RONAN PRINCE-RUIZ is in year 12 at Perth Waldorf School, where for their final year students must do a year-long research project into a topic of their choosing. Ronan decided to look into increasing shark attacks in Western Australian waters and what measures can be used to prevent them. His findings might be quite a surprise to some.
WHILE shark attacks in Western Australia are still very rare, there are worrying signs they are increasing in frequency.
In the 70 years between 1925 and 1994 there were three fatalities linked to great white sharks.
Since then, there have been 22 fatal attacks or 20 times more attacks per year.
Unfortunately, the discussion on how to prevent more tragedies in the future has become very controversial, as people are forced to choose between killing all sharks and doing nothing. It doesn’t have to be this way.
Currently the main part of thegovernment’s Shark MitigationStrategy, as outlined by fisheriesminister Don Punch, relies on satellite tags on great white sharks, which will set off an alert when the shark is within a certain distance of a receiver buoy.
While this program provides much needed research on great whites, it does little to actually prevent attacks from happening.
The other part of the strategy is a $200 rebate for personal electronic deterrents.
While better than nothing, effective devices cannot be worn in many situations as they only attach to surf boards or boats and deter less than 50 per cent ofattacks at best. In January 2014, theWA government started a three-month trial of “smart” drumlines in response to a series of attacks off Perth beaches.
While the drumlines caught 172 sharks and destroyed 50 large tiger sharks, not a single great white – the type responsible for the attacks –was caught.
After receiving massivebacklash for the killing of so many fairly harmless sharks, the program was scrapped. Since then, any mention of policies that kill sharks has been pretty much avoided.
Stopping this program was certainly the right decision, as killing large numbers of a species rarely involved in attacks was never going to work.
Unfortunately, what most people took away from this incident was that drumlines, and control of shark populations in general, are environmentally damaging and completely ineffective.
The drumline trial didn’t fail because the method was flawed, it failed because it happened during late summer/early autumn. According to a study published by the Department of Fisheries and the CSIRO, this is the time when great white sharks are least common in WA.
The anti-drumline movement also ended the only actually effective shark control method.
In 2014, smart drumlines were set at the scene of attacks for a few days.
Any sharks not thought responsible for the attack were quickly released.
These lines caught three great whites, one of them only hours after an attack. While this was very controversial and the program was later binned, attacks have subsequently dropped by 70 per cent.
This system works because shark attacks aren’t random.
Great whites regularly hunt the same areas at the same time of year, and large sharks will develop their own unique hunting techniques.
It is when these techniques include humans as food that attacks happen.
A prime example of this is three very deliberate attacks by a five-metre plus great white within five kilometres on Perth beaches. All three attacks happened in similar conditions on almost the exact same date, almost certainly by the same shark.
While killing sharks is never ideal, a reintroduction of targeted drumlines would ensure only sharks involved in attacks are caught, without massive amounts of bycatch.
While the exact number is impossible to know for sure, the patterns in attacks suggest that most attacks in the past 20 years are probably the work of two or three sharks, and at least one of these sharks was caught in 2014.
Ultimately, any methods to reduce shark attacks needs to be effective while also having a minimal effect on the environment.
Killing sharks randomly, as done in the eastern states and trialled here in WA, can cause massive damage.
That doesn’t mean we should write the issue off as too hard.
A precise targeting of sharks that have been responsible for attacks would prevent needless deaths at a negligible cost to the oceans.