Loading ...In the 2009 southwards migration season, two humpback whales have been caught in Gold Coast shark nets in just a couple of weeks. As in most previous such events, the whales were released little worse for their experience, although smaller animals including calves have sometimes fared rather badly.
After the second whale was released, the observation was made that the frequency of whale enmeshment was increasing and more such events will occur in future, as whale numbers continue to increase with recovery of populations post-whaling.
Is this something we should be concerned about? The shark nets are there for a purpose, and if a few whales get caught, and later released relatively unharmed, is this any problem?
Well, that depends on how you weight up the costs and benefits of the shark meshing program.
Shark nets are strung along many beaches in Queensland with the intent of reducing the populations of inshore sharks, on the theory that, with relatively little inshore food for sharks, if the populations are low, the remaining sharks will be well-fed and therefore less likely to attack swimmers. If the result of this action is that less people are attacked by sharks, then the effort might be a good idea.
Of course, no action on the scale of meshing beaches is without unplanned effects, and, in addition to catching a couple of hundred sharks each year, the Gold Coast shark meshing program also catches a few whales and dugong, a dozen or so dolphins and sea turtles, and a lot of other medium-sized sea creatures such as rays and larger fish. A small number of endangered sharks such as grey nurse are caught, and even an occasional great white. Most of these creatures are killed in the process. This is a real cost to our marine environment, and it ought to have real benefits to be justified.
So, what are the benefits? Until recently, the Queensland shark meshing program had the proud history that in more than 40 years of operation on a dozen or so beaches from Cairns to the border, there had never been a single shark attack fatality on a meshed beach. This sounds like exactly the outcome that the scheme was implemented to achieve. Don’t be misled, however. Shark attack is a very rare event, and there might well have been no fatalities on these beaches over this time if the beaches had not been meshed.
On average, through the 20th century, there was less than one shark attack anywhere in Queensland each year. Across all of Australia, there has been less than one fatality from shark attack each year. Dying from shark attack is news-worthy and horrific, but it is very rare. In fact, it is hard to think of a way of dying that is less likely. Reams of ridiculous ways of dying can (and have) been quoted that are more likely than shark attack – let me quote just one: more Australians die from over-indulgence on Christmas day (alone) each year than from shark attack (after all, it only takes just one to be a higher risk).
Well does shark meshing reduce this infinitesimal risk? In fact it is not even proven that this program does reduce the risk because the theory behind the ‘population reduction’ program does not have solid foundations. For example, if there is so little food for the inshore sharks, it is not clear why they would not move elsewhere to feed rather than snacking on swimmers, and no-one has ever shown that sharks attacking people are hungry at the time they attack. Without these key facts, it is possible that the program achieves only a reduction in sightings of sharks, and not in encounters with people.
Proponents of the meshing program argue that confidence in the safety of our beaches is enhanced by the meshing program, and this may be true. I have conducted hundreds of surveys of beachgoers seeking their views on the meshing program and its importance to their decision to use the beach. The typical result is that 70 to 80 per cent did not know that their beach was ‘protected’ in this way, around 20 per cent did know but the fact was unimportant to them, and only two to five per cent reported that their choice to use the beach was conditional on the existence of the shark risk reduction program.
Typically these people were reluctant to enter the water nonetheless, citing other biting sea creatures, rips and currents or contamination of the water as reasons why they would not swim. In making a decision to enter the water, the presence of shark nets is important to no more than two per cent of beachgoers.
So, we do real environmental damage to reduce an infinitesimal risk to possibly no lower value, to satisfy less than one person in 50 on the beach.
There have to be better solutions.
Associate Professor Clyde Wild is the Dean (Academic) of Griffith’s Science, Environment, Engineering & Technology group.
