interaction between sharks and humans along our beaches. There needs to be an investment in education, awareness and research and development, so that bather safety programs can be as effective as possible.
But equally, we need to protect the dwindling populations of sharks that have lived in our planet's seas for millions of years. There is no justification for increasing a fishing quota that could see these ancient creatures disappear from our oceans.
Dr Gilly Llewellyn is World Wildlife Fund-Australia's oceans program leader
- Sent using Google Toolbar"